Watch the Moon Make a Pass at Earth’s Shadow, Then Kiss Regulus This Valentine’s Weekend

Regulus Occultion
The Moon occults Regulus of January 15th, 2017. Image credit and copyright: Lucca Ruggiero
Regulus Occultion
The Moon occults Regulus of January 15th, 2017. Image credit and copyright: Lucca Ruggiero

In the southern hemisphere this weekend in the ‘Land of Oz?’ Are you missing out on the passage of Comet 45/P Honda-Mrkos-Pajdušáková, and the penumbral lunar eclipse? Fear not, there’s an astronomical event designed just for you, as the Moon occults (passes in front of) the bright star Regulus on the evening of Saturday, January 11th.

The entire event is custom made for the continent of Australia and New Zealand, occurring under dark skies. Now for the bad news: the waning gibbous Moon will be less than 14 hours past Full during the event, meaning that the ingress (disappearance) of Regulus will occur along its bright leading limb and egress (reappearance) will occur on the dark limb. We prefer occultations during waxing phase, as the star winks out on the dark limb and seems to slowly fade back in on the bright limb.

The footprint for the February 11th occultation of Regulus by the Moon. Image credit: Occult 4.2 software

The International Occultation Timing Association has a complete list of precise ingress/egress times for cities located across the continent. An especially interesting region to catch the event lies along the northern graze line across the sparsely populated Cape York peninsula, just north of Cairns.

The northern grazeline for the February 11th occultation of Regulus by the Moon. Graphic by author.

The Moon occults Aldebaran and then Regulus six days later during every lunation in 2017. This is occultation number three in a cycle of 19 running from December 18, 2016 to April 24, 2018. The Moon occults Regulus 214 times in the 21st century, and Regulus is currently the closest bright star to the ecliptic plane, just 27′ away.

We’ve also got a very special event just under 14 hours prior, as a penumbral lunar eclipse occurs, visible on all continents… except Australia. Mid-eclipse occurs at 00:45 Universal Time (UT, Saturday morning on February 11th), or 7:45 PM Eastern Standard Time (EST) on the evening of Friday, February 10th, when observers may note a dusky shading on the northern limb of the Moon as the Moon just misses passing through the dark edge of the Earth’s inner umbral shadow. Regulus will sit less than seven degrees off of the lunar limb at mid-eclipse Friday night.

How often does an eclipsed Moon occult a bright star? Well, stick around until over four centuries from now on February 22nd, 2445, and observers based around the Indian Ocean region can watch just such an event, as the eclipsed Moon also occults Regulus. Let’s see, I should have my consciousness downloaded into my second android body by then…

A graphic study of the simultaneous lunar eclipse and occultation of Regulus in 2445. Credit: NASA/GSFC/Fred Espenak/Occult 4.2/Stellarium.

We’ll be streaming the Friday night eclipse live from Astroguyz HQ here in Spring Hill, Florida starting at 7:30 PM EST/00:30 UT, wifi-willing. Astronomer Gianluca Masi of the Virtual Telescope Project will also carry the eclipse live starting at 22:15 UT on the night of Friday, February 10th.

This eclipse also marks the start of eclipse season one of two, which climaxes with an annular eclipse crossing southern Africa and South America on February 26th. The second and final eclipse season of 2017 starts with a partial lunar eclipse on August 7th, which sets us up for the Great American Eclipse crossing the United States from coast to coast on August 21st, 2017.

A lunar occultation of Regulus also provides a shot at a unique scientific opportunity. Spectroscopic measurements suggest that the primary main sequence star possesses a small white dwarf companion, a partner which has never been directly observed. This unseen white dwarf may – depending on the unknown orientation of its orbit – make a brief appearance during ingress or egress for a fleeting split second, when the dark limb of the Moon has covered dazzling Regulus. High speed video might just nab a double step occlusion, as the white dwarf companion is probably about 10,000 times fainter than Regulus at magnitude +11 at the very brightest. Regulus is located 79 light years distant.

Our best results for capturing an occultation of a star or planet by the Moon have always been with a video camera aimed straight through our 8” Schmidt-Cassegrain telescope. The trick is always to keep the star visible in the frame near the brilliant Full Moon. Cropping the Moon out of the field as much as possible can help somewhat. Set up early, to work the bugs out of focusing, alignment, etc. We also run WWV radio in the background for an audible time hack on the video.

The January 15th, 2017 occultation of Regulus by the Moon. Image credit and copyright: Lucca Ruggiero.

The best occultation of Regulus by the Moon for North America in 2017 occurs on October 15th, when the Moon is at waning crescent phase. Unfortunately, the occultation of Regulus by asteroid 163 Erigone back in 2014 was clouded out, though the planet Venus occults the star on October 1st, 2044. Let’s see, by then I’ll be…

Comets and eclipses and occultations, oh my. It’s a busy weekend for observational astronomy, for sure. Consider it an early Valentine’s Day weekend gift from the Universe.

Webcasting the eclipse or the occultation this weekend? Let us know, and send those images of either event to Universe Today’s Flickr forum.

Read about eclipses, occultations and more tales of astronomy in our yearly guide 101 Astronomical Events For 2017, free from Universe Today.

101 Astronomical Events for 2017: A Teaser

A partial solar eclipse rising over the VAB. Image by author.

It’s that time of year again… time to look ahead at the top 101 astronomical events for the coming year.

And this year ’round, we finally took the plunge. After years of considering it, we took the next logical step in 2017 and expanded our yearly 101 Astronomical Events for the coming year into a full-fledged guide book, soon to be offered here for free download on Universe Today in the coming weeks. Hard to believe, we’ve been doing this look ahead in one form or another now since 2009.

This “blog post that takes six months to write” will be expanded into a full-fledged book. But the core idea is the same: the year in astronomy, distilled down into the very 101 best events worldwide. You will find the best occultations, bright comets, eclipses and much more. Each event will be interspersed with not only the ‘whens’ and ‘wheres,’ but fun facts, astronomical history, and heck, even a dash of astronomical poetry here and there.

It was our goal to take this beyond the realm of a simple almanac or Top 10 listicle, to something unique and special. Think of it as a cross between two classics we loved as a kid, Burnham’s Celestial Handbook and Guy Ottewell’s Astronomical Calendar, done up in as guide to the coming year in chronological format. Both references still reside on our desk, even in this age of digitization.

And we’ve incorporated reader feedback from over the years to make this forthcoming guide something special. Events will be laid out in chronological order, along with a quick-list for reference at the end. Each event is listed as a one- or two-page standalone entry, ready to be individually printed off as needed. We will also include 10 feature stories and true tales of astronomy. Some of these were  culled from the Universe Today archives, while others are new astronomical tales written just for the guide.

Great American Eclipse
Don’t miss 2017’s only total solar eclipse, crossing the United States! Image credit: Michael Zeiler/The Great American Eclipse.

The Best of the Best

Here’s a preview of some of the highlights for 2017:

-Solar cycle #24 begins to ebb in 2017. Are we heading towards yet another profound solar minimum?

-Brilliant Venus reaches greatest elongation in January and rules the dusk sky.

-45P/Honda-Mrkos-Pajdusakova passes 0.08 AU from Earth on February 11th, its closest passage for the remainder of the century.

-An annular solar eclipse spanning Africa and South America occurs on February 26th.

A sample occultation map from the book. Image credit: Occult 4.1.2.
A sample occultation map from the book. Image credit: Occult 4.1.2.

-A fine occultation of Aldebaran by the Moon on March 5th for North America… plus more occultations of the star worldwide during each lunation.

-A total solar eclipse spanning the contiguous United States on August 21st.

-A complex grouping of Mercury, Venus, Mars and the Moon in mid-September.

-Saturn’s rings at their widest for the decade.

Getting wider... the changing the of Saturn's rings. Image credit and copyright: Andrew Symes (@FailedProtostar).
Getting wider… the changing face of Saturn’s rings. Image credit and copyright: Andrew Symes (@FailedProtostar).

-A fine occultation of Regulus for North America on October 15th, with  occultations of the star by the Moon during every lunation for 2017.

-Asteroid 335 Roberta occults a +3rd magnitude star for northern Australia…

And that’s just for starters. Entries also cover greatest elongations for the inner planets and oppositions for the outer worlds, the very best asteroid occultations of bright stars, along with a brief look ahead at 2018.

Get ready for another great year of skywatching!

And as another teaser, here’s a link to a Google Calendar download of said events, complied by Chris Becke (@BeckePhysics). Thanks Chris!

Why Does Siberia Get All the Cool Meteors?

Credit: youtube frame grab


Children ice skating in Khakassia, Russia react to the fall of a bright fireball two nights ago on Dec.6

In 1908 it was Tunguska event, a meteorite exploded in mid-air, flattening 770 square miles of forest. 39 years later in 1947, 70 tons of iron meteorites pummeled the Sikhote-Alin Mountains, leaving more than 30 craters. Then a day before Valentine’s Day in 2013, hundreds of dashcams recorded the fiery and explosive entry of the Chelyabinsk meteoroid, which created a shock wave strong enough to blow out thousands of glass windows and litter the snowy fields and lakes with countless fusion-crusted space rocks.


Documentary footage from 1947 of the Sikhote-Alin fall and how a team of scientists trekked into the wilderness to find the craters and meteorite fragments

Now on Dec. 6, another fireball blazed across Siberian skies, briefly illuminated the land like a sunny day before breaking apart with a boom over the town of Sayanogorsk. Given its brilliance and the explosions heard, there’s a fair chance that meteorites may have landed on the ground. Hopefully, a team will attempt a search soon. As long as it doesn’t snow too soon after a fall, black stones and the holes they make in snow are relatively easy to spot.

This photo shows trees felled from a powerful aerial meteorite explosion. It was taken during Leonid Kulik's 1929 expedition to the Tunguska impact event in Siberia in 1908. Credit: Kulik Expedition
This photo shows trees felled from a powerful aerial meteorite explosion. It was taken during Leonid Kulik’s 1929 expedition to the Tunguska impact event in Siberia in 1908. Credit: Kulik Expedition

OK, maybe Siberia doesn’t get ALL the cool fireballs and meteorites, but it’s done well in the past century or so. Given the dimensions of the region — it covers 10% of the Earth’s surface and 57% of Russia — I suppose it’s inevitable that over so vast an area, regular fireball sightings and occasional monster meteorite falls would be the norm. For comparison, the United States covers only 1.9% of the Earth. So there’s at least a partial answer. Siberia’s just big.

A naturally sculpted iron-nickel meteorite recovered from the Sikhote-Alin meteorite fall in February 1947. The dimpling or "thumb-printing" occurs when softer minerals are melted and sloughed away as the meteorite is heated by the atmosphere while plunging to Earth. Credit: Svend Buhl
A naturally sculpted iron-nickel meteorite recovered from the Sikhote-Alin meteorite fall in February 1947. The dimpling or “thumb-printing” occurs when softer minerals are melted and sloughed away as the meteorite is heated by the atmosphere while plunging to Earth. Credit: Svend Buhl

Every day about 100 tons of meteoroids, which are fragments of dust and gravel from comets and asteroids, enter the Earth’s atmosphere. Much of it gets singed into fine dust, but the tougher stuff — mostly rocky, asteroid material — occasionally makes it to the ground as meteorites. Every day then our planet gains about a blue whale’s weight in cosmic debris. We’re practically swimming in the stuff!

Meteors are pieces of comet and asteroid debris that strike the atmosphere and burn up in a flash. Credit: Jimmy Westlake A brilliant Perseid meteor streaks along the Summer Milky Way as seen from Cinder Hills Overlook at Sunset Crater National Monument—12 August 2016 2:40 AM (0940 UT). It left a glowing ion trail that lasted about 30 seconds. The camera caught a twisting smoke trail that drifted southward over the course of several minutes.
Meteors are pieces of comet and asteroid debris that strike the atmosphere and burn up in a flash. Here, a brilliant Perseid meteor streaks along the Summer Milky Way this past August.  Credit: Jeremy Perez

Most of this mass is in the form of dust but a study done in 1996 and published in the Monthly Notices of the Royal Astronomical Society further broke down that number. In the 10 gram (weight of a paperclip or stick of gum) to 1 kilogram (2.2 lbs) size range, 6,400 to 16,000 lbs. (2900-7300 kilograms) of meteorites strike the Earth each year. Yet because the Earth is so vast and largely uninhabited, appearances to the contrary, only about 10 are witnessed falls later recovered by enterprising hunters.


A couple more videos of the Dec. 6, 2016 fireball over Khakassia and Sayanogorsk, Russia

Meteorites fall in a pattern from smallest first to biggest last to form what astronomers call a strewnfield, an elongated stretch of ground several miles long shaped something like an almond. If you can identify the meteor’s ground track, the land over which it streaked, that’s where to start your search for potential meteorites.

Meteorites indeed fall everywhere and have for as long as Earth’s been rolling around the sun. So why couldn’t just one fall in my neighborhood or on the way to work? Maybe if I moved to Siberia …

John Glenn: Godspeed and Rest in Peace

John Glenn during his Friendship 7 flight. Credit: NASA

John Glenn always had the right stuff.

Glenn, the first American astronaut to orbit the Earth and a legendary figure around the world, has died. Glenn, 95, was the last remaining Mercury astronaut, the first group of US astronauts. He flew on Friendship 7 on Feb. 20, 1962, and later flew on the space shuttle in 1998 at age 77, becoming the oldest astronaut to fly in space. He also spent 24 years as a U.S. Senator from Ohio, and had a run for the presidency.

Astronaut John Glenn views stencilling used as a model to paint the words "Friendship 7" on his spacecraft. Credit: NASA
Astronaut John Glenn views stencilling used as a model to paint the words “Friendship 7” on his spacecraft. Credit: NASA

Glenn will always be remembered as the first American to orbit the Earth during those tentative, challenging, daring days when humans were just beginning to venture beyond the atmosphere that had nurtured them since the species began. – NASA obituary of John Glenn

“With John’s passing, our nation has lost an icon and Michelle and I have lost a friend,” said President Obama said in a statement. Obama added that Glenn’s flight pioneering flight “reminded us that with courage and a spirit of discovery there’s no limit to the heights we can reach together.”

“On behalf of a grateful nation, Godspeed, John Glenn.”

“John spent his life breaking barriers, from defending our freedom as a decorated Marine Corps fighter pilot in World War II and Korea, to setting a transcontinental speed record, to becoming, at age 77, the oldest human to touch the stars,” Obama said. “John always had the right stuff, inspiring generations of scientists, engineers and astronauts who will take us to Mars and beyond — not just to visit, but to stay.”

Glenn, born on July 18, 1921, was described in statement by his family and Trevor Brown, dean of the John Glenn School of Public Affairs at Ohio State University, as “humble, funny, and generous.” And “even after leaving public life, he loved to meet with citizens, school children in particular. He thrilled to music and had a weakness for chocolate.”

Glen married his childhood sweetheart, Annie Castor, and studied at Muskingum College in Ohio. Glenn became a Marine Corps fighter and flew 59 combat missions during World War II and 90 in the Korean War.

Glenn attended Test Pilot School at the Naval Air Test Center, Patuxent River, Md. After graduation, he was project officer on a number of aircraft. In July 1957, he set a transcontinental speed record from Los Angeles to New York — 3 hours and 23 minutes. It was the first transcontinental flight to average supersonic speed.

Glenn accumulated nearly 9,000 hours of flying time, about 3,000 of it in jets.

The ‘space race’ began when the Soviet Union launched the first satellite, Sputnik, in 1957. After a series of failures for the US space program, they finally succeeded on February 1, 1958 when Explorer 1 became the first US satellite in space.

But the main goal was to send humans to space.

The original seven astronauts pose with an Atlas model July 12, 1962. The "en:Mercury Seven" astronauts pose with an Atlas model on July 12, 1962. Front row, left to right: Gus Grissom, Scott Carpenter, Deke Slayton and Gordon Cooper. Back row: Alan Shepard, Wally Schirra and John Glenn. Credit: NASA
The original seven astronauts pose with an Atlas model July 12, 1962. The ‘Mercury Seven’ astronauts pose with an Atlas model on July 12, 1962. Front row, left to right: Gus Grissom, Scott Carpenter, Deke Slayton and Gordon Cooper. Back row: Alan Shepard, Wally Schirra and John Glenn. Credit: NASA

In 1959, when the newly-formed National Aeronautics and Space Administration searched for the first Americans to fly in space, it focused on military test pilots. Glenn was in the select group – known as the Mercury 7 — who was chosen.

Glenn was assigned to the NASA Space Task Group at Langley, Va., in April 1959. The Space Task Group was moved to Houston and became part of the NASA Manned Spacecraft Center (which is now Johnson Space Center in Houston) in 1962.
While Glenn wasn’t chosen for the first Mercury space flight, his flight is well-remembered for being the first American to orbit Earth. But before any US astronauts could be launched into space, history was made on April 12, 1961 when Russian cosmonaut Yuri A. Gagarin became the first human in space when he completed his successful orbital flight aboard Vostok I.

Prior to Glenn’s 4-hour, 55-minute flight in Friendship 7, Glenn had served as backup pilot for astronauts Alan Shepard, the first American in space who flew on May 5, 1961, and to Virgil “Gus” Grissom, who followed Shepard on another suborbital flight on July 21, 1961.

On Feb. 20, 1962, Glenn launched from Cape Canaveral on Friendship 7, circling the earth three times. He became a national hero.

“Roger, liftoff, and the clock is running. We’re under way,” Glenn said after launch. After reaching space he said, “Zero-G and I feel fine. Man, that view is tremendous.”

Then-Senator Glenn joined the STS-95 Discovery crew in 1998, becoming the oldest person to fly in space at 77. Credit: NASA
Then-Senator Glenn joined the STS-95 Discovery crew in 1998, becoming the oldest person to fly in space at 77. Credit: NASA

Glenn was awarded the Presidential Medal of Freedom in 2012.

“The last of America’s first astronauts has left us, but propelled by their example we know that our future here on Earth compels us to keep reaching for the heavens,” Obama said.

Here are some tributes via Tweets for John Glenn:

Who was Giovanni Cassini?

Portrait of Giovanni Domenico Cassini, with the Paris Observatory in the background. Credit: Wikipedia Commons

During the Scientific Revolution, which took place between the 15th and 18th centuries, numerous inventions and discoveries were made that forever changed the way humanity viewed the Universe. And while this explosion in learning owed its existence to countless individuals, a few stand out as being especially worthy of praise and remembrance.

One such individual is Gionvanni Domenico Cassini, also known by his French name Jean-Dominique Cassini. An Italian astronomer, engineer, and astrologer, Cassini made many valuable contributions to modern science. However, it was his discovery of the gaps in Saturn’s rings and four of its largest moons for which he is most remembered, and the reason why the Cassini spacecraft bears his name.

Early Life and Education:

Giovanni Domenico Cassini was born on June 8th, 1625, in the small town of Perinaldo (near Nice, France) to Jacopo Cassini and Julia Crovesi. Educating by Jesuit scientists, he showed an aptitude for mathematics and astronomy from an early age. In 1648, he accepted a position at the observatory at Panzano, near Bologna, where he was employed by a rich amateur astronomer named Marquis Cornelio Malvasia.

During his time at the Panzano Observatory, Cassini was able to complete his education and went on to become the principal chair of astronomy at the University of Bologna by 1650. While there, he made several scientific contributions that would have a lasting mark.

La Meridiana, the meridian line calculated by Cassini while living in Bologna. Credit: Wikipedia Commons/Ilario/Cassinam
La Meridiana, the meridian line calculated by Cassini while living in Bologna. Credit: Wikipedia Commons/Ilario/Cassinam

This included the calculation of an important meridian line, which runs along the left aisle of the San Petronio Basilica in Bologna. At 66.8 meters (219 ft) in length, it is one of the largest astronomical instruments in the worl and allowed for measurements that were (at the time) uniquely precise. This meridian also helped to settle the debate about whether or not the Universe was geocentric or heliocentric.

During his time in Italy, Cassini determined the obliquity of the Earth’s ecliptic  – aka. it’s axial tilt, which he calculated to be 23° and 29′ at the time. He also studied the effects of refraction and the Solar parallax, worked on planetary theory, and observed the comets of 1664 and 1668.

In recognition of his engineering skills, Pope Clement IX employed Cassini with regard to fortifications, river management and flooding along the Po River in northern Italy. In 1663, Cassini was named superintendent of fortifications and oversaw the fortifying of Urbino. And in 1665, he was named the inspector for the town of Perugia in central Italy.

Paris Observatory:

In 1669, Cassini received an invitation by Louis XIV of France to move to Paris and help establish the Paris Observatory. Upon his arrival, he joined the newly-founded Academie Royale des Sciences (Royal Academy of Sciences), and became the first director of the Paris Observatory, which opened in 1671. He would remain the director of the observatory until his death in 1712.

An engraving of the Paris Observatory during Cassini's time. Credit: Public Domain
An engraving of the Paris Observatory during Cassini’s time. Credit: Public Domain

In 1673, Cassini obtained his French citizenship and in the following year, he married Geneviève de Laistre, the daughter of the lieutenant general of the Comte de Clermont. During his time in France, Cassini spent the majority of his time dedicated to astronomical studies. Using a series of very long air telescopes, he made several discoveries and collaborated with Christiaan Huygens in many projects.

In the 1670s, Cassini began using the triangulation method to create a topographic map of France. It would not be completed until after his death (1789 or 1793), when it was published under the name Carte de Cassini. In addition to being the first topographical map of France, it was the first map to accurately measure longitude and latitude, and showed that the nation was smaller than previously thought.

In 1672, Cassini and his colleague Jean Richer made simultaneous observations of Mars (Cassini from Paris and Richer from French Guiana) and determined its distance to Earth through parallax. This enabled him to refine the dimensions of the Solar System and determine the value of the Astronomical Unit (AU) to within 7% accuracy. He and English astronomer Robert Hooke share credit for the discovery of the Great Red Spot on Jupiter (ca. 1665).

In 1683, Cassini presented an explanation for “zodiacal light” – the faint glow that extends away from the Sun in the ecliptic plane of the sky – which he correctly assumed to be caused by a cloud of small particles surrounding the Sun. He also viewed eight more comets before his death, which appeared in the night sky in 1672, 1677, 1698, 1699, 1702 (two), 1706 and 1707.

Illustration of Jupiter and the Galilean satellites. Credit: NASA
Illustration of Jupiter and the Galilean satellites. Credit: NASA

In ca. 1690, Cassini was the first to observe differential rotation within Jupiter’s atmosphere. He created improved tables for the positions of Jupiter’s Galilean moons, and discovered the periodic delays between the occultations of Jupiter’s moons and the times calculated. This would be used by Ole Roemer, his colleague at the Paris Observatory, to calculate the velocity of light in 1675.

In 1683, Cassini began the measurement of the arc of the meridian (longitude line) through Paris. From the results, he concluded that Earth is somewhat elongated. While in fact, the Earth is flattened at the poles, the revelation that Earth is not a perfect sphere was groundbreaking.

Cassini also observed and published his observations about the surface markings on Mars, which had been previously observed by Huygens but not published. He also determined the rotation periods of Mars and Jupiter, and his observations of the Moon led to the Cassini Laws, which provide a compact description of the motion of the Moon. These laws state that:

  1. The Moon takes the same amount of time to rotate uniformly about its own axis asit takes to revolve around the Earth. As a consequence, the same face is always pointed towards Earth.
  2. The Moon’s equator is tilted at a constant angle (about 1°32′ of arc) to the plane of the Earth’s orbit around the Sun (i.e. the ecliptic)
  3. The point where the lunar orbit passes from south to north on the ecliptic (aka. the ascending node of the lunar orbit) always coincides with the point where the lunar equator passes from north to south on the ecliptic (the descending node of the lunar equator).
A collage of Saturn (bottom left) and some of its moons: Titan, Enceladus, Dione, Rhea and Helene. Credit: NASA/JPL/Space Science Institute
A collage of Saturn (bottom left) and some of its moons: Titan, Enceladus, Dione, Rhea and Helene. Credit: NASA/JPL/Space Science Institute

Thanks to his leadership, Giovanni Cassini was the first of four successive Paris Observatory directors that bore his name. This would include his son, Jaques Cassini (Cassini II, 1677-1756); his grandson César François Cassini (Cassini III, 1714-84); and his great grandson, Jean Dominique Cassini (Cassini IV, 1748-1845).

Observations of Saturn:

During his time in France, Cassini also made his famous discoveries of many of Saturn’s moons – Iapetus in 1671, Rhea in 167, and Tethys and Dione in 1684. Cassini named these moons Sidera Lodoicea (the stars of Louis), and correctly explained the anomalous variations in brightness to the presence of dark material on one hemisphere (now called Cassini Regio in his honor).

In 1675, Cassini discovered that Saturn’s rings are separated into two parts by a gap, which is now called the “Cassini Division” in his honor. He also theorized that the rings were composed of countless small particles, which was proven to be correct.

Death and Legacy:

After dedicating his life to astronomy and the Paris Observatory, Cassini went blind in 1711 and then died on September 14th, 1712, in Paris. And although he resisted many new theories and ideas that were proposed during his lifetime, his discoveries and contributions place him among the most important astronomers of the 17th and 18th centuries.

A comparison of the geocentric and heliocentric models of the universe. Credit: history.ucsb.edu
A comparison of the geocentric and heliocentric models of the universe. Credit: history.ucsb.edu

As a traditionalist, Cassini initially held the Earth to be the center of the Solar System. In time, he would come to accept the Solar Theory of Nicolaus Copernicus within limits, to the point that he accepted the model proposed by Tycho Brahe. However, he rejected the theory of Johannes Kepler that planets travel in ellipses and proposed hat their paths were certain curved ovals (i.e. Cassinians, or Ovals of Cassini)

Cassini also rejected Newton’s Theory of Gravity, after measurements he conducted which (wrongly) suggested that the Earth was elongated at its poles. After forty years of controversy, Newton’s theory was adopted after the measurements of the French Geodesic Mission (1736-1744) and the Lapponian Expedition in 1737, which showed that the Earth is actually flattened at the poles.

For his lifetime of work, Cassini has been honored in many ways by the astronomical community. Because of his observations of the Moon and Mars, features on their respective surfaces were named after him. Both the Moon and Mars have their own Cassini Crater, and Cassini Regio on Saturn’s moon Iapetus also bears his name.

Then there is Asteroid (24101) Cassini, which was discovered by C.W. Juels at in 1999 using the Fountain Hills Observatory telescope. Most recently, there was the joint NASA-ESA Cassini-Huygens missions which recently finished its mission to study Saturn and its moons. This robotic orbiter and lander mission was named in honor of the two astronomers who were chiefly responsible for discovering Saturn system of moons.

 Artist's impression of the Cassini space probe, part of the Cassini-Huygens mission to explore Saturn and its moons. Credit: NASA/JPL
Artist’s impression of the Cassini space probe, part of the Cassini-Huygens mission to explore Saturn and its moons. Credit: NASA/JPL

In the end, Cassini’s passion for astronomy and his contributions to the sciences have ensured him a lasting place in the annals of history. In any discussion of the Scientific Revolution and of the influential thinkers who made it happen, his name appears alongside such luminaries as Copernicus, Galileo, and Newton.

We have written many interesting articles about Giovanni Cassini here at Universe Today. Here’s How Many Moons Does Saturn Have?, The Planet Saturn, Saturn’s Moon Rhea, Saturn’s “Yin-Yang” Moon Iapetus, Saturn’s Moon Dione.

For more information, be sure to check out NASA’s Cassini-Huygens mission page, and the ESA’s as well.

Astronomy Cast also has some interesting episodes on the subject. Here’s Episode 229: Cassini Mission, and Episode 230: Christiaan Huygens.

Sources:

Who Was The First Woman To Go Into Space?

Soviet Cosmonaut Valentina Tereshkova photographed inside the Vostok-6 spacecraft on June 16, 1963. Credit: Roscosmos

When it comes to the “Space Race” of the 1960s, several names come to mind. Names like Chuck Yeager, Yuri Gagarin, Alan Shepard, and Neil Armstrong, but to name a few. These men were all pioneers, braving incredible odds and hazards in order to put a man into orbit, on the Moon, and bring humanity into the Space Age. But about the first women in space?

Were the challenges they faced any less real? Or were they even more difficult considering the fact that space travel – like many professions at the time – was still thought to be a “man’s game”? Well, the first woman to break this glass ceiling was Valentina Tereshkova, a Soviet Cosmonaut who has the distinction of being the first woman ever to go into space as part of the Vostok 6 mission.

Early Life:

Tereshkova was born in the village of Maslennikovo in central Russia (about 280 km north-east of Moscow) after her parents migrated from Belarus. Her father was a tractor driver and her mother worked in a textile plant. Her father became a tank officer and died during the Winter War (1939-1940) when the Soviet Union invaded Finland over a territorial dispute.

Russian BT-5 tank destroyed during the Winter War (1939-1940). Credit: SA-kuva/Finnish army pictures
Russian BT-5 tank destroyed during the Winter War (1939-1940). Credit: Wikipedia Commons/SA-kuva/Finnish Army Pictures

Between 1945 to 1953, Tereshkova went to school but dropped out when she was sixteen, and completed her education through correspondence. Following in her mother’s footsteps, she began working at a textile factory, where she remained until becoming part of the Soviet cosmonaut program.

She became interested in parachuting from a young age and trained in skydiving at the local Aeroclub. In 1959, at the age of 22, she made her first jump. It was her expertise in skydiving that led to her being selected as a cosmonaut candidate a few years later. In 1961, she became the secretary of the local Komsomol (Young Communist League) and later joined the Communist Party of the Soviet Union.

Vostok Program:

Much like Yuri Gagarin, Tereshkova took part in the Vostok program, which was the Soviet Unions’ first attempt at putting crewed missions into space. After the historic flight of Gagarin in 1961, Sergey Korolyov – the chief Soviet rocket engineer – proposed sending a female cosmonaut into space as well.

At the time, the Soviets believed that sending women into space would achieve a propaganda victory against the U.S., which maintained a policy of only using military and test pilots as astronauts. Though this policy did not specifically discriminate on the basis of gender, the lack of women combat and test pilots effectively excluded them from participating.

Valentina Tereshkova, pilot-cosmonaut, first female cosmonaut, Hero of the USSR. Pictured as a Major of the Soviet Air Forces. Credit: RIA Novosti/Alexander Mokletsov
Valentina Tereshkova, pilot-cosmonaut, first female cosmonaut, Hero of the USSR. Pictured as a Major of the Soviet Air Forces. Credit: RIA Novosti/Alexander Mokletsov

In April 1962, five women were chosen for the program out of hundreds of potential candidates. These included Tatyana Kuznetsova, Irina Solovyova, Zhanna Yorkina, Valentina Ponomaryova, and Valentina Tereshkova. In order to qualify, the women needed to be parachutists under 30 years of age, under 170 cm (5’7″) in height, and under 70 kg (154 lbs.) in weight.

Along with four colleagues, Tereshkova spent several months in training. This included weightless flights, isolation tests, centrifuge tests, rocket theory, spacecraft engineering,  parachute jumps, and pilot training in jet aircraft. Their examinations concluded in November 1962, after which Tereshkova and Ponomaryova were considered the leading candidates.

A joint mission profile was developed that would see two women launched into space on separate Vostok missions in March or April of 1963. Tereshkova, then 25, was chosen to be the first woman to go into space, for multiple reasons. First, there was the fact that she conformed to the height and weight specifications to fit inside the relatively cramped Vostok module.

Second, she was a qualified parachutist, which given the nature of the Vostok space craft (the re-entry craft was incapable of landing) was absolutely essential. The third, and perhaps most important reason, was her strong “proletariat” and patriotic background, which was evident from her family’s work and the death of her father (Vladimir Tereshkova) during the Second World War.

The Vostok 6 capsule at the Science Museum, London. Credit: Wikipedia Commons/Andrew Grey
The Vostok 6 capsule at the Science Museum, London. Credit: Wikipedia Commons/Andrew Grey

Originally, the plan was for Tereshkova to launch first in the Vostok 5 ship while Ponomaryova would follow her into orbit in Vostok 6. However, this flight plan was altered in March 1963, with a male cosmonaut flying Vostok 5 while Tereshkova would fly aboard Vostok 6 in June 1963. After watching the successful launch of Vostok 5 on 14 June, Tereshkova (now 26) began final preparations for her own flight.

Launch:

Tereshkova’s Vostok 6 flight took place on the morning of June 16th, 1963. After performing communications and life support checks, she was sealed inside the capsule and the mission’s two-hour countdown began. The launch took place at 09:29:52 UTC with the rocket lifting off faultlessly from the Baikonur launchpad.

During the flight – which lasted for two days and 22 hours – Tereshkova orbited the Earth forty-eight times. Her flight took place only two days after Vostok 5 was launched, piloted by Valery Bykovsky, and orbited the Earth simultaneously with his craft. In the course of her flight, ground crews collected data on her body’s reaction to spaceflight.

Aside from some nausea (which she later claimed was due to poor food!) she maintained herself for the full three days. Like other cosmonauts on Vostok missions, she kept a flight log and took photographs of the horizon – which were later used to identify aerosol layers within the atmosphere – and manually oriented the spacecraft.

First woman in space Soviet cosmonaut Valentina Tereshkova is seen during a training session aboard a Vostok spacecraft simulator on January 17, 1964. Credit: AFP Photo / RIA Novosti
First woman in space Soviet cosmonaut Valentina Tereshkova is seen during a training session aboard a Vostok spacecraft simulator on January 17, 1964. Credit: AFP Photo / RIA Novosti

On the first day of her mission, she reported an error in the control program, which made the spaceship ascend from orbit instead of descending. The team on Earth provided Tereshkova with new data to enter into the descent program which corrected the problem. After completing 48 orbits, her craft began descending towards Earth.

Once the craft re-entered the atmosphere, Tereshkova ejected from the capsule and parachuted back to earth. She landed hard after a high wind blew her off course, which was fortunate since she was descending towards a lake at the time. However, the landing caused her to seriously bruise her face, and heavy makeup was needed for the public appearances that followed.

Vostok 6 would be the last of the Vostok missions, despite there being plans for further flights involving women cosmonauts. None of the other four in Tereshkova’s early group got a chance to fly, and, in October of 1969, the pioneering female cosmonaut group was dissolved. It would be 19 years before another woman would fly as part of the Soviet space program –  Svetlana Savitskaya, who flew as part of the Soyuz T-7 mission.

After Vostok 6:

After returning home, certain elements within the Soviet Air Force attempted to discredit Tereshkova. There were those who said that she was drunk when she reported to the launch pad and was insubordinate while in orbit. These charges appeared to be related to the sickness she experienced while in space, and the fact that she issued corrections to the ground control team – which was apparently seen as a slight.

Nikita Khrushchev, Valentina Tereshkova, Pavel Popovich and Yury Gagarin at Lenin Mausoleum on June 22nd, 1963. Credit: Wikipedia Commons/RIA Novosti Archive
Nikita Khrushchev, Valentina Tereshkova, Pavel Popovich and Yury Gagarin at Lenin Mausoleum on June 22nd, 1963. Credit: Wikipedia Commons/RIA Novosti Archive

She was also accused of drunken and disorderly conduct when confronting a militia Captain in Gorkiy. However, General Nikolai Kamanin – the head of cosmonaut training in the Soviet space program at the time – defended Tereshkova’s character and dismissed her detractors instead. Tereshkova’s reputation remained unblemished and she went on to become a cosmonaut engineer and spent the rest of her life in key political positions.

In November of 1963, Tereshkova married Andrian Nikolayev, another Soviet cosmonaut, at a wedding that took place at the Moscow Wedding Palace. Khrushchev himself presided, with top government and space program leaders in attendance. In June of 1964, she gave birth to their daughter Elena Andrianovna Nikolaeva-Tereshkova, who became the first person in history to have both a mother and father who had traveled into space.

She and Nikolayev divorced in 1982, and Nikolayev died in 2004. She went on to remarry an orthopaedist named Yuliy G. Sharposhnikov, who died in 1999. After her historic flight, Tereshkova enrolled at the Zhukovsky Air Force Academy and graduated with distinction as a cosmonaut engineer. In 1977, she earned her doctorate in engineering.

Her fame as a cosmonaut also led to several key political positions. Between 1966 and 1974, she was a member of the Supreme Soviet of the Soviet Union. She was also a member of the Presidium of the Supreme Soviet from 1974 to 1989, and a Central Committee Member from 1969 to 1991. Her accomplishments also led to her becoming a representative of the Soviet Union abroad.

The wedding ceremony of pilot-cosmonauts Valentina Tereshkova and Andriyan Nikolayev, Nov. 3rd, 1963. Credit: RIA Novosti Archive/ Alexander Mokletsov
The wedding ceremony of pilot-cosmonauts Valentina Tereshkova and Andriyan Nikolayev, Nov. 3rd, 1963. Credit: RIA Novosti Archive/Alexander Mokletsov

In addition to becoming a member of the World Peace Council in 1966, the vice president of the International Women’s Democratic Federation and president of the Soviet-Algerian Friendship Society. She also represented the Soviet Union at the UN Conference for the International Women’s Year in Mexico City in 1975 and led the Soviet delegation to the World Conference on Women in Copenhagen.

After the collapse of the Soviet Union, Tereshkova lost her political office but remained an important public figure. To this day, she is revered as a hero and a major contributor to the Russian space program. In 2011, she was elected to the State Duma (the lower house of the Russian legislature) where she continues to serve.

In 2008, Tereshkova was invited to Prime Minister Vladimir Putin’s residence in Novo-Ogaryovo for the celebration of her 70th birthday. In that same year, she became a torchbearer of the 2008 Summer Olympics torch relay in Saint Petersburg, Russia. She has also expressed interest in traveling to Mars, even if it were a one-way trip.

Legacy and Honors:

For her accomplishments, Tereshkova has received many honors and awards. She has been decorated with the Hero of the Soviet Union medal (the USSR’s highest award) as well as the Order of Lenin, the Order of the October Revolution, and many other medals.

Foreign governments have also awarded her with the Karl Marx Order, the Hero of Socialist Labor of Czechoslovakia, the Hero of Labor of Vietnam, the Hero of Mongolia, the UN Gold Medal of Peace, and the Simba International Women’s Movement Award. She has honorary citizenship in multiple cities from Bulgaria, Slovakia, Belarus and Mongolia in the east, to Switzerland, France, and the UK in the west.

Russian astronauts Andrian G. Nikolayev and Valentina Tereshkova. Creditl Wikipeida Commons/
Commemorative Hungarian stamp featuring Soviet cosmonauts Valentina Tereshkova and Andrian G. Nikolayev (her husband). Credit: Wikipedia Commons/Darjac

Due to her pioneering role in space exploration, a number of astronomical objects and features are named in her honor. For example, the Tereshkova crater on the far side of the Moon was named after her. The minor planet 1671 Chaika (which translates to “Seagull” in Russian) is named in honor of her Vostok 6 mission call sign.

Numerous monuments and statues have been erected in her honor and the Monument to the Conquerors of Space in Moscow features her image. Streets all across the former Soviet Union and Eastern Bloc nations were renamed in her honor, as was the school in Yaroslavl where she studied as a child. The Yaroslavl Planetarium, built in 2011, was created in her honor, and the Museum of V.V. Tereshkova – Cosmos exists near her native village of Maslennikovo.

The Space Age was a time of truly amazing accomplishments. Not only did astronauts like Tereshkova break the surly bonds of Earth, but they also demonstrated that space exploration knows no gender restrictions. And though it would be decades before people like Svetlana Savitskaya and Sally Ride would into space, Tereshkova will forever be remembered as the woman who blazed the trail for all female astronauts.

We have written many articles about Valentina Tereshkova for Universe Today. Here’s Who are the Most Famous Astronauts?, From Space to the Olympics, What is the Space Age?, Who was the First Man to go into Space?, Who was the First Dog to go into Space?, Who was the First Monkey to go into Space?, and How Many Dogs Have been into Space?

If you’d like more info on Valentina Tereshkova, check out NASA StarChild: Valentina Tereshkova, and here’s a link to NASA Imagine the Universe: First Women in Space.

Astronomy Cast also has some good episodes on the subject. Here’s Episode 124: Space Capsules. Part I – Vostok, Mercury and Gemini.

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What was Sputnik One?

Sputnik 1
Photograph of a Russian technician putting the finishing touches on Sputnik 1, humanity's first artificial satellite. Credit: NASA/Asif A. Siddiqi

Today, people take it for granted that they live in a world that isn’t threatened with imminent nuclear annihilation. A little more than half a century ago, that was the kind of world people lived in, where the United States and Soviet Union were locked in a constant game of one-upmanship that revolved around the development of nuclear weapons.

At the same time, this competition extended to include sports, politics, and the race to reach space. And on October 4th, 1957, the Russians were the first to accomplish this goal with the launch of Sputnik-1, an unmanned research and communications satellite whose appearance ignited the “Space Race” and forever altered the course of history.

Background:

During the early 1950s, the Russians had conducted extensive orbital research using rockets. However, these efforts were limited by the fact that conventional rockets could only achieve orbit for a maximum of a few minutes before falling back to Earth. The next step seemed obvious: placing a research satellite into space that could maintain its orbit and therefore conduct scientific research for an extended period of time.

A "Semyorka" rocket, part of the Soviet R7 rocket family. Credit: Wikipedia Commons/Sergei Arssenev
Sputnik 1 was launched aboard a “Semyorka” rocket, part of the Soviet R7 rocket family. Credit: Wikipedia Commons/Sergei Arssenev

Beginning in March of 1954, Russia’s three top scientists – Mstislav Keldysh, Sergei Korolev and Mikhail Tikhonravov – began discussing the idea of creating an artificial satellite that could be placed into orbit. According to Tikhonravov, such a move would be the next necessary step in the development of rocket technology.

Their efforts received a boost when, on July 29th, 1955, U.S. President Dwight D. Eisinhower announced the US’ intent to launch an artificial satellite during the International Geophysical Year (IGY) – an international scientific project that lasted from July 1st, 1957, to December 31st, 1958.

Because of this, the Soviet Politburo approved of the plans for an artificial satellites and aimed for a launch date that would take place before the beginning of the IGY. The project was approve and the task of creating it was divided between various ministries and the USSR Academy of Sciences.

Keldysh was given control of a commission to oversee develop the “automatic laboratory” aboard the satellite, Tikhonravov and his team of engineers would be responsible for designing the satellite, and Korolev – as head of the Ministry of Defense Industry’s primary design bureau (OKB-1) – would be responsible for building it.

The Sputnik spacecraft stunned the world when it was launched into orbit on Oct. 4th, 1954. Credit: NASA
The Sputnik spacecraft stunned the world when it was launched into orbit on Oct. 4th, 1954. Credit: NASA

Design and Construction:

Initially, the Soviet plan for an satellite (known as Object D) was planned to be completed in 1957–58, and called for the creation of a spacecraft that would have a mass of 1,000 – 1,400 kg (2,200 – 3,100 lb) and would carry 200 – 300 kg (440 – 660 lb) of scientific instruments.

In terms of tasks, the mission would seek to measure the density of the atmosphere and its ion composition, solar wind, the Earth’s magnetic field, and cosmic rays (largely for the sake of future missions). A system of ground stations was also called for in order to collect data transmitted from the satellite, as well as observe its orbit and transmit commands.

By the end of 1956, it had become clear that the specifications called for were too ambitious to be accomplished within the established time frame. Fearing the US would launch a satellite before the USSR, Korolev and the OKB-1 suggested that a simpler, lighter satellite could be launched in April-May 1957, before the IGY began.

This satellite would weight about 100 kg (220 lbs) and would forgo heavy scientific instruments in favor of a simple radio transmitter. On February 15th, 1957, the Council of Ministers of the USSR approved this simple satellite, designated “Prosteyshiy Sputnik” – Russian for “Simplest Satellite” – (aka. Object PS), and made arrangements to launch two versions (PS-1 and PS-2) using R-7 rockets.

Exploded view of the Sputnik 1 satellite. Credit: NASA
Exploded view of the Sputnik 1 satellite. Credit: NASA

 

Launch and Mission:

On October 4th, at 19:28:34 hours Greenwich Mean Time, Sputnik-1 was launched into space from the Baikonur Cosmodrome. The satellite orbited the Earth for three months and emitting radio signals which were monitored by amateur radio operators throughout the world. The signals continued for 22 days until the transmitter batteries ran out on October 26th, 1957.

Before finally burning up during reentry on January 4th, 1958, the satellite traveled a total of about 60 million km (37.28 million mi) and completed 1,440 orbits around the Earth. Sputnik-1 also helped to identify the density of the atmosphere’s upper layer, provided data on radio-signal distribution in the ionosphere, and allowed for the first opportunity for meteoroid detection.

Impact:

Apart from its value as a technological first, Sputnik also had the effect of expediting both Soviet and American efforts to explore space. News of the launch triggered a great deal of fear in the United States, as many worried that Sputnik could represent a threat to national security, not to mention America’s technological leadership.

As a result, Congress urged then-President Dwight D. Eisenhower to take immediate action, which resulted in the signing of the National Aeronautics and Space Act on July 29th, 1958, officially establishing NASA. Immediately, NASA became dedicated to researching hypersonic flight and taking the necessary steps towards creating crewed spacecraft.

Yury Gagarin before a space flight aboard the Vostok spacecraft. April 12, 1961 Credit: RIA Novosti
Yury Gagarin before a space flight aboard the Vostok spacecraft. April 12, 1961 Credit: RIA Novosti

The Soviets did the same, taking drastic steps towards the creation of rockets and crew capsules as part of the Vostok Program. This would culminate in the first man being launched into orbit space – cosmonaut Yuri Gagarin – on April 12th, 1961. The pace of this competition would continue until July 20th, 1969, when the US made the historic first of landing astronauts on the Moon.

Decades later, Sputnik-1 is still viewed as a groundbreaking achievement. Despite its diminutive size and simplicity, its launch was a major breakthrough for the Soviets, and caused no shortage of fear and consternation in the west. In many ways, we are lucky to be living in an age where cooperation has taken the place of competition. Today, such breakthroughs are the result of a world coming together, and not enmity between nations.

We have written many articles about the satellites and Space Age here at Universe Today. Here’s Who was the First Dog to go into Space?, Who was the First Monkey to go into Space?, Who was the first Man to go into Space?, Who was the First Woman to go into Space? and Who Are The Most Famous Astronauts?

If you’d like more information on the Sputnik mission, here’s a link to NASA’s Solar System Exploration Guide on Sputnik, and here’s the homepage for NASA History: Sputnik.

We’ve recorded an episode of Astronomy Cast all about the History of Astronomy. Listen here, Episode 187: History of Astronomy, Part 5: The 20th Century.

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What Were the First Lunar Landings?

A picture of Earth taken by Apollo 11 astronauts. Credit: NASA

The moment that the Apollo-11 mission touched down on the Moon, followed by Neil Armstrong‘s famous words – “That’s one small step for [a] man, one giant leap for mankind” – is one of the most iconic moments in history. The culmination of years of hard work and sacrifice, it was an achievement that forever established humanity as a space-faring species.

And in the year’s that followed, several more spacecraft and astronauts landed on the Moon. But before, during and after these missions, a number of other “lunar landings” were accomplished as well. Aside from astronauts, a number of robotic missions were mounted which were milestones in themselves. So exactly what were the earliest lunar landings?

Robotic Missions:

The first missions to the Moon consisted of probes and landers, the purpose of which was to study the lunar surface and determine where crewed missions might land. This took place during the 1950s where both the Soviet Space program and NASA sent landers to the Moon as part of their Luna and Pioneer programs.

The Soviet Luna 2 probe, the first man-made object to land on the Moon. Credit: NASA
The Soviet Luna 2 probe, the first man-made object to land on the Moon. Credit: NASA

After several attempts on both sides, the Soviets managed to achieve a successful lunar landing on Sept. 14th, 1959 with their Luna-2 spacecraft. After flying directly to the Moon for 36 hours, the spacecraft achieved a hard landing (i.e. crashed) on the surface west of the Mare Serenitatis – near the craters Aristides, Archimedes, and Autolycus.

The primary objective of the probe was to help confirm the discovery of the solar wind, turned up by the Luna-1 mission. However, with this crash landing, it became the first man-made object to touch down on the Moon. Upon impact, it scattered a series of Soviet emblems and ribbons that had been assembled into spheres, and which broke apart upon hitting the surface.

The next craft to make a lunar landing was the Soviet Luna-3 probe, almost a month after Luna-2 did. However, unlike its predecessor, the Luna-3 probe was equipped with a camera and managed to send back the first images of the far side of the Moon.

The first US spacecraft to impact the Moon was the Ranger-7 probe, which crashed into the Moon on July 31st, 1964. This came after a string of failures with previous spacecraft in the Pioneer and Ranger line of robotic spacecraft. Prior to impact, it too transmitted back photographs of the Lunar surface.

The Ranger 7 lander, which became the first US spacecraft to land on the Moon. Credit: NASA
The Ranger 7 lander, which became the first US spacecraft to land on the Moon. Credit: NASA

This was followed by the Ranger-8 lander, which impacted the surface of the Moon on Feb. 20th, 1965. The spacecraft took 7,000 high-resolution images of the Moon before crashing onto the surface, just 24 km from the Sea of Tranquility, which NASA had been surveying for the sake of their future Apollo missions. These images, which yielded details about the local terrain, helped to pave the way for crewed missions.

The first spacecraft to make a soft landing on the Moon was the Soviet Luna-9 mission, on February 3rd, 1966. This was accomplished through the use of an airbag system that allowed the probe to survive hitting the surface at a speed of 50 km/hour. It also became the first spacecraft to transmit photographic data back to Earth from the surface of another celestial body.

The first truly soft landing was made by the US with the Surveyor-1 spacecraft, which touched down on the surface of the Moon on June 2nd, 1966. After landing in the Ocean of Storms, the probe transmitted data back to Earth that would also prove useful for the eventual Apollo missions.

Several more Surveyor missions and one more Luna mission landed on the Moon before crewed mission began, as part of NASA’s Apollo program.

Launch of Apollo 11. On July 16, 1969, the huge, 363-feet tall Saturn V rocket launches on the Apollo 11 mission from Pad A, Launch Complex 39, Kennedy Space Center, at 9:32 a.m. EDT. Onboard the Apollo 11 spacecraft are astronauts Neil A. Armstrong, commander; Michael Collins, command module pilot; and Edwin E. Aldrin Jr., lunar module pilot. Apollo 11 was the United States' first lunar landing mission. While astronauts Armstrong and Aldrin descended in the Lunar Module "Eagle" to explore the Sea of Tranquility region of the moon, astronaut Collins remained with the Command and Service Modules "Columbia" in lunar orbit. Image credit: NASA
Launch of Apollo 11 mission aboard a Saturn V rocket on July 16th, 1969. Credit: NASA

Crewed Missions:

The first crewed landing on the Moon was none other than the historic Apollo-11 mission, which touched down on the lunar surface on July 20th, 1969. After achieving orbit around the Moon in their Command Module (aka. the Columbia module), Neil Armstrong and Buzz Aldrin rode the Lunar Excursion (Eagle) Module down to the surface of the Moon.

Once they had landed, Armstrong radioed to Mission Control and announced their arrival by saying: “Houston, Tranquility Base here. The Eagle has landed.” Once the crew had gone through their checklist and depressurized the cabin, the Eagles’ hatch was opened and Armstrong began walking down the ladder to the Lunar surface first.

When he reached the bottom of the ladder, Armstrong said: “I’m going to step off the LEM now” (referring to the Lunar Excursion Module). He then turned and set his left boot on the surface of the Moon at 2:56 UTC July 21st, 1969, and spoke the famous words “That’s one small step for [a] man, one giant leap for mankind.”

About 20 minutes after the first step, Aldrin joined Armstrong on the surface and became the second human to set foot on the Moon. The two then unveiled a plaque commemorating their flight, set up the Early Apollo Scientific Experiment Package, and planted the flag of the United States before blasting off in the Lunar Module.

Aldrin on the Moon. Astronaut Buzz Aldrin walks on the surface of the moon near the leg of the lunar module Eagle during the Apollo 11 mission. Mission commander Neil Armstrong took this photograph with a 70mm lunar surface camera. While astronauts Armstrong and Aldrin explored the Sea of Tranquility region of the moon, astronaut Michael Collins remained with the command and service modules in lunar orbit. Image Credit: NASA
Buzz Aldrin on the Moon during the Apollo 11 mission, with the reflection of Neil Armstrong visible in his face plate. Credit: NASA

Several more Apollo missions followed which expanded on the accomplishments of the Apollo-11 crew. The US and NASA would remain the only nation and space agency to successfully land astronauts on the Moon, an accomplishment that has not been matched to this day.

Today, multiple space agencies (and even private companies) are contemplating returning to the Moon. Between NASA, the European Space Agency (ESA), the Russian Space Agency (Roscosmos), and the Chinese National Space Administration (CNSA), there are several plans for crewed missions, and even the construction of permanent bases on the Moon.

We have written many great articles about the Moon here at Universe Today. Here’s Who Were the First Men on the Moon?, How Many People Have Walked on the Moon?, How Do We Know the Moon Landing Isn’t Fake?, Where Were You When Apollo 11 Landed on the Moon?, What Does The Apollo 11 Moon Landing Site Look Like Today?

Want more information about the Moon? Here’s NASA’s Lunar and Planetary Science page. And here’s NASA’s Solar System Exploration Guide.

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Sources:

The 2016 Nobel Prize In Physics: It’s Complicated

This year's Nobel Prize in physics highlights the complications of awarding breakthrough achievements. Credit: nobelprize.org

Update: This year’s Nobel Prize in Physics has been awarded to David J. Thouless (University of Washington), F. Duncan M. Haldane (Princeton University), and J. Michael Kosterlitz of Brown University for “theoretical discoveries of topological phase transitions and topological phases of matter”. One half of the prize was awarded to Thouless while the other half was jointly awarded to Haldane and Kosterlitz.

The Nobel Prize in physics is a coveted award. Every year, the prize is bestowed upon the individual who is deemed to have made the greatest contribution to the field of physics during the preceding year. And this year, the groundbreaking discovery of gravitational waves is anticipated to be the main focus.

This discovery, which was announced on February 11th, 2016, was made possible thanks to the development of the Laser Interferometer Gravitational-Wave Observatory (LIGO). As such, it is expected that the three scientists that are most responsible for the invention of the technology will receive the Nobel Prize for their work. However, there are those in the scientific community who feel that another scientist – Barry Barish – should also be recognized.

But first, some background is needed to help put all this into perspective. For starers, gravitational waves are ripples in the curvature of spacetime that are generated by certain gravitational interactions and which propagate at the speed of light. The existence of such waves has been postulated since the late 19th century.

LIGO's two facilities, located in . Credit: ligo.caltech.edu
LIGO’s two observatories, the located in Livingston, Louisiana; and Hanford, Washington. Credit: ligo.caltech.edu

However, it was not until the late 20th century, thanks in large part to Einstein and his theory of General Relativity, that gravitational-wave research began to emerge as a branch of astronomy. Since the 1960s, various gravitational-wave detectors have been built, which includes the LIGO observatory.

Founded as a Caltech/MIT project, LIGO was officially approved by the National Science Board (NSF) in 1984. A decade later, construction began on the facility’s two locations – in Hanford, Washington and Livingston, Louisiana. By 2002, it began to obtain data, and work began on improving its original detectors in 2008 (known as the Advanced LIGO Project).

The credit for the creation of LIGO goes to three scientists, which includes Rainer Weiss, a professor of physics emeritus at the Massachusetts Institute of Technology (MIT); Ronald Drever, an experimental physics who was professor emeritus at the California Institute of Technology and a professor at Glasgow University; and Kip Thorne, the Feynman Professor of Theoretical Physics at Caltech.

In 1967 and 68, Weiss and Thorne initiated efforts to construct prototype detectors, and produced theoretical work to prove that gravitational waves could be successfully analyzed. By the 1970s, using different methods, Weiss and Denver both succeeded in building detectors. In the coming years, all three men remained pivotal and influential, helping to make gravitational astronomy a legitimate field of research.

 A bird's eye view of LIGO Hanford's laser and vacuum equipment area (LVEA). The LVEA houses the pre-stabilized laser, beam splitter, input test masses, and other equipment. Credit: ligo.caltech.edu
LIGO Hanford’s laser and vacuum equipment area (LVEA), which houses the pre-stabilized laser, beam splitter, input test masses, and other equipment. Credit: ligo.caltech.edu

However, it has been argued that without Barish – a particle physicist at Caltech – the discovery would never have been made. Having become the Principal Investigator of LIGO in 1994, he inherited the project at a very crucial time. It had begun funding a decade prior, but coordinating the work of Wiess, Thorne and Drever (from MIT, Caltech and the University of Glasgow, respectively) proved difficult.

As such, it was decided that a single director was needed. Between 1987 and 1994, Rochus Vogt – a professor emeritus of Physics at Caltech – was appointed by the NSF to fill this role. While Vogt brought the initial team together and helped to get the construction of the project approved, he proved difficult when it came to dealing with bureaucracy and documenting his researchers progress.

As such, between 1989 through 1994, LIGO failed to progress technically and organizationally, and had trouble acquiring funding as well. By 1994, Caltech eased Vogt out of his position and appointed Barish to the position of director. Barish got to work quickly, making significant changes to the way LIGO was administered, expanding the research team, and developing a detailed work plan for the NSF.

Barish was also responsible for expanding LIGO beyond its Caltech and MIT constraints. This he did through the creation of the independent LIGO Scientific Collaboration (LSC), which gave access to outside researchers and institutions. This was instrumental in creating crucial partnerships, which included the UK Science and Technology Facilities Council, the Max Planck Society of Germany, and the Australian Research Council.

Artist's impression of how massive bodies (like our Sun) distort space time. Credit: T. Pyle/Caltech/MIT/LIGO Lab
Artist’s impression of how massive bodies (like our Sun) distort space time. Such bodies also create gravity waves when they accelerate through space and time. Credit: T. Pyle/Caltech/MIT/LIGO Lab

By 1999, construction had wrapped up on the LIGO observatories, and by 2002, they began taking their first bits of data. By 2004, the funding and groundwork was laid for the next phase of LIGO development, which involved a multi-year shut-down while the detectors were replaced with improved “Advanced LIGO” versions.

All of this was made possible by Barish, who retired in 2005 to head up other projects. Thanks to his sweeping reforms, LIGO got to work after an abortive start, began to produce data, procured funding, crucial partnerships, and now has more than 1000 collaborators worldwide, thanks to the LSC program he established.

Little wonder then why some scientists think the Nobel Prize should be split four-ways, awarding the three scientists who conceived of LIGO and the one scientist who made it happen. And as Barish himself was quoted as saying by Science:

“I think there’s a bit of truth that LIGO wouldn’t be here if I didn’t do it, so I don’t think I’m undeserving. If they wait a year and give it to these three guys, at least I’ll feel that they thought about it,” he says. “If they decide [to give it to them] this October, I’ll have more bad feelings because they won’t have done their homework.”

The approximate locations of the two gravitational-wave events detected so far by LIGO are shown on this sky map of the southern hemisphere. . Credit: LIGO/Axel Mellinger
The approximate locations of the two gravitational-wave events detected so far by LIGO are shown on this sky map of the southern hemisphere. . Credit: LIGO/Axel Mellinger

However, there is good reason to believe that the award will ultimately be split three ways, leaving Barish out. For instance, Weiss, Drever, and Thorne have been honored three times already this year for their work on LIGO. This has included the Special Breakthrough Prize in Fundamental Physics, the Gruber Cosmology Prize, and Kavli Prize in Astrophysics.

What’s more, in the past, the Nobel Prize in physics has tended to be awarded to those responsible for the intellectual contributions leading to a major breakthrough, rather than to those who did the leg work. Out of the last six Prizes issued (between 2010 and 2015), five have been awarded for the development of experimental methods, observational studies, and theoretical discoveries.

Only one award was given for a technical development. This was the case in 2014 where the award was given jointly to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura for “the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources”.

Basically, the Nobel Prize is a complicated matter. Every year, it is awarded to those who made a considerable contribution to science, or were responsible for a major breakthrough. But contributions and breakthroughs are perhaps a bit relative. Whom we choose to honor, and for what, can also be seen as an indication of what is valued most in the scientific community.

In the end, this year’s award may serve to highlight how significant contributions do not just entail the development of new ideas and methods, but also in bringing them to fruition.

Further Reading: Science, LIGO, Nobelprize.org

What is Carbon Dating?

Full length negatives of the shroud of Turin. Radiocarbon dating allowed for its true age to be determined. Credit: Wikipedia Commons

Here on Earth, Carbon is found in the atmosphere, the soil, the oceans, and in every living creature. Carbon 12 – aka. C-12, so-named because it has an atomic weight of 12 – is the most common isotope, but it is by no means the only one. Carbon 14 is another, an isotope of carbon that is produced when Nitrogen (N-14) is bombarded by cosmic radiation.

This process causes a proton to be displaced by a neutron, effectively turning atoms of Nitrogen it into an isotope of carbon – known as”radiocarbon”. It is naturally radioactive and unstable, and will therefore spontaneously decay back into N-14 over  a period of time. This property makes it especially useful in a process known as “radiocarbon dating”, or carbon dating for short.

Origin of Radiocarbon:

Radiocarbon enters the biosphere through natural processes like eating and breathing. Plants and animals absorb both C-12 and C-14 in the course of their natural lifetimes simply by carrying out these basic functions. When they die, they cease to consume them, and the isotope of C-14 begins to revert back to its Nitrogen state at an exponential rate due to its radioactive decay.

Comparing the remaining C-14 of a sample to that expected from atmospheric C-14 allows the age of the sample to be estimated. In addition, scientists know that the half-life of radiocarbon is 5,730 years. This means that it takes a sample of radiocarbon 5,730 years for half of it to decay back into nitrogen.

After about 10 half-lives, the amount of radiocarbon left becomes too minuscule to measure and so this technique isn’t particularly reliable for dating specimens which died more than 60,000 years ago – i.e. during the late Middle Paleolithic (aka. Old Stone Age) period.

History of Development:

Experiments that would eventually lead to carbon dating began in the 1939s, thanks to the efforts of the Radiation Laboratory at the University of California, Berkeley. At the time, researchers were attempting to determine if any of the elements common to organic matter had isotopes with half-lives long enough to be of value in biomedical research.

By 1940, the half-life of Carbon 14 was determined, as was the mechanism through which it was created (slow neutrons interacting with Nitrogen in the atmosphere). This contradicted previous work, which held that it was the product of deuterium (H², or heavy hydrogen) and Carbon 13.

A hydrogen atom is made up of one proton and one electron, but its heavy form, called deuterium, also contains a neutron. HDO or heavy water is rare compared to normal drinking water, but being heavier, more likely to stick around when the lighter form vaporizes into space. Credit: NASA/GFSC
A hydrogen atom is made up of one proton and one electron, but its heavy form, called deuterium, also contains a neutron. Credit: NASA/GFSC

During World War II, Willard Libby – a chemist and graduate of Berkeley – read a paper by W. E. Danforth and S. A. Korff (published in 1939) which predicted that C 14 would be created in the atmosphere due to interactions between nitrogen and cosmic rays. From this, Libby came up with the idea of measuring the decay of C 14 as a method of dating organic material.

In 1945, Libby moved to the University of Chicago, where he began the work that would lead to the development of radiocarbon dating. In 1946, he published a paper in which he speculated that C 14 might exist within organic material alongside other carbon isotopes.

After conducting experiments, which measured C-14 in methane derived from sewage samples, Libby and his colleagues were able to demonstrate that organic matter contained radioactive C-14. This was followed by experiments involving wood samples for the tombs of two Egyptian kings, for which the age was known.

Their results proved accurate, with allowances for a small margin of error, and were published in 1949 in the journal Science. In 1960, Libby received the Nobel Prize in Chemistry for this work. Since that time, carbon dating has been used in multiple fields of science, and allowed for key transitions in prehistory to be dated.

Diagram showing how radiocarbon dating works. Credit: howstuffworks.com
Diagram showing how radiocarbon dating works. Credit: howstuffworks.com

Limits of Carbon Dating:

Carbon dating remains limited for a number of reasons. First, there is the assumption that the ratio of C-12 to C-14 in the atmosphere has remained constant, when in fact, the ratio can be affected by a number of factors. For instance, C-14 production rates in the atmosphere, which in turn are affected by the amount of cosmic rays penetrating the Earth’s atmosphere.

This is itself affected by things like the Earth’s magnetic field, which deflects cosmic rays. Furthermore, precise measurements taken over the last 140 years have shown a steady decay in the strength of the Earth’s magnetic field. This means there’s been a steady increase in radiocarbon production (which would increase the ratio).

Another limitation is that this technique can only be applied to organic material such as bone, flesh, or wood, and can’t be used to date rocks directly. On top of that, the addition of Carbon 12 will throw off the ration, thus leading to inaccurate assessments of a sample’s age.

This is where anthropogenic factors come into play. Since fossil fuels have no Carbon 14 content, the burning of gasoline, oil, and other hydrocarbons – and in greater and greater quantity over the course of the past century and a half – has diluted the C-14 content of the atmosphere.

On the other hand, atmospheric testing of nuclear weapons during the 1950s and 1960s is likely to have increased the Carbon 14 content of the atmosphere. In fact, research has been conducted which suggests that nuclear tests may have doubled the concentration of C-14 in this time, compared to natural production by cosmic rays.

Nevertheless, it remains the most accurate means of dating the scientific community has discovered so far. Until such time that another method becomes available – and one that produces smaller margins of error – it will remain the method of choice for archeology, paleontology, and other branches of scientific research.

We have written many articles about Carbon Dating for Universe Today. Here’s How Do We Know How Old Everything Is?, How Old is the Universe?, How Old is the Solar System?, How Long has Humans been on Earth?

If you’d like more info on Carbon Dating, check out NASA’s Virtual Dating: Isochron and Radiocarbon – Geology Labs On-line, and here’s a link to USGS Radiometric Dating Page.

We’ve also recorded an entire episode of Astronomy Cast all about How Carbon Dating Works. Here’s Episode 122: How Old is the Universe? and Episode 164: Inside the Atom.

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