Astronomy Archives

September 15, 2016September 16, 2016 by Matt Williams

How High is Space?

Look up at the night sky, and what do you see? Space, glittering and gleaming in all its glory. Astronomically speaking, space is really quite close, lingering just on the other side of that thin layer we call an atmosphere. And if you think about it, Earth is little more than a tiny island in a sea of space. So it is quite literally all around us.

By definition, space is defined as being the point at which the Earth’s atmosphere ends, and the vacuum of space begins. But exactly how far away is that? How high do you need to travel before you can actually touch space? As you can probably imagine, with such a subjective definition, people tend to disagree on exactly where space begins.

Definition:

The first official definition of space came from the National Advisory Committee for Aeronautics (the predecessor to NASA), who decided on the point where atmospheric pressure was less than one pound per square foot. This was the altitude that airplane control surfaces could no longer be used, and corresponded to roughly 81 kilometers (50 miles) above the Earth’s surface.

*The Bell X-1, in which Chuck Yeager “broke” the sound barrier in 1947. Credit: NASA*

Any NASA test pilot or astronaut who crosses this altitude is awarded their astronaut wings. Shortly after that definition was passed, the aerospace engineer Theodore von Kármán calculated that above an altitude of 100 km, the atmosphere would be so thin that an aircraft would need to be traveling at orbital velocity to derive any lift.

This altitude was later adopted as the Karman Line by the World Air Sports Federation (Fédération Aéronautique Internationale, FAI). And in 2012, when Felix Baumgartner broke the record for the highest freefall, he jumped from an altitude of 39 kilometers (24.23 mi), less than halfway to space (according to NASA’s definition).

By the same token, space is often defined as beginning at the lowest altitude at which satellites can maintain orbits for a reasonable time – which is approximately 160 kilometers (100 miles) above the surface. These varying definitions are complicated when one takes the definition of the word “atmosphere” into account.

Earth’s Atmosphere:

When we talk about Earth’s atmosphere, we tend to think of the region where air pressure is still high enough to cause air resistance, or where the air is simply thick enough to breath. But in truth, Earth’s atmosphere is made up of five main layers – the Troposphere, the Stratosphere, the Mesosphere, the Thermosphere, and the Exosphere – the latter of which extend pretty far out into space.

Space Shuttle Endeavour sillouetted against the atmosphere. The orange layer is the troposphere, the white layer is the stratosphere and the blue layer the mesosphere.[1] (The shuttle is actually orbiting at an altitude of more than 320 km (200 mi), far above all three layers.) Credit: NASA — *Space Shuttle Endeavor silhouetted against Earth’s atmosphere. The orange layer is the troposphere, the white layer is the stratosphere and the blue layer the mesosphere. Credit: NASA*

The Thermosphere, the second highest layer of the atmosphere, extends from an altitude of about 80 km (50 mi) up to the thermopause, which is at an altitude of 500–1000 km (310–620 mi). The lower part of the thermosphere, – from 80 to 550 kilometers (50 to 342 mi) – contains the ionosphere, which is so named because it is here in the atmosphere that particles are ionized by solar radiation.

Hence, this is where the phenomena known as Aurora Borealis and Aurara Australis are known to take place. The International Space Station also orbits in this layer, between 320 and 380 km (200 and 240 mi), and needs to be constantly boosted because friction with the atmosphere still occurs.

The outermost layer, known as the exosphere, extends out to an altitude of 10,000 km (6214 mi) above the planet. This layer is mainly composed of extremely low densities of hydrogen, helium and several heavier molecules (nitrogen, oxygen, CO²). The atoms and molecules are so far apart that the exosphere no longer behaves like a gas and the particles constantly escape into space.

It is here that Earth’s atmosphere truly merges with the emptiness of outer space, where there is no atmosphere. Hence why the majority of Earth’s satellites orbit within this region. Sometimes, the Aurora Borealis and Aurora Australis occur in the lower part of the exosphere, where they overlap into the thermosphere. But beyond that, there is no meteorological phenomena in this region.

Interplanetary vs. Interstellar:

Another important distinction when discussing space is the difference between that which lies between planets (interplanetary space) and that which lies between star systems (interstellar space) in our galaxy. But of course, that’s just the tip of the iceberg when it comes to space.

If one were to cast the net wider, there is also the space which lies between galaxies in the Universe (intergalactic space). In all cases, the definition involves regions where the concentration of matter is significantly lower than in other places – i.e. a region occupied centrally by a planet, star or galaxy.

In addition, in all three definitions, the measurements involved are beyond anything that we humans are accustomed to dealing with on a regular basis. Some scientists believe that space extends infinitely in all directions, while others believe that space is finite, but is unbounded and continuous (i.e. has no beginning and end).

In other words, there’s a reason they call it space – there’s just so much of it!

Exploration:

The exploration of space (that is to say, that which lies immediately beyond Earth’s atmosphere) began in earnest with what is known as the “Space Age“, This newfound age of exploration began with the United States and Soviet Union setting their sights on placing satellites and crewed modules into orbit.

The first major event of the Space Age took place on October 4th, 1957, with the launch of Sputnik 1 by the Soviet Union – the first artificial satellite to be launched into orbit. In response, then-President Dwight D. Eisenhower signed the National Aeronautics and Space Act on July 29th, 1958, officially establishing NASA.

Immediately, NASA and the Soviet space program began taking the necessary steps towards creating manned spacecraft. By 1959, this competition resulted in the creation of the Soviet Vostok program and NASA’s Project Mercury. In the case of Vostok, this consisted of developing a space capsule that could be launched aboard an expendable carrier rocket.

Along with numerous unmanned tests, and a few using dogs, six Soviet pilots were selected by 1960 to be the first men to go into space. On April 12th, 1961, Soviet cosmonaut Yuri Gagarin was launched aboard the Vostok 1 spacecraft from the Baikonur Cosmodrome, and thus became the fist man to go into space (beating American Alan Shepard by just a few weeks).

On June 16th, 1963, Valentina Tereshkova was sent into orbit aboard the Vostok 6 craft (which was the final Vostok mission), and thus became the first woman to go into space. Meanwhile, NASA took over Project Mercury from the US Air Force and began developing their own crewed mission concept.

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

Designed to send a man into space using existing rockets, the program quickly adopted the concept of launching ballistic capsules into orbit. The first seven astronauts, nicknamed the “Mercury Seven“, were selected from from the Navy, Air Force and Marine test pilot programs.

On May 5th, 1961, astronaut Alan Shepard became the first American in space aboard the Freedom 7 mission. Then, on February 20th, 1962, astronaut John Glenn became the first American to be launched into orbit by an Atlas launch vehicle as part of Friendship 7. Glenn completed three orbits of planet Earth, and three more orbital flights were made, culminating in L. Gordon Cooper’s 22-orbit flight aboard Faith 7, which flew on May 15th and 16th, 1963.

In the ensuing decades, both NASA and Soviets began to develop more complex, long-range crewed spacecraft. Once the “Race to the Moon” ended with the successful landing of Apollo 11 (followed by several more Apollo missions), the focus began to shift to establishing a permanent presence in space.

For the Russians, this led to the continued development of space station technology as part of the Salyut program. Between 1972 and 1991, they attempted to orbit seven separate stations. However, technical failures and a failure in one rocket’s second stage boosters caused the first three attempts after Salyut 1 to fail or result in the station’s orbits decaying after a short period.

*Skylab, America’s First manned Space Station. Photo taken by departing Skylab 4 crew in Feb. 1974. Credit: NASA*

However, by 1974, the Russians managed to successfully deploy Salyut 4, followed by three more stations that would remain in orbit for periods of between one and nine years. While all of the Salyuts were presented to the public as non-military scientific laboratories, some of them were actually covers for the military Almaz reconnaissance stations.

NASA also pursued the development of space station technology, which culminated in May of 1973 with the launch of Skylab, which would remain America’s first and only independently-built space station. During deployment, Skylab suffered severe damage, losing its thermal protection and one of its solar panels.

This required the first crew to rendezvous with the station and conduct repairs. Two more crews followed, and the station was occupied for a total of 171 days during its history of service. This ended in 1979 with the downing of the station over the Indian Ocean and parts of southern Australia.

By 1986, the Soviets once again took the lead in the creation of space stations with the deployment of Mir. Authorized in February 1976 by a government decree, the station was originally intended to be an improved model of the Salyut space stations. In time, it evolved into a station consisting of multiple modules and several ports for crewed Soyuz spacecraft and Progress cargo spaceships.

The Mir Space Station and Earth limb observed from the Orbiter Endeavour during NASA's STS-89 mission in 1998. Credit: NASA — *The Mir Space Station and Earth limb observed from the Orbiter Endeavour during NASA’s STS-89 mission in 1998. Credit: NASA*

The core module was launched into orbit on February 19th, 1986; and between 1987 and 1996, all of the other modules would be deployed and attached. During its 15-years of service, Mir was visited by a total of 28 long-duration crews. Through a series of collaborative programs with other nations, the station would also be visited by crews from other Eastern Bloc nations, the European Space Agency (ESA), and NASA.

After a series of technical and structural problems caught up with the station, the Russian government announced in 2000 that it would decommission the space station. This began on Jan. 24th, 2001, when a Russian Progress cargo ship docked with the station and pushed it out of orbit. The station then entered the atmosphere and crashed into the South Pacific.

By 1993, NASA began collaborating with the Russians, the ESA and the Japan Aerospace Exploration Agency (JAXA) to create the International Space Station (ISS). Combining NASA’s Space Station Freedom project with the Soviet/Russian Mir-2 station, the European Columbus station, and the Japanese Kibo laboratory module, the project also built on the Russian-American Shuttle-Mir missions (1995-1998).

With the retirement of the Space Shuttle Program in 2011, crew members have been delivered exclusively by Soyuz spacecraft in recent years. Since 2014, cooperation between NASA and Roscosmos has been suspended for most non-ISS activities due to tensions caused by the situation in the Ukraine.

However, in the past few years, indigenous launch capability has been restored to the US thanks to companies like SpaceX, United Launch Alliance, and Blue Origin stepping in to fill the void with their private fleet of rockets.

The ISS has been continuously occupied for the past 15 years, having exceeded the previous record held by Mir; and has been visited by astronauts and cosmonauts from 15 different nations. The ISS program is expected to continue until at least 2020, but may be extended until 2028 or possibly longer, depending on the budget environment.

As you can clearly see, where our atmosphere ends and space begins is the subject of some debate. But thanks to decades of space exploration and launches, we have managed to come up with a working definition. But whatever the exact definition is, if you can get above 100 kilometers, you have definitely earned your astronaut wings!

We have written many interesting articles about space here at Universe Today. Here is Why is Space Black?, How Cold is Space?, Space Debris Illustrated: The Problem in Pictures, What is Interplanetary Space?, What is Interstellar Space?, and What is Intergalactic Space?

For more information, check out NASA Reveals Mysteries of Interstellar Space and this list of Deep Space Missions.

Astronomy Cast has episodes on the subject, like the Space Stations Series, Episode 82: Space Junk, Episode 281: Explosions in Space, Episode 303: Equilibrium in Space, and Episode 311: Sound in Space.

Sources:

September 15, 2016September 16, 2016 by Bob King

The Lowdown on September’s Harvest Moon

The Full Moon of August 18, 2016 - the “Sturgeon Moon” - rising amid cloud over a wheatfield. This is a 5-exposure stack blended with luminosity masks, and shot with the Canon 60Da and 135mm telephoto. — The Full Moon of August 18, 2016 rises amid cloud over a wheat field. Friday night will see the rising of the annual Harvest Moon. Credit: **Alan Dyer**

It’s that wonderful time of year again when the Harvest Moon teeters on the horizon at sunset. You can watch the big orange globe rise on Friday (Sept. 16) from your home or favorite open vista just as soon as the Sun goes down. Despite being one of the most common sky events, a Full Moon rise still touches our hearts and minds every time. No matter how long I live, there will never be enough of them.

Friday night's Harvest Moon rises around sunset in the faint constellation Pisces the fish. Two fists above and left of the Moon, look for the four stars that outline the massive asterism of Pegasus the flying horse. Stellarium — Friday night’s Harvest Moon rises around sunset in the faint constellation Pisces the fish. Watch for it to come up almost due east around the time of sunset. Once the sky gets dark, look two fists above and left of the Moon for the four stars that outline the spacious asterism of Pegasus the flying horse. Stellarium

To see a moonrise, the most important information you need is the time the moon pops up for your city, which you’ll find by using this Moonrise and Moonset calculator. Once you know when our neighborly night light rises, pre-arrange a spot you can walk or drive to 10-15 minutes beforehand. The waiting is fun. Who will see it first? I’ll often expect to see the Moon at a certain point along the horizon then be surprised it’s over there.

A photographer finds just the right spot in Duluth along Lake Superior to photograph the Full Moon rise. The flattened shape of the Moon is caused by the layer of denser air closer to the horizon refracting or bending the bottom half of the Moon more strongly than the thinner air n — A photographer finds just the right spot in Duluth along Lake Superior to photograph a rising Full Moon. The flattened shape of the Moon is caused by the layer of denser air closer to the horizon refracting or bending the bottom half of the Moon more strongly than the thinner air along the top limb. In effect, refraction “lifts” the bottom half of the Moon upward into the top to give it a squashed appearance. Once the Moon rises high enough so we see it through much thinner (less dense) air, refraction becomes negligible and the Moon assumes its more familiar circular shape. Credit: Bob King

Depending on how low to the horizon you can see, it’s possible, especially over water, to catch the first glimpse of lunar limb breaching the horizon. This still can be a tricky feat because the Moon is pale, and when it rises, shows little contrast against the still-bright sky. Since the Moon moves about one outstretched fist to the east (left in the northern hemisphere) each night, if you wait until one night after full phase, the Moon will rise in a much darker sky and appear in more dramatic contrast against the sky background.

As the Moon rises, we peer through hundreds of miles of the lower atmosphere, where the air is densest and dustiest. Aerosols scatter much of the blues and greens in moonlight away, leaving orange and red. Turbulence and varying air densities along the line of sight can create all manner of distortions of the lunar disk. This photo sequence showing an extraordinary moonset was taken from the shores of Garrison Lake in Port Orford, Oregon. The camera was facing west; looking across the lake, beyond the narrow foredune and out toward the Pacific Ocean. A very clear atmosphere enabled me to watch the Moon set all the way down to the horizon. The distortion that occurred as it descended was quite remarkable -- the Moon's shape was changing as fast as I could snap a picture. Credit: Randy Scholten — This photo sequence showing an extraordinary moonset taken from the shores of Garrison Lake in Port Orford, Oregon. “The distortion that occurred as it descended was quite remarkable — the Moon’s shape was changing as fast as I could snap a picture,” said photographer Randy Scholten. As the Moon rises, we peer through hundreds of miles of the lower atmosphere, where the air is densest and dustiest. Aerosols scatter much of the blues and greens in moonlight away, leaving orange and red. Turbulence and varying air densities along the line of sight can create all manner of distortions of the lunar disk. Credit: **Randy Scholten**

Look closely at the rising Moon with both naked eye and binoculars and you might just see a bit of atmospheric sorcery at work. Refraction, illustrated the icy moonrise image above, is the big one. It creates the squashed Moon shape. But more subtle things are happening that depend on how turbulent or calm the air is along your line of sight to our satellite.

Clouds add their own beauty and mystery to the rising Moon. Credit: Bob King

Rippling waves “sizzling” around the lunar circumference can be striking in binoculars though the effect is quite subtle with the naked eye. Much easier to see without any optical aid are the weird shapes the Moon can assume depending upon the state of the atmosphere. It can looked stretched out like a hot air balloon, choppy with a step-like outline around its bottom or top, square, split into two moons or even resemble a “mushroom cloud”.

If you make a point to watch moonrises regularly, you’ll become acquainted as much with Earth’s atmosphere as with the alien beauty of our sole satellite.

This Full Moon is special in at least two ways. First, it will undergo a penumbral eclipse for skywatchers across eastern Europe, Africa, Asia and Australia. Observers there should watch a dusky gray shading over the upper or northern half of the Moon around the time of maximum eclipse. The link will take you to Dave Dickinson’s excellent article that appeared earlier here at Universe Today.

The angle of the moon’s path to the horizon makes all the difference in moonrise times. At full phase in spring, the path tilts steeply southward, delaying successive moonrises by over an hour. In September, the moon’s path is nearly parallel to the horizon with successive moonrises just 20+ minutes apart. Times are shown for the Duluth, Minn. region. Illustration: Bob King — The angle of the moon’s path to the horizon makes all the difference in moonrise times. At full phase in spring, the path tilts steeply southward, delaying successive moonrises by over an hour. In September, the moon’s path is nearly parallel to the horizon with successive moonrises just 20+ minutes apart. Times shown are for illustration only — so you can see the dramatic different in rise times — and don’t refer necessarily to Friday night’s moonrise. Illustration: Bob King

In the northern hemisphere, September’s Full Moon is named the Harvest Moon, defined as the Full Moon closest to the autumnal equinox, which occurs at 9:21 a.m. CDT (14:21 UT) on the 22nd. Normally, the Moon rises on average about 50 minutes later each night as it moves eastward along its orbit. But at Harvest Moon, successive moonrises are separated by a half-hour or less as viewed from mid-northern latitudes. The short gap of time between between bright risings gave farmers in the days before electricity extra light to harvest their crops, hence the name.

Use your imagination and you can see any of several figures in the Full Moon composed of contrasting maria and highlands.

Why the faster-than-usual moonrises? Every September, the Full Moon’s nightly travels occur at a shallow angle to the horizon; as the moon scoots eastward, it’s also moving northward this time of year as shown in the illustration above. The northern and eastward motions combine to make the Moon’s path nearly level to the horizon. For several nights in a row, it only takes a half-hour for the Earth’s rotation to carry the Moon up from below the horizon. In spring, the angle is steep because the Moon is then moving quickly southward along or near the ecliptic, the path it takes around the sky. Rising times can exceed an hour.

As you gaze at the Moon over the next several nights, take in the contrast between its ancient crust, called the lunar highlands, and the darker seas (also known as maria, pronounced MAH-ree-uh). The crust appears white because it’s rich in calcium and aluminum, while the maria are slightly more recent basaltic lava flows rich in iron, which lends them a darker tone. Thanks to these two different types of terrain it’s easy to picture a male or female face or rabbit or anything your imagination desires.

Happy moongazing!

September 14, 2016April 8, 2018 by Nancy Atkinson

At ISO 400,000, This 6-Minute Film Shows Why We Love the Night Sky

The pursuit of the night sky is ongoing for amateur astronomers. Credit and copyright: Ben Canales.

Obviously, you’ve seen timelapse videos of the night sky because we share them here on Universe Today all the time. But you’ve probably not seen a video like this one before. This one isn’t a timelapse, and you’ll see the night sky in all its splendor, in real time.

“I think this one may be the beginning of something damn interesting,” said filmmaker Ben Canales, who along with cohort John Waller of Uncage The Soul Productions, shot this video with new low-light technology. Using the new Canon MH20f-SH, which has the capability of shooting at 400,000 ISO, they were able to “film in the quiet moments that have been impossible to capture until now.”

“Since 2013, I’ve been tinkering with all sorts of camera/lens/software combinations trying to move beyond a long exposure still to real time video of the stars,” Canales said on Facebook. “Sooner or later, we have to move beyond a frozen photo of the stars to hear, see, feel what it is really like being out there!”

In addition to showcasing this wonderful new low-light shooting, Infinity² really captures the emotional side of amateur astronomy and the beauty of being under the night sky. He took a group of high school students out to witness the Perseid Meteor Shower in Oregon, and the students got together with the Oregon Star Party. Together, they answer the simple question “What do you feel?”

As Canales says, “Something internal and personal draws us out to the night sky.”

Check out more on Uncage The Soul Productions, Canales’ astrophoto website and Facebook.

Still image from the film Infinity ². Image Courtesy Ben Canales. — Still image from the film Infinity². Image Courtesy Ben Canales.

Infinity ² from Uncage the Soul Productions on Vimeo.

September 14, 2016February 11, 2017 by Matt Williams

What is the Weather like on Jupiter?

Jupiter's Great Red Spot or GRS - taken by Hubble on April 21, 2014. Image Credit:

Welcome to a new series here at Universe Today! In this segment, we will be taking a look at the weather on other planets. First up, we take a look at the “King of Planets” – Jupiter!

One of the most obvious facts about the gas giant Jupiter is its immense size. With a mean radius of 69,911 ± 6 km (43441 mi) and a mass of 1.8986 × 10²⁷ kg, Jupiter is almost 11 times the size of Earth, and just under 318 times Earth’s massive. But this “go big or go home” attitude extends far beyond the planet’s size.

When it comes to weather patterns, Jupiter is also an exercise in extremes. The planet experiences storms that can grow to thousands of kilometers in diameter in the space of a few hours. The planet also experiences windstorms, lightning, and auroras in some areas. In fact, the weather on Jupiter is so extreme that it can be seen from space!

Jupiter’s Atmosphere:

Jupiter is composed primarily of gaseous and liquid matter. It is the largest of the gas giants, and like them, is divided between a gaseous outer atmosphere and an interior that is made up of denser materials. It’s upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by percent volume of gas molecules, and approx. 75% hydrogen and 24% helium by mass, with the remaining one percent consisting of other elements.

This view compares a lucky imaging view of Jupiter from VISIR (left) at infrared wavelengths with a very sharp amateur image in visible light from about the same time (right). Credit: ESO/L.N. Fletcher/Damian Peach — *This view compares a “lucky imaging” view of Jupiter from VISIR (left) at infrared wavelengths with a very sharp amateur image in visible light (right). Credit: ESO/L.N. Fletcher/Damian Peach*

The atmosphere contains trace amounts of methane, water vapor, ammonia, and silicon-based compounds as well as trace amounts of benzene and other hydrocarbons. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. Crystals of frozen ammonia have also been observed in the outermost layer of the atmosphere.

Jupiter is perpetually covered with clouds that are composed of these ammonia crystals, and possibly ammonium hydrosulfide. These clouds are located in the tropopause and are arranged into bands of different latitudes, known as “tropical regions”. The cloud layer is only about 50 km (31 mi) deep, and consists of at least two decks of clouds: a thick lower deck and a thin clearer region.

These clouds are also what gives the planet is banded appearance, with clouds of yellow, brown and white circling the surface rapidly. These bands are produced by air flowing in different directions at various latitudes. Lighter-hued areas where the atmosphere rises are called zones. Darker regions where air falls are called belts. When these opposing flows interact, storms and turbulence appear (aka. “zonal jets”).

The Great Red Spot:

As noted already, Jupiter experiences violent storms, which often take the form of zonal jets. In these weather fronts, wind speeds of 100 m/s (360 km/h) are common. But wind storms on the mighty planet can reach as high as 620 kph (385 mph). These storms can form within hours and become thousands of kilometers in diameter overnight.

The Juno spacecraft isn't the first one to visit Jupiter. Galileo went there in the mid 90's, and Voyager 1 snapped a nice picture of the clouds on its mission. Image: NASA — *The Juno spacecraft isn’t the first one to visit Jupiter. Galileo went there in the mid 90’s, and Voyager 1 snapped a nice picture of the clouds on its mission. Image: NASA*

One storm, the Great Red Spot, has been raging since at least the late 1600s – when Italian astronomer Giovanni Cassini made the first recorded observation of it. The storm has been shrinking and expanding throughout its history; but in 2012, it was suggested that the Giant Red Spot might eventually disappear.

This storm is one of the best known features in the Solar System. It is located 22° south of the equator and reaching sizes of up to 40,000 km across, it is larger in diameter than Earth. The storm rotates in a counter-clockwise motion, making it an anti-cyclonic storm.

It rotates differently than the rest of the atmosphere: sometimes faster and sometimes slower. During its recorded history it has traveled several times around the planet relative to any fixed position below it.

Meteorological Phenomena:

Jupiter also experience weather phenomena that are similar to those of Earth. These lightning storms, which have been detected in Jupiter’s atmosphere. Scientists believe that these may be due to a thin layer of water clouds underlying the ammonia layer.

Composite images from the Chandra X-Ray Observatory and the Hubble Space Telescope show the hyper-energetic x-ray auroras at Jupiter. The image on the left is of the auroras when the coronal mass ejection reached Jupiter, the image on the right is when the auroras subsided. The auroras were triggered by a coronal mass ejection from the Sun that reached the planet in 2011. Image: X-ray: NASA/CXC/UCL/W.Dunn et al, Optical: NASA/STScI — Composite images from the Chandra X-Ray Observatory and the Hubble Space Telescope show the hyper-energetic x-ray auroras at Jupiter. Image: X-ray: NASA/CXC/UCL/W.Dunn et al, Optical: NASA/STScI

The presence of this water layer (and it’s polarity) would create the charge separation needed for lightning to occur. Observations of these electrical discharges indicate that they can be up to a thousand times as powerful as those observed here on the Earth.

Like Earth, Jupiter also experiences auroras near its northern and southern poles. But on Jupiter, the auroral activity is much more intense and rarely ever stops. The intense radiation, Jupiter’s powerful magnetic field, and the abundance of material from Io’s volcanoes that react with Jupiter’s ionosphere, create a light show that is truly spectacular.

What it comes down to is that Jupiter experiences weather that is similar to what we experience here on Earth. This includes wind storms, lightning, and auroras in both the northern and southern polar regions. The only difference is, in Jupiter’s case, the size and scale of the weather is much, much larger!

On Jupiter, as with everything else on the “King of Planets”, the weather is the result of titanic forces that produce some seriously powerful results. If any of these were to happen here on Earth, the results would be disasterous!

We have written many interesting articles about Jupiter here at Universe Today. Here’s Ten Interesting Facts About Jupiter, How Long Does it take to get to Jupiter?, How Much Bigger is Jupiter than Earth?, How Strong is Jupiter’s Gravity?, and Jupiter Compared to Earth.

For more information, check out NASA’s Solar System Exploration – Jupiter, and the facts about Jupiter from Space Facts.

Astronomy Cast also has episodes dedicated to Jupiter – Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Sources:

September 14, 2016October 5, 2016 by Matt Williams

Get That Geologist A Flight Suit!

Future missions to Mars and other locations in the Solar System may depend heavily on the skills of planetary geologists. Credit: NASA Ames Research Center

In the coming decades, the world’s largest space agencies all have some rather big plans. Between NASA, the European Space Agency (ESA), Roscosmos, the Indian Space Research Organisation (ISRO), or the China National Space Administration (CNSA), there are plans to return to the Moon, crewed missions to Mars, and crewed missions to Near-Earth Objects (NEOs).

In all cases, geological studies are going to be a major aspect of the mission. For this reason, the ESA recently unveiled a new training program known as the Pangaea course, a study program which focuses on identifying planetary geological features. This program showcases just how important planetary geologists will be to future missions.

Pangaea takes its name from the super-continent that that existed during the late Paleozoic and early Mesozoic eras (300 to 175 million years ago). Due to convection in Earth’s mantle, this continent eventually broke up, giving rise to the seven continents that we are familiar with today.

The super-continent Pangea during the Permian period (300 - 250 million years ago). Credit: NAU Geology/Ron Blakey — *The super-continent Pangea during the Permian period (300 – 250 million years ago). Credit: NAU Geology/Ron Blakey*

Francesco Sauro – a field geologist, explorer and the designer of the course – explained the purpose of Pangaea in an ESA press release:

“This Pangaea course – named after the ancient supercontinent – will help astronauts to find interesting rock samples as well as to assess the most likely places to find traces of life on other planets. We created a course that enables astronauts on future missions to other planetary bodies to spot the best areas for exploration and the most scientifically interesting rocks to take samples for further analysis by the scientists back on Earth.”

This first part of the course will take place this week, where astronaut trainer Matthias Maurer and astronauts Luca Parmitano and Pedro Duque will be learning from a panel of planetary geology experts. These lessons will include how to recognize certain types of rock, how to draw landscapes, and the exploration of a canyon that has sedimentary features similar to the ones observed in the Murray Buttes region, which was recently imaged by the Curiosity rover.

The geology panel will include such luminaries as Matteo Messironi (a geologist working on the Rosetta and ExoMars missions), Harald Hiesinger (an expert in lunar geology), Anna Maria Fioretti (a meteorite expert), and Nicolas Mangold (a Mars expert currently working with NASA’s Curiosity team).

Rock samples on display at ESA's Pangaea training for astronauts in identifying planetary geological features for future missions to the Moon, Mars and asteroids. Credit: ESA/L. Bessone — Rock samples on display at ESA’s Pangaea training course, which is intended to help astronauts in identify planetary geological features for future missions to the Moon, Mars and asteroids. Credit: ESA/L. Bessone

Once this phase of the course is complete, a series of field trips will follow to locations that were chosen because their geological features resemble those of other planets. This will include the town of Bressanone in northeastern Italy, which lies a few kilometers outside of the Brenner Pass (the part of the Alps that lies between Italy and Austria).

In many ways, the Pangaea course picks up where the Cooperative Adventure for Valuing and Exercising Human Behaviour and Performance Skills (CAVES) program left off. For several years now, the ESA has been conducting training missions in underground caverns in order to teach astronauts about working in challenging environments.

This past summer, the latest program involved a team of six international astronauts spending two weeks in a cave network in Sardinia, Italy. In this environment, 800-meters (2625 ft) beneath the surface, the team carried out a series of research and exploration activities designed to recreate aspects of a space expedition.

As the teams explore the caves of Sardinia, they encountered caverns, underground lakes and examples of strange microscopic life – all things they could encounter in extra-terrestrial environments. While doing this, they also get the change to test out new technologies and methods for research and experiments.

*Sedimentary outcroppings in the Bressanoe region (left), compared to sedimentary deposits in the Murray Buttes region on Mars (right). Credit: ESA/I. Drozdovsky (left); NASA (right)*

In a way that is similar to expeditions aboard the ISS, the program was designed to teach an international team of astronauts how to address the challenges of living and working in confined spaces. These include limited privacy, less equipment for hygiene and comfort, difficult conditions, variable temperatures and humidity, and extremely difficult emergency evacuation procedures.

Above all, the program attempts to foster teamwork, communication skills, decision-making, problem-solving, and leadership. This program is now an integral part of the ESA’s astronaut training and is conducted once a year. And as project leader Loredana Bessone explained, the Pangaea course fits with the aims of the CAVES program quite well.

“Pangaea complements our CAVES underground training,” she said. “CAVES focuses on team behaviour and operational aspects of a space mission, whereas Pangaea focuses on developing knowledge and skills for planetary geology and astrobiology.”

From all of these efforts, it is clear that the ESA, NASA and other space agencies want to make sure that future generations of astronauts are trained to conduct field geology and will be able to identify targets for scientific research. But of course, understanding the importance planetary geology in space exploration is not exactly a new phenomenon.

The six-member CAVES team in Sardinia, Italy, observing an underground pool. Credit: ESA/V.Crobu — *The six-member CAVES team in Sardinia, Italy, observing an underground pool. Credit: ESA/V. Crobu*

In fact, the study of planetary geology is rooted in the Apollo era, when it became a field separate from other fields of geological research. And geology experts played a very pivotal role when it came to selecting the landing sites of the Apollo missions. As Emily Lakdawalla, the Senior Editor of The Planetary Society (and a geologist herself), told Universe Today in a phone interview:

“The Apollo astronauts received training in field geology before they went to the Moon. Jim Head at Brown University, who was my advisor, was one person who provided that training. Before there were missions, the Lunar Orbiter program returned photos that geologists used to map the surface of the Moon and find good landing sites.”

This tradition is being carried on today with instruments like the Mars Global Surveyor. Before the Spirit and Opportunity rovers were deployed to the Martian surface, NASA scientists studied images taken by this orbiter to determine which potential landing sites would prove to be the valuable for conducting research.

And thanks to the experience gained by the Apollo missions and improvements made in both technology and instrumentation, the process has become much more sophisticated. Compared to the Apollo-era, today’s NASA mission planners have much more detailed information to go on.

*Moon rocks from the Apollo 11 mission. Credit: NASA*

“These days, the orbiter photos have such high resolutions that its just like having aerial photographs, which is something Earth geologists have always used as a tool to scope out an area before going to study it,” Lakdawalla said. “With these photos, we can map out an area in detail before we send a rover, and determine where the most high-value samples will be.”

Looking ahead, everything that’s learned from sending astronauts to the Moon – and from the study of the lunar rocks they brought back – is going to play a vital role when it comes time to explore Mars, go back to the Moon, and investigate NEOs. As Lakdawalla explained, in each case, the purpose of the geological studies will be a bit different.

“The goal in obtaining samples from the Moon was about understanding the chronology of the Moon. The timescale we have developed for the Moon are anchored in the Apollo samples. But we think that the samples have been sampling one major impact – the Imbrium impact. The next Moon samples will attempt to sample other time periods so we can determine if our time scales are correct.”

“On Mars, the questions is, ‘what are the history of water on Mars’. You try to find rocks from orbit that will answer that questions – rocks that have either been altered by water or formed in water. And that is how you select your landing zone.”

And with future missions to NEOs, astronauts will be tasked with examining geological samples which date back to the formation of the Solar System. From this, we are likely to get a better understanding of how our Solar System formed and evolved over the many billion years it has existed.

Clearly, it is a good time to be a geologist, as their expertise will be called upon for future missions to space. Hope they like tang!

Further Reading: ESA, CSA

September 13, 2016October 5, 2016 by Evan Gough

Hubble Images Three Debris Disks Around G-type Stars

An image of the circum-stellar disk around HD 207129. The three circled objects are background objects and part of the disk. Image: Hubble Space Telescope, Glenn Schneider et al 2016. — An image of the circum-stellar disk around HD 207129. The three circled objects are background objects and are not part of the disk. Image: Hubble Space Telescope, Glenn Schneider et al 2016.

A team using the Hubble Space Telescope has imaged circumstellar disk structures (CDSs) around three stars similar to our Sun. The stars are all G-type solar analogs, and the disks themselves share similarities with our Solar System’s own Kuiper Belt. Studying these CDSs will help us better understand their ring-like structure, and the formation of solar systems.

The team behind the study was led by Glenn Schneider of the Seward Observatory at the University of Arizona. They used the Hubble’s Space Telescope Imaging Spectrograph to capture the images. The stars in the study are HD 207917, HD 207129, and HD 202628.

Theoretical models of circumstellar disk dynamics suggest the presence of CDSs. Direct observation confirms their presence, though not many of these disks are within observational range. These new deep images of three solar analog CDSs are important. Studying the structure of these rings should lead to a better understanding of the formation of solar systems themselves.

A is the observed image of HD 207917. B is the best-fit debris ring model of the same star. Image: Hubble, G. Schneider et. al. 2016.

Debris disks like these are separate from protoplanetary disks. Protoplanetary disks are a mixture of both gas and dust which exist around younger stars. They are the source material out of which planetesimals form. Those planetesimals then become planets.

Protoplanetary disks are much shorter-lived than CDSs. Whatever material is left over after planet formation is typically expelled from the host solar system by the star’s radiation pressure.

In circumstellar debris disks like the ones imaged in this study, the solar system is older, and the planets have already formed. CDSs like these have lasted this long by replenishing themselves. Collisions between larger bodies in the solar system create more debris. The resulting debris is continually ground down to smaller sizes by repeated collisions.

This process requires gravitational perturbation, either from planets in the system, or by binary stars. In fact, the presence of a CDSs is a strong hint that the solar system contains terrestrial planets.

A circumstellar disk of debris around a mature stellar system could indicate the presence of Earth-like planets. Credit: NASA/JPL

The three disks in this study were viewed at intermediate inclinations. They scatter starlight, and are more easily observed than edge-on disks. Each of the three circumstellar disk structures possess “ring-like components that are more massive analogs of our solar system’s Edgeworth–Kuiper Belt,” according to the study.

The study authors expect that the images of these three disk structures will be studied in more detail, both by themselves and by others in future research. They also say that the James Webb Space Telescope will be a powerful tool for examining CDSs.

September 12, 2016November 21, 2016 by Tammy Plotner

Messier 23 – The NGC 6494 Open Star Cluster

Messier 23, Messier 21, Trifid Nebula (M20) and Omega Nebula (M17). Credit: Wikisky

Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the Messier 23 open star cluster. Enjoy!

Back in the 18th century, famed French astronomer Charles Messier noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of these objects so that other astronomers wouldn’t make the same mistake. Consisting of 100 objects, the Messier Catalog has come to be viewed as a major milestone in the study of Deep Space Objects.

One of these objects is Messier 23 (aka. NGC 6494), a large open star cluster that is located in the constellation Sagittarius. Given its luminosity, it can be found quite easily in the rich star fields of the summer Milky Way using small telescopes and even binoculars.

Description:

Located some 2,150 light years (659 Parsecs) away from Earth, this vast cloud of 176 confirmed stars stretches across 15 to 20 light years of space. At an estimated 220 to 300 million years old, Messier 23 is on the “senior citizen” list of galactic open clusters in our galaxy. At this age, its hottest stars reach spectral type B9, and it even contains a few blue straggler candidates.

Messier 23. Atlas Image mosaic obtained as part of the Two Micron All Sky Survey (2MASS), a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. — *Mosaic image obtained as part of the Two Micron All Sky Survey (2MASS). Credit: UofM/IPAC/Caltech/NASA/NSF*

Given that M23 has spent many centuries sweeping through the interstellar medium, astronomers have wondered how this would affect its metal content. Using UBV photometry, astronauts examined the metallicity of M23, and determined that it had no discernible effect. As W.L. Sanders wrote of the cluster in 1990:

“UBV photometric observations of 176 stars in the galactic cluster NGC 6494 are presented and analyzed. The effect of a gas poor environment on the metal abundance of NGC 6494 is studied. It is determined that the metallicity of NGC 6494, which has a delta(U – B) value = + 0.02, is not affected by the interarm region in which it dwelled.”

At the same time, astronomers have discovered that some of M23’s older stars – the red giants – are suffering mass loss. As G. Barbaro (et al.) of the Istituto di Fisica dell’Universita put it in 1969:

“A statistical research on evolved stars beyond hydrogen exhaustion is performed by comparing the H-R diagrams of about 60 open clusters with a set of isochronous curves without mass loss derived from Iben’s evolutionary tracks and time scales for Population I stars. Interpreting the difference in magnitude between the theoretical positions thus calculated and the observed ones as due to mass loss, when negative, the results indicate that this loss may be conspicuous only for very massive and red stars. However, a comparison with an analogous work of Lindoff reveals that the uncertainties connected with the bolometric and color corrections may invalidate by a large amount the conclusions which might be drawn from such research.”

Close-up image of the core of M23, showing some of its brightest member stars. Credit: Sharp/NOAO/AURA/NSF — *Close-up of the core of M23, showing some of its brightest member stars. Credit: Sharp/NOAO/AURA/NSF*

However, the most recent studies show that we have to determine radial velocities before we can really associate red giants as being cluster members. J.C. Mermilliod of Laboratoire d’Astrophysique de l’Ecole wrote in his 2008 study, “Red giants in open clusters“:

“The present material, combined with recent absolute proper motions, will permit various investigation of the galactic distribution and space motions of a large sample of open clusters. However, the distance estimates still remain the weakest part of the necessary data. This paper is the last one in this series devoted to the study of red giants in open clusters based on radial velocities obtained with the CORAVEL instruments.”

History of Observation:

This neat and tidy galactic star cluster was one of the original discoveries of Charles Messier. As he recorded of the cluster when first viewing it, which occurred on June 20th, 1764:

“In the night of June 20 to 21, 1764, I determined the position of a cluster of small stars which is situated between the northern extremity of the bow of Sagittarius and the right foot of Ophiuchus, very close to the star of sixth magnitude, the sixty-fifth of the latter constellation [Oph], after the catalog of Flamsteed: These stars are very close to each other; there is none which one can see easily with an ordinary refractor of 3 feet and a half, and which was taken for these small stars. The diameter of all is about 15 minutes of arc. I have determined its position by comparing the middle with the star Mu Sagittarii: I have found its right ascension of 265d 42′ 50″, and its declination of 18d 45′ 55″, south.”

The M23 open star cluster, as it appears in the night sky, flanked by M8 (Lagoon), M16 (Eagle), M17 (Omega), M20 (Trifid) and other deep sky objects. Credit & Copyright: Fernando Cabrerizo/NASA — The M23 open star cluster, as it appears in the night sky (a patch of red), flanked by M8 (Lagoon), M16 (Eagle), M17 (Omega), M20 (Trifid) and other deep sky objects. Credit & Copyright: Fernando Cabrerizo/NASA

While William Herschel did not publish his observations of Messier’s objects, he was still an avid observer. So of course, he had to look at this cluster, and wrote the following observations in his personal notes:

“A cluster of beautiful scattered, large stars, nearly of equal magnitudes (visible in my finder), it extends much farther than the field of the telescope will take in, and in the finder seems to be a nebula of a lengthened form extending to about half a degree.”

In July of 1835, Admiral Smyth would make an observation of Messier 23 and once again add his colorful remarks to the timeline:

“A loose cluster in the space between Ophiuchus’s left leg and the bow of Sagittarius. This is an elegant sprinkling of telescopic stars over the whole field, under a moderate magnifying power; the most clustering portion is oblique, in the direction sp to nf [south preceding to north following, SW to NE], with a 7th-magnitude star in the latter portion. The place registered it that of a neat pair, of the 9th and 10th magnitudes, of a lilac hue, and about 12″ apart. This object was discovered by Messier 1764, and it precedes a rich out-cropping of the Milky Way. The place is gained by differentiating the cluster with Mu Sagittarii, from which it bears north-west, distant about 5 deg, the spot being directed to by a line from Sigma on the shoulder, through Mu at the tip of the bow.”

Remember when observing Messier 23 that it won’t slap you in the face like many objects. Basically, it looks like a stellar scattering of freckles across the face of the sky when fully-resolved. It’s actually one of those objects that’s better to view with binoculars and low power telescopes.

Locating Messier 23:

M23 can be easily found with binoculars about a finger’s width north and two finger widths west of Mu Sagittarii. Or, simply draw a mental line between the top star in the teapot lid (Lambda) and Xi Serpentis. You’ll find a slight compression in the star field about halfway between these two stars that shows up as an open cluster with binoculars.

Using a finderscope, the object will appear nicely as a hazy spot. And for those using telescopes of any size, you’ll need to use fairly low magnification to help set this cluster apart from the surrounding star field, and it will resolve well to almost all instruments.

And here are the quick facts on this object to help you get started:

Object Name: Messier 23
Alternative Designations: M23, NGC 6494
Object Type: Open Star Cluster
Constellation: Sagittarius
Right Ascension: 17 : 56.8 (h:m)
Declination: -19 : 01 (deg:m)
Distance: 2.15 (kly)
Visual Brightness: 6.9 (mag)
Apparent Dimension: 27.0 (arc min)

We have written many interesting articles about Messier Objects here at Universe Today. Here’s Tammy Plotner’s Introduction to the Messier Objects, , M1 – The Crab Nebula, M8 – The Lagoon Nebula, and David Dickison’s articles on the 2013 and 2014 Messier Marathons.

Be to sure to check out our complete Messier Catalog. And for more information, check out the SEDS Messier Database.

Sources:

September 12, 2016October 5, 2016 by Matt Williams

Blue Origin Goes Big With New Glenn Rocket

Size comparison between the New Glenn and all other rockets currently in operations (with the Saturn V for comparison). Credit: Blue Origin

Space exploration is becoming a lucrative domain for private aerospace companies (aka. the NewSpace industry). With opportunities for launch and resupply services growing, costs dwindling, and the cancellation of the Space Shuttle Program, private companies have been stepping up in recent years to provide their own launch vehicles and services to fill the gap.

Take Jeff Bezos, for example. Back in 2000, the founder of Amazon.com created Blue Origin to fulfill his lifelong dream of colonizing space. For years, Bezos and the company he founded have been working to produce their own fleet of reusable rockets. And as of the morning of Monday, Sept. 12th, he unveiled their newest and heaviest rocket – the New Glenn.

Much like SpaceX, Blue Origin has been committed to the creation of reusable rocket technology. This was made clear with the development of the New Shepard suborbital rocket, which was unveiled in 2006. Named in honor of the first American astronaut to go into space (Alan Shepard), this rocket made its first flight in April of 2015 and has had an impressive record, nailing four out of five soft landings in the space of just over a year.

New Shepard comes in for a landing with drag brakes and landing gear deployed. Image: Blue Origin. — *New Shepard comes in for a landing with drag brakes and landing gear deployed. Credit: Blue Origin.*

With the New Glenn – named in honor of astronaut John Glenn, the first American astronaut to orbit the Earth – the company now intends to take the next step, offering launch services beyond Low-Earth Orbit (LEO) and for crewed missions. As Bezos said during the press conference:

“New Glenn is designed to launch commercial satellites and to fly humans into space. The three-stage variant-with its high specific impulse hydrogen upper stage—is capable of flying demanding beyond-LEO missions.”

According to Bezos, Blue Origin will have both a two-stage and three-stage variant of the rocket. Whereas the two-stage will provide heavier lift capacity to LEO, the three-stage will be able to reach further, and will the company’s go-to when sending crewed missions into space. Work on the rocket began back in 2012, and the company hopes to make their first launch prior to 2020.

As Bezos said during the unveiling, this rocket carries on in the same tradition that inspired the creation of the New Shepard:

“Building, flying, landing, and re-flying New Shepard has taught us so much about how to design for practical, operable reusability. And New Glenn incorporates all of those learnings. Named in honor of John Glenn, the first American to orbit Earth, New Glenn is 23 feet in diameter and lifts off with 3.85 million pounds of thrust from seven BE-4 engines. Burning liquefied natural gas and liquid oxygen, these are the same BE-4 engines that will power United Launch Alliance’s new Vulcan rocket.”

A United Launch Alliance (ULA) Delta IV rocket carrying the WGS-7 mission for the U.S. Air Force launches from Cape Canaveral Air Force Station, Fl, on July 23, 2015. Credit: Ken Kremer/kenkremer.com — *A United Launch Alliance (ULA) Delta IV rocket launching from Cape Canaveral Air Force Station, Fl, on July 23rd, 2015. Credit: Ken Kremer/kenkremer.com*

The rocket will have a sea-level thrust of 1.746 million kg (3.85 million lbs), placing it ahead of the Delta IV Heavy – which has a sea-level thrust of about 900,000 kg (2 million lbs) – but behind the 2.268 million kg (5 million lbs) of the Falcon Heavy. Both variants will be powered by BE-4 engines, which are also manufactured by Blue Origin. The third-stage also employs a single vacuum-optimized BE-3 engine that burns liquid hydrogen and liquid oxygen.

However, the most interesting facet of the New Glenn is the fact that it will be reusable, with its first stage providing braking thrust and deployable legs (similar to the Falcon 9). In creating a heavy lift rocket that employs a retrievable first-stage, Blue Origin has signaled its intent to give SpaceX a run for its money when it comes to the development of reusable rocket technology.

It is also likely to raise the company’s profile, which has so far been limited to conducting sub-orbital research for NASA and dabbling in the space-tourism industry. But once the New Glenn is up and running, it is likely to begin securing contracts to provide resupply services the ISS, as well as contracts with companies and research institutions to place satellites in orbit.

The Falcon Heavy, once operational, will be the most powerful rocket in the world. Credit: spacex.com

According to The Verge, Bezos also hinted that his company has another project in mind – called the New Armstrong. While no details have been given just yet, the name of this rocket is a clear allusion to the Moon Landing, and hints that the company may have designs on possible moon missions in the coming decades.

This is an exciting time for the NewSpace industry. In the coming months, SpaceX is expected to conduct the first launch of the Falcon Heavy, which will be the most powerful rocket built in the US since the retirement of the Apollo program’s Saturn V launcher. And if they keep to their current schedule, Blue Origin will be following this in a few years time with the launch of the largest rocket of the post-Apollo era.

Big rockets and big lift capacities can mean only thing: big things lie ahead of us!

Further Reading: ArsTechnica, The Verge, Blue Origin

September 12, 2016October 5, 2016 by Matt Williams

Stunning New Images Of Mars From The Curiosity Rover

Murray formation: rocks laid down by water and sculpted by wind — Finely layered rocks within the "Murray formation" layer of lower Mount Sharp on Mars. Credit: NASA

Since its deployment in 2012 to the surface of Mars, the Curiosity rover has sent back many breathtaking images of the Red Planet. In addition to snapping photos of the comet Siding Spring and Earth from the surface, not to mention some wonderful panoramic selfies, the rover has also taken countless images that show the geology and surface features of Mars’ in stunning detail.

And with the latest photos to be released by NASA, the Curiosity rover has provided us with a wonderful look at the “Murray Buttes” region, which is in the lower part of Mount Sharp. These images were taken by the Curiosity Mast Camera (Mastcam) on Sept. 8th, and provide some lovely insight into the geological history of the region.

Using these images, the Curiosity team hopes to assemble another impressive color mosaic that will give a detailed look at the region’s rocky, desert-like landscape. As you can see from the images provided, the region is characterized by mesas and buttes, which are the eroded remnants of ancient sandstone. Much like other spots around Mount Sharp, the area is of particular interest to the Curiosity team.

Sloping buttes and layered outcrops within the "Murray formation" layer of lower Mount Sharp. Credit: NASA — *Sloping buttes and layered outcrops within the “Murray formation” layer of lower Mount Sharp. Credit: NASA*

For years, scientists have understood that the rock layers that form the base of Mount Sharp accumulated as a result of sediment being deposited within the ancient lake bed billions of years ago. In this respect, the geological formations are similar to those found in the desert regions of the southwestern United States.

Ashwin Vasavada, the Curiosity Project Scientist of NASA’s Jet Propulsion Laboratory, told Universe Today via email:

” The Murray Buttes region of Mars is reminiscent of parts of the American southwest because of its butte and mesa landscape. In both areas, thick layers of sediment were deposited by wind and water, eventually resulting in a “layer cake” of bedrock that then began to erode away as conditions changed. In both places, more resistant sandstone layers cap the mesas and buttes because they protect the more easily eroded, fine-grained rock underneath.

“Like at Monument Valley near the Utah-Arizona border, at Murray Buttes there are just small remnants of these layers that once covered the surface more completely. There were wind-driven sand dunes at both places, too, that now appear as cross-bedded sandstone layers. There are of course many differences between Mars and the American Southwest. For example, there were large inland seas in the Southwest, while at Gale crater there were lakes.”

These sediment layers are believed to have been laid down over the course of 2 billion years, and may have completely filled the crater at one time. Since it is widely believed that lakes and streams existed in the Gale Crater 3.3 – 3.8 billion years ago, some of the lower sediment layers may have originally been deposited on a lake bed.

A hillside outcrop with finely layered rocks within the "Murray formation" layer of lower Mount Sharp. Credit: NASA — *A hillside outcrop with finely layered rocks within the “Murray formation” layer of lower Mount Sharp. Credit: NASA*

For this reason, the Curiosity team also took drill samples from the Murray Buttes area for analysis. This began on Sept. 9th, after the rover was finished taking pictures of the area. As Vasavada explained:

“The Curiosity team is drilling regularly as the rover ascends Mount Sharp. We are drilling into the fine-grained rock that was deposited within lakes in order to see how the lake chemistry, and therefore the environment, changed over time. Curiosity drilled into the coarser sandstone that forms the upper layers of the buttes when the rover crossed the Naukluft Plateau earlier in 2016.”

After the drilling is completed, Curiosity will continue farther south and higher up Mount Sharp, leaving behind these spectacular formations. These pictures represent Curiosity‘s last stop in the Murray Buttes, where the rover has been spending the past month.

And as of this past September 11th, 2016, Curiosity has been on the planet Mars for a total of 4 years and 36 days (or 1497 Earth days; 1458 sols) since it landed on August 6th, 2012.

One has to wonder how the pareidolia folks are going to interpret these ones. After “seeing” a rat, a lizard, a doughnut, a coffin, and so forth, what’s left? Might I suggest that the top image kind of looks like a statue-column?

Further Reading: NASA – Solar System Exploration

September 12, 2016September 17, 2016 by Bob King

The Big Dipper in the Year 92,000

Stellar motions distort the future sky. Map: Bob King, Source: Stellarium

If we could transport Ptolemy, a famous astronomer who lived circa 90 – 168 A.D. in Alexandria, Egypt, he would have noticed the shift in position of Arcturus, Sirius and Aldebaran since his time. Everything else would appear virtually unchanged. — If we could transport **Ptolemy**, a famous astronomer who lived circa 90 – 168 A.D. in Alexandria, Egypt, he would have noticed the shift in position of Arcturus, Sirius and Aldebaran since his time. Everything else would appear virtually unchanged.

You go out and look at the stars year after year and never see any of them get up and walk away from their constellations. Take a time machine back to the days of Plato and Socrates and only careful viewing would reveal that just three of the sky’s naked eye stars had budged: Arcturus, Sirius and Aldebaran. And then only a little. Their motion was discovered by Edmund Halley in 1718 when he compared the stars’ positions then to their positions noted by the ancient Greek astronomers. In all three cases, the stars had moved “above a half a degree more Southerly at this time than the Antients reckoned them.”

NGC 4414 is a spiral galaxy that resembles our own Milky Way. I've drawn in the orbits of several stars. Both disk and halo stars orbit about the center but halo stars describe long elliptical orbits. When they plunge through the disk, if they happen to be relatively nearby as is Arcturus, they'll appear to move relatively quickly across the sky. Credit: NASA/ESA — NGC 4414 is a spiral galaxy that resembles our own Milky Way. I’ve drawn in the orbits of several stars. Both disk and halo stars orbit about the center, but halo stars describe long elliptical orbits that take them well beyond the disk. When a star plunges through the disk, if it happens to be relatively nearby as in the case of Arcturus, the star will appear to move relatively quickly across the sky. Both distance and the type of orbit a star has can affect how fast it moves from our perspective. Credit: NASA/ESA with orbits by the author

Stars are incredibly far away. I could throw light years around like I often do here, but the fact is, you can get a real feel for their distance by noting that during your lifetime, none will appear to move individually. The gems of the night and our sun alike revolve around the center of the galaxy. At our solar system’s distance from the center — 26,000 light years or about halfway from center to edge — it takes the sun about 225 million years to make one revolution around the Milky Way.

That’s a LONG time. The other stars we see on a September night take a similar length of time to orbit. Now divide the average lifetime of some 85 years into that number, and you’ll discover that an average star moves something like .00000038% of its orbit around the galactic center every generation. Phew, that ain’t much! No wonder most stars don’t budge in our lifetime.

This graphic, compiled using SkyMap software created by Chris Marriott, shows the motion of Arcturus over — This graphic, made using SkyMap software created by Chris Marriott, shows the motion of Arcturus over a span of 8,000 years.

Sirius, Aldebaran and Arcturus and several other telescopic stars are close enough that their motion across the sky becomes apparent within the span of recorded history. More powerful telescopes, which expand the scale of the sky, can see a great many stars amble within a human lifetime. Sadly, our eyes alone only work at low power!

Precession of Earth's axis maintains it usual 23.5 degree tilt, but this causes the axis to describe a circle in the sky like a wobbling top. Credit: Wikimedia Commons — Precession of Earth’s axis maintains its usual 23.5 degree tilt, but this causes the axis to describe a circle in the sky like a wobbling top. The photo is an animation that repeats 10 seconds, so hang in there. Credit: Wikimedia Commons

But we needn’t invest billions in building a time machine to zing to the future or past to see how the constellation outlines become distorted by the individual motions of the stars that compose them. We already have one! Just fire up a free sky charting software program like Stellarium and advance the clock. Like most such programs, it defaults to the present, but let’s look ahead. Far ahead.

If we advance 90,000 years into the future, many of the constellations would be unrecognizable. Not only that, but more locally, the precession of Earth’s axis causes the polestar to shift. In 2016, Polaris in the Little Dipper stands at the northernmost point in the sky, but in 90,000 years the brilliant star Vega will occupy the spot. Tugs from the sun and moon on Earth’s equatorial bulge cause its axis to gyrate in a circle over a period of about 26,000 years. Wherever the axis points defines the polestar.

I advanced Stellarium far enough into the future to see how radically the Big Dipper changes shape over time. Notice too that Vega will be the polestar in that distant era. Map: Bob King, Source: Stellarium

Take a look at the Big Dipper. Wow! It’s totally bent out of shape yet still recognizable. The Pointer Stars no longer quite point to Polaris, but with some fudging we might make it work. Vega stands near the pole, and being much closer to us than the rest of Lyra’s stars, has moved considerably farther north, stretching the outline of the constellation as if taffy.

Now let's head backwards in time 92,000 years to 90,000 B.C. The Dipper then was fairly unrecognizable, with both Vega and Arcturus near the pole. Map: Bob King , Source: Stellarium — Now let’s head backwards in time 92,000 years to 90,000 B.C. The Dipper then was fairly unrecognizable, with both Vega and Arcturus near the pole. Map: Bob King , Source: Stellarium

Time goes on. We look up at the night sky in the present moment, but so much came before us and much will come after. Constellations were unrecognizable in the past and will be again in the future. In a fascinating discussion with Michael Kauper of the Minnesota Astronomical Society at a recent star party, he described the amount of space in and between galaxies as so enormous that “we’re almost not here” in comparison. I would add that time is so vast we’re likewise almost not present. Make the most of the moment.