Astronomy Archives

November 13, 2014December 23, 2015 by Tim Reyes

China Reveals Designs for Mars Rover Mission

A mock-up of a future Chinese Martian rover was displayed at the International Industry Fair in Shanghai (Credit: South China Morning Post)

For many space-faring nations, ambitions for Mars run broad and deep. Now, add China to the list of countries with Mars in their sights. News reports from China disclosed that country is considering a future Mars rover mission, with a potential 2020 launch date. Additionally came other hints that China may be looking to develop a next-generation heavy-lift launch system.

This new project, while early in development, reveals how Chinese aspirations are growing rapidly. Human space flight successes have been followed by recent lunar mission successes of the Yutu lunar rover and the Chang’e-5 T1 test of a sample return mission. The Chinese Mars missions could influence future plans of ESA, India and NASA or more simply raise the urgency to execute missions in concept or early development without hesitation.

China View reporter Lai Yuchen is seen describing and pointing out the future Sino-Mars rover with plans for a 2020 launch coinciding with the NASA/JPL Mars 2020 rover mission . (Click still image for video Link) (Photo/Video Credit: China View)

The Mars rover mock-up display was presented at the aerospace show by China Aerospace Science and Technology Corporation (CASC). The design appears similar to the Yutu rover which landed successfully on the Moon late in 2013. While Yutu’s mobility system failed prematurely, many mission milestones were achieved.

The Mars rover design is significantly larger than Yutu but includes changes that can be attributed to the challenges of roving Mars at tens of millions of kilometers distance and under more gravitational force. The wheels are beefed up, since it must withstand more force and rugged martian terrain (gravity on Mars is 37% of the Earth’s in strength but 2.25 times the strength of gravity on the Moon’s surface.) The the solar panels are larger due to 1.) less sunlight at Mars – 35% to 50% of Earth’s, and 2.) more electrically demanding instruments.

The goals of the Chinese Mars rover will be to search for life and water. The NASA missions searching for indicators of habitable environments and for water has cost billions of dollars but the Chinese space program is operating on a fraction of what NASA’s annual budget is. Whereas the Chinese Mars program will be competing with the lunar program for government funds, it remains to be seen how quickly they can make progress and actually meet milestones for a 2020 launch date.

Besides video of the China View reporter presenting and discussing the Mars rover (link to photo above), the video also includes a simulation of the Chinese lunar sample return spacecraft, which is underdevelopment and was tested early this month during a the Chang’e-5 T1 circum-lunar mission that proved a small re-entry vehicle.

The future Chinese rover would be nearly as large as the MER rovers. Full scale models of all three NASA/JPL Mars rovers are shown here - Mars Pathfinder, MER and MSL in a JPL Mars yard with engineers. (Photo Credit: NASA/JPL) — The future Chinese rover would be nearly as large as the MER rovers. Full scale models of all three NASA/JPL Mars rovers are shown here – Mars Pathfinder, MER and MSL in a JPL Mars yard with engineers. (Photo Credit: NASA/JPL)

The actual dimensions of this rover were not reported but an estimate of the size can be determined by the size of the high-gain directional antenna. Assuming it is an X-Band dish, like the one on the MER Rovers and Curiosity, then this Sino-rover would be near the same size as the MER rovers – Spirit and Opportunity. The Sino-rover shares a six wheel design like MER and MSL rovers.

Other reports from the China Daily indicated that industry leaders in China are urging China’s space agency to develop a more powerful heavy-lift launch system. It could be used for the nation’s human spaceflight goals to send a space station in to orbit, as well as send missions to Mars and beyond.

“It is a must for us to develop a more powerful heavy-lift rocket if we want to reach and explore deep space,” Zhang Zhi, a senior rocket researcher at the China Academy of Launch Vehicle Technology the aerospace exhibition.

Plans also call for an orbiter to likely function as a communication relay as MGS, Mars Odyssey and MRO have done for the American rovers. Whether this would involve a single spacecraft such as the NASA Vikings or dual crafts such as the present American rovers with supporting orbiters is unknown. Given the successful landing of the Yutu rover encapsuled in a soft-lander, one might expect the same for the Chinese Mars rover rather than an airbag landing used by MER. Either way, they will be challenged by the seven minutes of terror just like the American rovers. They will have to solve for themselves the entry, descent and landing of a rover. Only American-made rovers have successfully landed on Mars; all Russian attempts have ended in failure.

The Chinese Lunar Sample Return mission is show in simulation in the China View video. This mission would pave the way for a Chinese Mars sample return by 2030. (Photo Credit: China View)

The presentation also stated future plans for a sample-return mission by 2030. If the first Chineses Mars rover lands successfully in 2020, it will join up to four active rovers on the surface. Curiosity, ExoMars (ESA/NASA), Mars Rover 2020 and MER Opportunity. Six years seems like a long time but MER’s Oppy is a proven trooper having lasted over ten years. Curiosity, barring the unexpected, might last beyond 2020. ExoMars and NASA’s 2020 rover are still in development phases. Using ExoMars or 2020, NASA has plans to recover collected samples from rovers and return them to Earth in the 2020s and possibly as soon as 2022.

References:

China unveils first Mars rover and exploration system for red planet
China Daily

November 13, 2014December 23, 2015 by Elizabeth Howell

Radio Galaxy With Black Hole Has ‘Fierce Electrical Thunderstorm’ Raging In Its Depths

Observations of the IC 310 radio galaxy have revealed the first lightning flashes observed from a black hole, astronomers say. Credit: Valencian Universities Network for the Promotion of Research, Development and Innovation (RUVID)

We know black holes are dangerous to people and galactic objects alike due to their immense gravity. But it turns out the galaxies that host supermassive black holes also have stormy interiors, at least according to one new study.

Scientists have found gamma-ray euptions emerging from the center of the IC 310 radio galaxy in Perseus — the strongest such variations in brightness ever found, they say — which they are comparing to a lightning storm.

It’s common for changes in brightness to happen in these galaxies as falling matter plunges into the black hole. The radio galaxies also produce jets that shoot matter away from the center at close to the speed of light.

Artist rendering of a supermassive black hole. Credit: NASA / JPL-Caltech.

What baffles researchers for IC 310 is how quickly they saw brightness shifts– on the order of five minutes, which is odd considering that the black hole’s event horizon (the point where there’s no way you’ll get out of there) requires 25 minutes to go across. This means the lightning is likely coming from a region that is smaller than the event horizon itself.

“We believe that in the black hole’s polar regions there are huge electric fields, which are able to accelerate fundamental particles at relativist speeds,” stated study leader Eduardo Ros, a researcher from the Max Planck Institute for Radio Astronomy and the Universitat de València.

“When they interact with others of lower energy, [they] are able to produce highly energized gamma rays,” he added. “We can imagine this process as a fierce electrical thunderstorm.”

Results of the study were published in the journal Science. Observatories participating included the Major Atmospheric Gamma-ray Imaging Cherenkov Telescopes (MAGIC) at La Palma in the Canary Islands, and the European Very Large Baseline Interferometer Network.

Source: Valencian Universities Network for the Promotion of Research, Development and Innovation (RUVID)

November 12, 2014December 23, 2015 by Elizabeth Howell

Uranus Bland? Nope, It’s A Stormy Planet With Interesting Insides

A composite image of Uranus in two infrared bands, showing the planet and its ring system. Picture taken by the Keck II telescope and released in 2007. Credit: W. M. Keck Observatory (Marcos van Dam)

Sometimes first impressions are poor ones. When the Voyager 2 spacecraft whizzed by Uranus in 1986, the close-up view of the gas giant revealed what appeared to a be a relatively featureless ball. By that point, scientists were used to seeing bright colors and bands on Jupiter and Saturn. Uranus wasn’t quite deemed uninteresting, but the lack of activity was something that was usually remarked upon when describing the planet.

Fast-forward 28 years and we are learning that Uranus is a more complex world than imagined at the time. Two new studies, discussed at an American Astronomical Society meeting today, show that Uranus is a stormy place and also that the images from Voyager 2 had more interesting information than previously believed.

Showing the value of going over old data, University of Arizona astronomer Erich Karkoschka reprocessed old images of Voyager 2 data — including stacking 1,600 pictures on top of each other.

He found elements of Uranus’ atmosphere that reveals the southern hemisphere moves differently than other regions in fellow gas giants. Since only the top 1% of the atmosphere is easily observable from orbit, scientists try to make inferences about the 99% that lie underneath by looking at how the upper atmosphere behaves.

“Some of these features probably are convective clouds caused by updraft and condensation. Some of the brighter features look like clouds that extend over hundreds of kilometers,” he stated in a press release.

“The unusual rotation of high southern latitudes of Uranus is probably due to an unusual feature in the interior of Uranus,” he added. “While the nature of the feature and its interaction with the atmosphere are not yet known, the fact that I found this unusual rotation offers new possibilities to learn about the interior of a giant planet.”

It’s difficult to get more information about the inner atmosphere without sending down a probe, but other methods of getting a bit of information include using radio (which shows magnetic field rotation) or gravitational fields. The university stated that Karkoschka’s work could help improve models of Uranus’ interior.

So that was Uranus three decades ago. What about today? Turns out that storms are popping up on Uranus that are so large that for the first time, amateur astronomers can track them from Earth. A separate study on Uranus shows the planet is “incredibly active”, and what’s more, it took place at an unexpected time.

Summer happened in 2007 when the Sun shone on its equator, which should have produced more heat and stormy weather at the time. (Uranus has no internal heat source, so the Sun is believed to be the primary driver of energy on the planet.) However, a team led by Imke de Pater, chair of astronomy at the University of California, Berkeley, spotted eight big storms in the northern hemisphere while looking at the planet with the Keck Telescope on Aug. 5 and 6.

Infrared images of Uranus showing storms at 1.6 and 2.2 microns obtained Aug. 6, 2014 by the 10-meter Keck telescope. Credit: Imke de Pater (UC Berkeley) & Keck Observatory images.

Keck’s eye revealed a big, bright storm that represented 30% of light reflected by the planet at a wavelength of 2.2 microns, which provides information about clouds below the tropopause. Amateurs, meanwhile, spotted a storm of a different sort. Between September and October, several observations were reported of a storm at 1.6 microns, deeper in the atmosphere.

“The colors and morphology of this [latter] cloud complex suggests that the storm may be tied to a vortex in the deeper atmosphere similar to two large cloud complexes seen during the equinox,” stated Larry Sromovsky, a planetary scientist at the University of Wisconsin, Madison.

What is causing the storms now is still unknown, but the team continues to watch the Uranian weather to see what will happen next. Results from both studies were presented at the Division for Planetary Sciences meeting of the American Astronomical Society in Tucson, Arizona today. Plans for publication and whether the research was peer-reviewed were not disclosed in press releases concerning the findings.

November 12, 2014December 23, 2015 by Bob King

Philae’s First Photos; Update on its Troubled Landing

Image from the Philae lander as it approached the surface. The dust-covered boulder at upper right is about 5 meters (16.4 feet) across. The dust might have originated through vaporization of ice on the boulder itself or deposited there by dust settling from jets elsewhere. Credit: ESA

First photo released of Comet 67P/C-G taken by Philae during its descent. The view is just 1.8 miles above the comet. Credit: ESA

Hey, we’re getting closer! This photo was taken by Philae’s ROLIS instrument just 1.8 miles (3 km) above the surface of 67P/Churyumov-Gerasimenko at 8:38 a.m. (CST) today. The ROLIS instrument is a down-looking imager that acquires images during the descent and doubles as a multi-wavelength close-up camera after the landing. The aim of the ROLIS experiment is to study the texture and microstructure of the comet’s surface. ROLIS (ROsetta Lander Imaging System) is a descent and close-up camera on the Philae lander.

I know, I know. You got a fever for more comet images the way Christopher Walken on Saturday Night Live couldn’t get enough cowbell.

Just to give you a flavor for the rugged landscape Philae was headed toward earlier today, this photo was taken by Rosetta at an altitude of 4.8 miles (7.7 km) from the comet's surface. Credit: ESA — Just for a little flavor of the rugged landscape Philae was headed toward earlier today, this photo was taken recently by Rosetta 4.8 miles (7.7 km) from the comet’s surface. Credit: ESA

Key scientists in a media briefing this afternoon highlighted the good news and the bad news about the landing. We reported earlier that both the harpoons and top thrusters failed to fire and anchor the lander to the comet. Yet land it did – maybe more than once! A close study of the data returned seems to indicate that Philae, without its anchors, may have touched the surface and then lifted off again, turning itself from the residual angular momentum left over after its flywheel was shut down. Stephan Ulamec, Philae Landing Manager, got a appreciative laugh from the crowd when he explained it this way: Maybe today we didn’t just land once. We landed twice!”

Stephan Ulamec, Philae Lander Manager. Credit: ESA

Telemetry from the probe has been sporadic. Data streams come in strong and then suddenly cut out only to return later. These fluctuations in the radio link obviously have the scientists concerned and as yet, there’s no explanation for them. Otherwise, Philae landed in splendid fashion almost directly at the center of its planned “error ellipse”.

Instruments on Philae are functioning normally and gathering data as you read this. Ulamec summed up the situation nicely: “It’s complicated to land and also complicated to understand the landing.”

Scientists and mission control will work to hopefully resolve the harpoon and radio link issues. The next live webcast begins tomorrow starting at 7 a.m. (CST). Although nothing definite was said, we may see more images arriving still today, so stop by later.

November 12, 2014December 23, 2015 by Bob King

Touchdown! Philae Successfully Lands on Rosetta’s Comet

Excitement ripples through the ESA control room with the news that Philae successfully landed on the comet this morning. Credit: ESA

We did it! We’re on the comet! At about 9:37 a.m. (CST) Philae touched down on Rosetta’s Comet. After traveling more than 315 million miles (508 million km) the lander’s signal arrived 28 minutes later with the fabulous news. Telemetry is trickling in and the lander’s in great health, but one small concern has arisen. We’ve just learned that the harpoons used to anchor Philae failed to fire. Mission control is considering whether to refire them to make sure the craft is stable.

Philae postcard. Hey, it made it - a huge congratulations to ESA. Credit: ESA — Philae is now at work on the comet after successfully harpooning itself to the surface. A huge congratulations to ESA! Credit: ESA

One might think that as long as the craft is sitting still on the comet, that will do. Well, maybe. Until it’s anchored, activity from nearby jets or even vaporizing ice beneath it could flip it over. After all, Philae only weighs a gram in 67P/C-G’s gravity field. The harpoons also house the instrument that measures surface density. Presumably, without them we won’t get that data.

ESA's version of a Swiss Army knife, Philae will now probe the comet on many levels. Credit: ESA — ESA’s version of a Swiss Army knife, Philae will now probe the comet on many levels. Credit: ESA

Now that Philae has reached its target, science will begin in earnest. Here’s an illustration that describes each of the probe’s instruments. Be sure to click to enlarge.

November 11, 2014December 23, 2015 by David Dickinson

Midway Between Storms: Our Guide to the 2014 Leonid Meteors

If there’s one meteor shower that has the potential to bring on a storm of epic proportions, it’s the Leonids. Peaking once every 33 years, these fast movers hail from the Comet 55P Temple-Tuttle, and radiate from the Sickle, or backwards “question mark” asterism in the constellation Leo. And although 2014 is an “off year” in terms of storm prospects, it’s always worth taking heed these chilly November mornings as we await the lion’s roar once again.

The prospects: 2014 sees the expected peak of the Leonids arriving around 22:00 Universal Time (UT) which is 5:00 PM EST. Locally speaking, a majority of meteor showers tend to peak in the early AM hours past midnight, as the observer’s location turns forward facing into the oncoming meteor stream. Think of driving in an early November snowstorm, with the car being the Earth and the flakes of snow as the oncoming meteors. And if you’ve (been fortunate enough?) to have never seen snow, remember that it’s the front windshield of the car going down the highway that catches all of the bugs!

This all means that in 2014, the Asian Far East will have an optimal viewing situation for the Leonids, though observers worldwide should still be vigilant. Of course, meteor showers never read online prognostications such as these, and often tend to arrive early or late. The Leonids also have a broad range of activity spanning November 6^th through November 30^th.

The November path of the radiant of the 2014 Leonids. Credit: Starry Night Education Software.

The predicted ideal Zenithal Hourly Rate for 2014 stands at about 15, which is well above the typical background sporadic rate, but lower than most years. Expect the actual sky position of the radiant and light pollution to lower this hourly number significantly. And speaking of light pollution, the Moon is a 21% illuminated waning crescent on the morning of November 17^th, rising at around 2:00 AM local in the adjacent constellation of Virgo.

The Leonids can, once every 33 years, produce a storm of magnificent proportions. The history of Leonid observation may even extend back as far as 902 A.D., which was recorded in Arab annals as the “Year of the Stars.”

But it was the morning of November 13^th, 1833 that really gained notoriety for the Leonids, and really kicked the study of meteor showers into high gear.

The night was clear over the U.S. Eastern Seaboard, and frightened townsfolk were awakened to moving shadows on bedroom walls. Fire was the first thing on most people’s minds, but they were instead confronted with a stunning and terrifying sight: a sky seeming to rain stars in every direction. Churches quickly filled up, as folks reckoned the Day of Judgment had come. The 1833 Leonid storm actually made later historical lists as one of the 100 great events in the United States for the 19^th century. The storm has also been cited as single-handedly contributing to the religious fundamentalist revivals of the 1830s. Poet Walt Whitman witnessed the 1833 storm, and the song The Stars Fell on Alabama by Frank Perkins was inspired by the event as well.

Live in Alabama? Then you may well possess a license plate that commemorates the 1833 Leonid Storm. Wikimedia Commons image in the Public Domain.

But not all were fearful. Astronomer Denison Olmsted was inspired to study the radiants and paths of meteor streams after the 1833 storm, and founded modern meteor science. The Leonids continued to produce storms at 33 year intervals, and there are still many observers that recall the spectacle that the Leonids produced over the southwestern U.S. back 1966, with a zenithal hourly rate topping an estimated 144,000 per hour!

We also have a personal fondness for this shower, as we were fortunate enough to witness the Leonids from the dark desert skies of Kuwait back in 1998. We estimated the shower approached a ZHR of about 900 towards sunrise, as a fireballs seemed to light up the desert once every few seconds.

The situation at 22:00 UT on November 17th, noting the direction of the Earth’s motion with relation to the predicted peak of the 2014 Leonid stream. Created using Stellarium.

The Leonids have subsided in recent years, and have fallen back below enhanced rates since 2002. Here’s the most recent ZHR levels as per the International Meteor Organization:

2009: ZHR=80.

2010: ZHR=32.

2011: ZHR=22.

2012: ZHR=48.

Note: 2013 the shower was, for the most part, washed out by the Full Moon.

But this year is also special for another reason.

Note that the 2014-2015 season marks the approximate halfway mark to an expected Leonid outburst around 2032. Comet 55P Tempel-Tuttle reaches perihelion on May 20^th, 2031, and if activity in the late 1990s was any indication, we expect the Leonids to start picking up again around 2030 onward.

A simulated storm on the morning of November 17th, 2032. Credit: Stellarium. — A simulated Leonid storm on the morning of November 17th, 2032. Credit: Stellarium.

Observing meteors is as simple as laying back and looking up. Be sure to stay warm, and trace the trail of any suspect meteor back to the Sickle to identify it as a Leonid. The Leonid meteors have one of the fastest approach velocities of any meteor stream at 71 kilometres per second, making for quick, fleeting passages in the pre-dawn sky. Brighter bolides may leave lingering smoke trails, and we like to keep a set of binoculars handy to examine these on occasion.

Looking to do some real science? You can document how many meteors you see per hour from your location and send this in to the International Meteor Organization, which tabulates and uses these volunteer counts to characterize a given meteor stream.

Leonids Credit: NASA — The 1997 Leonids as seen from space by the MSX satellite. Credit: NASA/JPL

And taking images of Leonid meteors is as simple as setting your DSLR camera on a tripod and taking long exposure images of the night sky. Be sure to use the widest field of view possible, and aim the camera about 45 degrees away from the radiant to nab meteors in profile. We generally shoot 30 second to 3 minute exposures in series, and don’t be afraid to experiment with manual F-stop/ISO combinations to get the settings just right for the local sky conditions. And be sure to carefully review those shots on the “big screen” afterwards… nearly every meteor we’ve caught in an image has turned up this way.

Don’t miss the 2014 Leonids. Hey, we’re half way to the start of the 2030 “storm years!”

November 10, 2014December 23, 2015 by Elizabeth Howell

‘Naked’ Comets Could Expose Solar System’s Ancient Origin Story

Two objects with comet-like orbits flew through the solar system in 2013 and 2014, but with little to no activity on their surfaces. At left is C/2013 P2 Pan-STARRS and at right, C/2014 S3 Pan-STARRS. Credit: University of Hawaii Institute for Astronomy

What’s a comet that doesn’t look like a comet? The question sounds contradictory, but astronomers believe these objects exist. As comets pass through the solar system, they bleed ice and dust as the Sun’s effects wash over their small bodies. Over time, some of the objects can keep going like ghost ships — just without the ices that used to produce a show.

There already is a class of objects called damocloids that are believed to be extinct comets, but scientists believe they have found something new with two mysterious visitors — what they call “naked” comets — from the outer Solar System.

The two objects originate from an area that astronomers term the Oort Cloud, a hypothetical collection of icy bodies that orbit as far away as 100,000 times the Earth-Sun distance (astronomical unit). Gravitational influences then kick the objects in towards the Sun and they commence orbits that can last millions of years.

When Jan Oort first proposed this concept in the 1950s, he said that some of the objects there could have only a tiny layer of ice that would immediately evaporate during the first pass in near the Sun. That’s what astronomers think they are seeing in objects C/2013 P2 Pan-STARRS and C/2014 S3 Pan-STARRS.

The familiar solar system with its 8 planets occupies a tiny space inside a large spherical shell containing trillions of comets - the Oort Cloud. Credit: Wikimedia Commons — The familiar solar system with its 8 planets occupies a tiny space inside a large spherical shell containing trillions of comets – the Oort Cloud. Credit: Wikimedia Commons

“Objects on long-period orbits like this usually exhibit cometary tails, for example Comet ISON and Comet Hale Bopp, so we immediately knew this object was unusual,” stated Karen Meech, an astronomer at the University of Hawaii at Manoa who led the research. “I wondered if this could be the first evidence of movement of solar system building blocks from the inner solar system to the Oort Cloud.”

The automated Pan STARRS1 survey telescope found C/2013 P2 in August 2013, with astronomers remarking its orbit resembled that of a comet. But, C/2013 P2’s surface was quiet. A second look the next month with the 8-meter Gemini North telescope in Hawaii revealed a little bit of light and a dusty tail. The object stayed at about the same brightness, even when it got to its closest approach to the Sun (2.8 AU) in February 2014.

After the comet swung around the Sun and telescopes could look at it again, examinations with the Gemini North telescope found something weird: the object’s spectrum looked red. This makes it look more like a Kuiper Belt object — something that roams in shallower waters in the Solar System, beyond Neptune’s orbit — than a typical comet or asteroid.

While results were still being analyzed, in September a NASA survey found an object with curiously similar properties: C/2014 S3. When it was found, the object had already passed its closest approach to the Sun in August. But from analyzing the orbit, the scientists saw it had come to only within 2 AU. Also, the first observations showed barely a tail at all.

Distribution of Kuiper belt objects (green), along with various other outer Solar System bodies, based on data from the Minor Planet Center. [Credit: Minor Planet Center; Murray and Dermott]

A closer examination with the Canada-France-Hawaii Telescope revealed a mystery: the spectrum was more blue than red, hinting at materials similar to what you would find in the inner Solar System. The team says this could be a new class of objects altogether.

“I’ll be thrilled if this object turns out to have a surface composition similar to asteroids in the inner part of the asteroid belt. If this is the case, it will be remarkable for a body found so far out in the Solar System,” stated Meech.

“There are several models that try to explain how the planets grew in the early Solar System, and some of these predict that material formed close to the sun could have been thrown outward into the outer Solar System and Oort Cloud, where it remains today. Maybe we are finally seeing that evidence.”

Results were presented today (Nov. 10) at the Division of Planetary Sciences meeting of the American Astronomical Society in Tucson, Arizona. A press release did not say if the research is peer-reviewed, or state publication plans.

Source: University of Hawaii Institute for Astronomy

November 10, 2014June 5, 2022 by Matt Williams

What Did Isaac Newton Discover?

Godfrey Kneller's 1689 portrait of Isaac Newton at age 46. Image credit: Isaac Newton Insitute

Isaac Newton – who lived from December 25th, 1642, to March 20th, 1727 – was an English scientist, mathematician, and “natural philosopher”. In his time, he played a vital role in the Scientific Revolution, helping to advance the fields of physics, astronomy, mathematics and the natural sciences. From this, he established a legacy that would dominate the sciences for the next three centuries.

In fact, the term “Newtonian” came to be used by subsequent generations to describe bodies of knowledge that owed their existence to his theories. And because of his extensive contributions, Sir Isaac Newton is regarded as one of the most influential scholars in the history of science. But what exactly did he discover?

Newton’s Three Laws of Motion:

For starters, his magnum opus – Philosophiæ Naturalis Principia Mathematica (“Mathematical Principles of Natural Philosophy”), which was first published in 1687 – laid the foundations for classical mechanics. In it, he formulated his Three Laws of Motion, which were derived from Johann Kepler’s Laws of Planetary Motion and his own mathematical description of gravity.

William Blake's Newton (1795), depicted as a divine geometer. Image Credit: William Blake Archive/Wikipedia — *William Blake’s* Newton (1795), depicting him as a divine geometer. Image Credit: William Blake Archive/Wikipedia

The first law, known as the “law of inertia”, states that: “An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force.” The second law states that acceleration is produced when a force acts on a mass – ergo, the greater the mass of the object, the greater the force required to accelerate it. The third and final law states that “for every action, there is an equal but opposite reaction”.

Universal Gravitation:

He also formulated his law of Universal Gravitation in the Principia, which states that every point mass attracts every single other point mass by a force pointing along the line intersecting both point. According to his calculations, this force is proportional to the product of the two masses and inversely proportional to the square of the distance between them. The formula for this theory can be expressed as:

$F = G frac{m_1 m_2}{r^2}$

Newton would go on to use these principles to account for the trajectories of comets, the tides, the precession of the equinoxes, and other astrophysical phenomena. This effectively removed the last doubts about the validity of the heliocentric model of the cosmos which argued that the Sun (not the Earth) was at the center of the planetary system. His work also demonstrated that the motion of objects on Earth and of celestial bodies could be described by the same principles.

*Sapling of the reputed original tree that inspired Sir Isaac Newton to consider gravitation. Credit: Wikipedia Commons/Loodog*

Though Newton’s inspiration for his theories on gravity are often attributed to the “Apple Incident” – i.e. where he watched an apple fall from a tree – the story is considered apocryphal by modern sources who argue that he came to his conclusions over time. However, Newton himself described the incident, and contemporaries of his defend this assertion.

Shape of the Earth:

Additional contributions include his prediction that the Earth was likely shaped as an “oblate spheroid” – i.e. a sphere that experienced flattening at the poles. This theory would later be vindicated by the measurements of Maupertuis, La Condamine, and others. This in turn helped convince most Continental European scientists of the superiority of Newtonian mechanics over the earlier system of Descartes.

In terms of mathematics, he contributed to the study of power series, generalized the binomial theorem to non-integer exponents, developed Newton’s method for approximating the roots of a function, and classified most of the cubic plane curves. He also shares credit with Gottfried Leibniz for the development of calculus.

These discoveries represented a huge leap forward for the fields of math, physics, and astronomy, allowing for calculations that more accurately modeled the behavior of the universe than ever before.

Optics:

In 1666, Newton began contributing to the field of optics, first by observing that color was a property of light by measuring it through a prism. From 1670 to 1672, he lectured at the University of Cambridge on optics and investigated the refraction of light, demonstrating that the multicolored spectrum produced by a prism could be recomposed into white light by a lens and a second prism.

*Sunlight passing through a prism. Image credit: NASA*

As a result of his research, he came to theorize that color is the result of objects interacting with already-colored light rather than objects generating the color themselves, which is known as Newton’s theory of color.

In addition, he concluded that the lens of any refracting telescope would suffer from the dispersion of light into colors (chromatic aberration). As a proof of the concept, he constructed a telescope using a mirror as the objective to bypass that problem. This was the first known functional reflecting telescope in existence, the design of which is now known as a Newtonian telescope.

Other Achievements:

He also formulated an empirical law of cooling, studied the speed of sound, and introduced the notion of a Newtonian fluid. This term is used to describe any fluid where the viscous stresses arising from its flow, at every point, are linearly proportional to the rate of change of its deformation over time.

Beyond his work in mathematics, optics and physics, he also devoted a significant amount of time studying Biblical chronology and alchemy, but most of his work in these areas remained unpublished until long after his death.

So what did Isaac Newton discover? Theories that would dominate the fields of science, astronomy, physics and the natural world for centuries to come. His ideas would go on to influence such luminaries as Joseph-Louis Lagrange and Albert Einstein, the latter of whom is the only scientists believed to have left a comparable legacy.

We have written many interesting articles about Sir Isaac Newton here at Universe Today. Here’s Who was Sir Isaac Newton?, What did Isaac Newton Invent?, Who Discovered Gravity?, What is Absolute Space?, What is the Gravitational Constant?

There are other resources on the internet if you want to learn more about Isaac Newton. This UK site has some great info on his discoveries. You can also check out the PBS website.

You can also check out Astronomy Cast. Episode 44 Einstein’s Theory of Relativity is particularly interesting.

Sources:

November 10, 2014December 23, 2015 by Shannon Hall

A Snapshot of a Galactic Crash

This image combines NASA/ESA Hubble Space Telescope observations with data from the Chandra X-ray Observatory. As well as the electric blue ram pressure stripping streaks seen emanating from ESO 137-001, a giant gas stream can be seen extending towards the bottom of the frame, only visible in the X-ray part of the spectrum. Credit: NASA, ESA, CXC

Some galaxies shine with a red ghostly glow. Once these galaxies stop forming new stars, they can only host long-lived stars with low masses and red optical colors. Astronomers often call these ghostly galaxies “red and dead.” But the basics behind why some form so quickly is still a mystery.

“It is one of the major tasks of modern astronomy to find out how and why galaxies in clusters evolve from blue to red over a very short period of time,” said lead author Michele Fumagalli from Durham University in a news release. “Catching a galaxy right when it switches from one to the other allows us to investigate how this happens.”

And that’s exactly what Fumagalli and colleagues did.

The team used ESO’s Multi Unit Spectroscopic Explorer (MUSE) instrument mounted on the 8-meter Very Large Telescope. With this instrument, astronomers collect 90,000 spectra every time they look at an object, allowing them to gain a detailed map of the object’s motion through space.

This chart shows the location of the distant galaxy ESO 137-001 in the constellation of Triangulum Australe (The Southern Triangle). This is a rich area of the sky close to the Milky Way, but this galaxy is faint and needs a large telescope to be visible. Credit: ESO, IAU and Sky & Telescope — The location of the distant galaxy ESO 137-001. Credit: ESO / IAU / Sky & Telescope

The target, ESO 137-001, is a spiral galaxy 200 million light-years away in the constellation better known as the Southern Triangle. But more importantly, it’s currently hurtling toward the Norma Cluster and embarking on a grand galactic collision.

ESO 137-001 is being stripped of most of its gas due to a process called ram-pressure stripping. As the galaxy falls into the galaxy cluster, it feels a headwind, much as a runner feels a wind on even the stillest day. At times this can compress the gas enough to spark star formation, but if it’s too intense then the gas is stripped away, leaving a galaxy that’s empty of the material needed to form new stars.

So the galaxy is in the midst of a brilliant transformation, changing from a blue gas-rich galaxy to a red gas-poor galaxy.

The observations show that the outskirts of the galaxy are already completely devoid of gas. Here the stars and matter are more thinly spread, and gravity has a relatively week hold over the gas. So it’s easier to push the gas away.

In fact, dragging behind the galaxy are 200,000 light-year-long streams of gas that have already been lost, making the galaxy look like a jellyfish trailing its tentacles through space. In these streamers, the gas is turbulent enough to compress small pockets of gas and therefore actually ignite star formation.

The center of the galaxy, however, is not yet devoid of gas because the gravitational pull is strong enough to hold out much longer. But it will only take time until all of the galactic gas is swept away, leaving ESO 137-001 red and dead.

Surprisingly the new MUSE observations show the gas trailing behind continues to rotate in the same way that the galaxy does. Furthermore, the rotation of stars at the center of the galaxy remains unhindered by the great fall.

Astronomers remain unsure why as this is only a snapshot of one galactic crash, but soon MUSE and other instruments will pry more out of the cosmic shadows.

The results will be published in the journal Monthly Notices of the Royal Astronomical Society and are available online.

November 10, 2014December 23, 2015 by Matt Williams

NASA’s Next Exoplanet Hunter Moves Into Development

A conceptual image of the Transiting Exoplanet Survey Satellite. Image Credit: MIT

NASA’s ongoing hunt for exoplanets has entered a new phase as NASA officially confirmed that the Transiting Exoplanet Survey Satellite (TESS) is moving into the development phase. This marks a significant step for the TESS mission, which will search the entire sky for planets outside our solar system (a.k.a. exoplanets). Designed as the first all-sky survey, TESS will spend two years of an overall three-year mission searching both hemispheres of the sky for nearby exoplanets.

Previous sky surveys with ground-based telescopes have mainly picked out giant exoplanets. In contrast, TESS will examine a large number of small planets around the very brightest stars in the sky. TESS will then record the nearest and brightest main sequence stars hosting transiting exoplanets, which will forever be the most favorable targets for detailed investigations. During the third year of the TESS mission, ground-based astronomical observatories will continue monitoring exoplanets identified by the TESS spacecraft.

“This is an incredibly exciting time for the search of planets outside our solar system,” said Mark Sistilli, the TESS program executive from NASA Headquarters, Washington. “We got the green light to start building what is going to be a spacecraft that could change what we think we know about exoplanets.”

“During its first two years in orbit, the TESS spacecraft will concentrate its gaze on several hundred thousand specially chosen stars, looking for small dips in their light caused by orbiting planets passing between their host star and us,” said TESS Principal Investigator George Ricker of the Massachusetts Institute of Technology..

Artistic representations of the only known planets around other stars (exoplanets) with any possibility to support life as we know it. Credit: Planetary Habitability Laboratory, University of Puerto Rico, Arecibo. — *Artistic representations of known exoplanets with any possibility to support life. Image Credit: Planetary Habitability Laboratory, University of Puerto Rico, Arecibo.*

All in all, TESS is expected to find more than 5,000 exoplanet candidates, including 50 Earth-sized planets. It will also find a wide array of exoplanet types, ranging from small, rocky planets to gas giants. Some of these planets could be the right sizes, and orbit at the correct distances from their stars, to potentially support life.

“The most exciting part of the search for planets outside our solar system is the identification of ‘earthlike’ planets with rocky surfaces and liquid water as well as temperatures and atmospheric constituents that appear hospitable to life,” said TESS Project Manager Jeff Volosin at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Although these planets are small and harder to detect from so far away, this is exactly the type of world that the TESS mission will focus on identifying.”

Now that NASA has confirmed the development of TESS, the next step is the Critical Design Review, which is scheduled to take place in 2015. This would clear the mission to build the necessary flight hardware for its proposed launch in 2017.

“After spending the past year building the team and honing the design, it is incredibly exciting to be approved to move forward toward implementing NASA’s newest exoplanet hunting mission,” Volosin said.

TESS is designed to complement several other critical missions in the search for life on other planets. Once TESS finds nearby exoplanets to study and determines their sizes, ground-based observatories and other NASA missions, like the James Webb Space Telescope, would make follow-up observations on the most promising candidates to determine their density and other key properties.

*The James Webb Space Telescope. Image Credit: NASA/JPL*

By figuring out a planet’s characteristics, like its atmospheric conditions, scientists could determine whether the targeted planet has a habitable environment.

“TESS should discover thousands of new exoplanets within two hundred light years of Earth,” Ricker said. “Most of these will be orbiting bright stars, making them ideal targets for characterization observations with NASA’s James Webb Space Telescope.”

“The Webb telescope and other teams will focus on understanding the atmospheres and surfaces of these distant worlds, and someday, hopefully identify the first signs of life outside of our solar system,” Volosin said.

TESS will use four cameras to study sections of the sky’s north and south hemispheres, looking for exoplanets. The cameras would cover about 90 percent of the sky by the end of the mission.

This makes TESS an ideal follow-up to the Kepler mission, which searches for exoplanets in a fixed area of the sky. Because the TESS mission surveys the entire sky, TESS is expected to find exoplanets much closer to Earth, making them easier for further study.

In addition, Ricker said TESS would provide precision, full-frame images for more than 20 million bright stars and galaxies.

“This unique new data will comprise a treasure trove for astronomers throughout the world for many decades to come,” Ricker said.

Now that TESS is cleared to move into the next development stage, it can continue towards its goal of being a key part of NASA’s search for life beyond Earth.

“I’m still hopeful that in my lifetime, we will discover the existence of life outside of our solar system and I’m excited to be part of a NASA mission that serves as a key stepping stone in that search,” Volosin said.

Further Reading: NASA