Watch Stars Orbit The Milky Way’s Supermassive Black Hole

Stars circle 'round the Milky Way central supermassive black hole. Credit: ESO

The Milky Way’s supermassive black hole, called Sagittarius A* (or Sgr A*), is arrowed in the image made of the innermost galactic center in X-ray light by NASA’s **Chandra Observatory**. To the left or east of Sgr A* is Sgr A East, a large cloud that may be the remnant of a supernova. Centered on Sgr A* is a spiral shaped group of gas streamers that might be falling onto the hole. Credit: NASA/CXC/MIT/Frederick K. Baganoff et al.

When your ordinary citizen learns there’s a supermassive black hole with a mass of 4 million suns sucking on its teeth in the center of the Milky Way galaxy, they might kindly ask exactly how astronomers know this. A perfectly legitimate question. You can tell them that the laws of physics guarantee their existence or that people have been thinking about black holes since 1783. That year, English clergyman John Michell proposed the idea of “dark stars” so massive and gravitationally powerful they could imprison their own light.

This time-lapse movie in infrared light shows how stars in the central light-year of the Milky Way have moved over a period of 14 years. The yellow mark at the image center represents the location of Sgr A*, site of an unseen supermassive black hole.
Credit: A. Eckart (U. Koeln) & R. Genzel (MPE-Garching), SHARP I, NTT, La Silla Obs., ESO

Michell wasn’t making wild assumptions but taking the idea of gravity to a logical conclusion. Of course, he had no way to prove his assertion. But we do. Astronomers now routinely find bot stellar mass black holes — remnants of the collapse of gas-guzzling supergiant stars — and the supermassive variety in the cores of galaxies that result from multiple black hole mergers over grand intervals of time.

Some of the galactic variety contain hundreds of thousands to billions of solar masses, all of it so to speak “flushed down the toilet” and unavailable to fashion new planets and stars. Famed physicist Stephen Hawking has shown that black holes evaporate over time, returning their energy to the knowable universe from whence they came, though no evidence of the process has yet been found.

On September 14, 2013, astronomers caught the largest X-ray flare ever detected from Sgr A*, the supermassive black hole at the center of the Milky Way, using NASA’s Chandra X-ray Observatory. This event was 400 times brighter than the usual X-ray output from the source and was possibly caused when Sgr A*’s strong gravity tore apart an asteroid in its neighborhood, heating the debris to X-ray-emitting temperatures before slurping down the remains.The inset shows the giant flare. Credit: NASA

So how do we really know a massive, dark object broods at the center of our sparkling Milky Way? Astronomers use radio, X-ray and infrared telescopes to peer into its starry heart and see gas clouds and stars whirling about the center at high rates of speed. Based on those speeds they can calculate the mass of what’s doing the pulling.

The Hubble Space Telescope took this photo of the 5000-light-year-long jet of radiation ejected from the active galaxy M87’s supermassive black hole, which is aboutt 1,000 times more massive than the Milky Way’s black hole. Although black holes are dark, matter whirling into their maws at high speed is heated to high temperature, creating a bright disk of material and jets of radiation. Credit: NASA/The Hubble Heritage Team (STScI/AURA)

In the case of the galaxy M87 located 53.5 million light years away in the Virgo Cluster, those speeds tell us that something with a mass of 3.6 billion suns is concentrated in a space smaller than our Solar System. Oh, and it emits no light! Nothing fits the evidence better than a black hole because nothing that massive can exist in so small a space without collapsing in upon itself to form a black hole. It’s just physics, something that Mr. Scott on Star Trek regularly reminded a panicky Captain Kirk.

So it is with the Milky Way, only our black hole amounts to a piddling 4 million-solar-mass light thief confined within a spherical volume of space some 27 million miles in diameter or just shy of Mercury’s perihelion distance from the Sun. This monster hole resides at the location of Sagittarius A* (pronounced A- star), a bright, compact radio source at galactic center about 26,000 light years away.

Video showing a 14-year-long time lapse of stars orbiting Sgr A*

The time-lapse movie, compiled over 14 years, shows the orbits of several dozen stars within the light year of space centered on Sgr A*. We can clearly see the star moving under the influence of a massive unseen body — the putative supermassive black hole. No observations of Sgr A* in visible light are possible because of multiple veils of interstellar dust that lie across our line of sight. They quench its light to the tune of 25 magnitudes.

Merging black holes (the process look oddly biological!). Credit: SXS

How do these things grow so big in the first place? There are a couple of ideas, but astronomers don’t honestly know for sure. Massive gas clouds around early in the galaxy’s history could have collapsed to form multiple supergiants that evolved into black holes which later then coalesced into one big hole. Or collisions among stars in massive, compact star clusters could have built up stellar giants that evolved into black holes. Later, the clusters sank to the center of the galaxy and merged into a single supermassive black hole.

Whichever you chose, merging of smaller holes may explain its origin.

On a clear spring morning before dawn, you can step out to face the constellation Sagittarius low in the southern sky. When you do, you’re also facing in the direction of our galaxy’s supermassive black hole. Although you cannot see it, does it not still exert a certain tug on your imagination?

March 24, 2017April 4, 2017 by Matt Williams

Process Behind Martian Streaks Continues To Puzzle

These dark streaks, called recurring slope lineae, are on a sloped wall on a crater on Mars. A new study says they may have been formed by boiling water. Image: NASA/JPL-Caltech/Univ. of Arizona — These dark streaks, called recurring slope lineae (RSL), are on the sloped wall of a crater on Mars. A new study says they may have been formed by boiling water. Credit: NASA/JPL-Caltech/Univ. of Arizona

It’s a well-documented fact that roughly 4 billion years ago, Mars had liquid water flowing on its surface. However, there have also been recent findings that suggest that Mars might periodically have liquid water on its surface today. One of the strongest bits of evidence comes in the form of Recurring Slope Lineae, which are ventured to be seasonal flows of salty water which occur during Mars’ warmest months.

However, a new study produced by an international team of scientists has casts doubt on this theory and offered another possible explanation. Using numerical simulations, they show how a “dry” process – where rarefied gas is pumped up through the soil (due to temperature variations) – could lead to the formation of the dark streaks that have been observed on Martian slopes.

Their study, titled “Formation of recurring slope lineae on Mars by rarefied gas-triggered granular flows“, appeared recently in the journal Nature Geoscience. In it, the research team – which hails from the Géosciences Paris Sud (GEOPS) laboratory in Orsay, France, and the Slovak Academy of Sciences in Bratislava- explain how the current theories about what creates RSLs fall short.

*Reprojected view of warm-season flows in Newton Crater. Credit: NASA/JPL-Caltech/Univ. of Arizona*

As Frédéric Schmidt, a professor from GEOPS and the lead author of the study told Universe Today via email, the current theory about RSLs is based on the morphology, composition and seasonality of lineae which in the past, seemed to suggest that liquid salt water played a role in their formation:

“They attributed the appearance to liquid water mainly because of seasonality and salt detection. The activity occurs at the maximum temperature season only, in the most favorable condition for water to be liquid. The salt permits to decrease the freezing temperature of liquid water.”

This theory has met with its share of excitement, considering that the presence of water on the Martian surface would mean that the chances of finding present-day life there would be significantly greater. Unfortunately, recent studies have cast doubt on this by showing how there is insufficient water on Mars to account for the lineae that have been observed on various slopes.

“[T]here is not enough atmospheric water to fill all the dark flows and internal subsurface sources are very unlikely (Chojnacki et al., 2016),” said Dr. Schmidt. “Also, because there is no signature in the thermal range as one may have in the case of abundant liquid water. From the data, the maximum allowed water is too little (Edwards et al., 2016).”

*Evolution of RSL at Garni Crater, Valles Marineris, Mars. Credit: MRO, HiRISE, NASA/JPL/University of Arizona*

However, Mars does have sufficient air pressure to allow for another process known as thermal creep. Also known as thermal transpiration, this process involves gas molecules drifting from the cold end of a narrow channel to the warm end. This occurs as a result of the walls of the channel experiencing temperature changes, which triggers a gas flow.

According to their study, sections of the Martian surface could be heated by solar radiation while others remained cooler because they were covered by a source of shade. When this happens, rarefied gas beneath the surface (i.e. gas with lower pressure than the atmosphere) could be pumped up through the Martian soil. Once it reached the surface, this gas would disturb patches of small particles, triggering tiny avalanches along Martian slopes.

To test this “dry” process of RSL formation, the team ran numerical simulations that took into account various locations on Mars and seasonal changes. “We tested our theory by modeling it and estimating its efficiency for different facet orientation and different seasons,” said Dr. Schmidt. “We find that the observed activity is coherent with our prediction. Also we simulated it in the lab in order validate the principle.

Basically, they found that in rough and boulder-strewn terrain on Mars (where shadows are cast that can cause temperature differences in small sections of soil) this process could result in the formation of dark streaks along slopes. Not only were their results consistent with observered RSLs in some areas, but they also explained how they could form without the need for liquid water or CO² frost (dry ice) activity.

Simulation of the 100 meter-long recurring slope lineae detected on the Hale crater, produced by the High Resolution Imaging Science Experiment (University of Arizona). Credits: NASA/JPL/University of Arizona

This may sound like bad news, and it certainly is if you’re planning on establishing a settlement on Mars anytime soon (Elon Musk and Bas Lansdorp might want to take heed!). And as Dr. Schmidt explained, it doesn’t bode well for those who are looking to confirm that there could be present-day life on Mars either:

“Since RSL are the main features to argue about the presence of liquid water at present time on Mars, it was also the argument for possible habitability and life on Mars. If the new theory is correct, the present Mars is not as habitable as we previously thought. Liquid water was most probably present billions of years ago, but not today. These findings paint the portrait of an inhospitable world for human exploration.”

So it seems that the prospect of water-procurement on Mars might be trickier than we thought. Perhaps future missions to the surface that rely on in-situ resource utilization (ISRU) will either have to drill for water, or harvest it directly from the ice caps. And as for full-blown colonization plans… well, let’s hope they don’t mind drilling wells or chopping ice either!

Further Reading: Nature Geoscience

March 24, 2017April 4, 2017 by Evan Gough

German ‘Largest Artificial Sun’ To Generate Climate Friendly Fuel

Technicians at the DLR's Institute for Solar Research inspecting lamps in the Synlight. Image: DLR/Markus Hauschild.

Hydrogen is the most abundant element in the Universe. But here on Earth, it’s rather rare. That’s unfortunate, because in our warming world, its status as an emissions-free fuel makes it a coveted chemical. If German researchers are successful, their Synlight project will help make renewable hydrogen fuel a reality.

Dubbed the “artificial Sun”, the Synlight uses concentrated light to power Thermochemical Water Splitting (TWS.) Every school child knows you can produce hydrogen by electrolysis—running an electric current through water. But that takes an enormous amount of electricity. TWS might be a better way of getting hydrogen out of water, but it takes an enormous amount of energy too, and that’s what the German research is about.

When combusted with pure oxygen—inside a fuel cell for example—hydrogen’s only waste product is water. No greenhouse gases or particulates are produced. But if we want to use it to power our cars, buses, trucks, and even airplanes, we need enormous amounts of it. And we need to produce it cost-effectively.

“Renewable energies will be the mainstay of global power supply in the future.” – Karsten Lemmer DLR Executive Board Member

The idea is to use the heat generated by Concentrated Solar Power (CSP) to extract hydrogen from water, thereby eliminating the need for electricity. CSP systems use mirrors or lenses to concentrate a large area of sunlight into a small area. The heat from that action can be used to power TWS. The Synlight project in Germany is demonstrating the viability of TWS by mimicking the effect of concentrated sunlight. In doing so, researchers there are building what’s being called the world’s largest artificial Sun.

Each of Synlight’s 149 zenon short-arc lamps can be controlled individually. Image: DLR/Synlight/Markus Hauschild

German researchers at the German Aerospace Center (DLR) at Julich near Cologne built the Synlight, a system of 149, high power lamps of the type used in film projections. When all these lamps are turned on, Synlight produces light that is about 10,000 times more intense than natural sunlight on Earth. When all the lamps are aimed at a single spot, Synlight generates temperatures up to 3000 Celsius. The challenge now is to develop materials and processes that can operate in such an extreme temperature.

The 15m tall Synlight experiment is housed in this building in Julich. The building contains 3 separate radiation chambers for different experiments. Image: DLR CC By 3.0

The Synlight system itself uses an enormous amount of electrical power to operate. But that’s often the case with experimental facilities. The Synlight project will mimic the effect of intense, continuous solar energy, something that is not readily available in Germany. By building a test facility powered by electricity, researchers will be able to reliably perform experiments without being delayed or affected by cloudy weather.

“Fuels, propellants and combustibles acquired using solar power offer immense potential for long-term storage and the production of chemical raw materials, and the reduction of carbon dioxide emissions. Synlight will enhance our research in this field.” – Karsten Lemmer, DLR Executive Board Member

As Johannes Remmel, the North Rhine-Westphalia Minister for Climate Protection, said, “”We need to expand existing technology in practical ways in order to achieve renewable energy targets, but the energy transition will falter without investments in innovative research, in state-of-the-art technologies and in global lighthouse projects like Synlight.”

The DLR is involved in the PS10 solar power tower in Spain. The PS10 is the world’s fist commercial concentrating solar power tower. Image: By afloresm – SOLUCAR PS10, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=2821733

This is not the German Aerospace Center’s first foray in concentrated solar power. They’re involved in a number of projects to advance concentrated solar power and thermal water splitting. The DLR is a partner in the Hydrosol II pilot in Spain. It’s a reactor for solar thermochemical hydrogen production that has been in operation since 2008. They’re also involved in the first commercially operated solar tower plant, an 11 megawatt system in Spain called the PS10 solar power tower.

March 23, 2017April 4, 2017 by Matt Williams

Curiosity Captures Gravity Wave Shaped Clouds On Mars

Mars, as photographed with the Mars Global Surveyor, is identified with the Roman god of war. Credit: NASA

This week, from March 20th to 24th, the 48th Lunar and Planetary Science Conference will be taking place in The Woodlands, Texas. Every year, this conference brings together international specialists in the fields of geology, geochemistry, geophysics, and astronomy to present the latest findings in planetary science. One of the highlights of the conference so far has been a presentation about Mars’ weather patterns.

As a team of researchers from the Center for Research in Earth and Space Sciences (CRESS) at York University, demonstrated, Curiosity obtained of some rather interesting images of Mars’ weather patterns over the past few years. These included changes in cloud cover, as well as the first ground-based view of Martian clouds shaped by gravity waves.

When it comes to cloud formations, gravity waves are the result of gravity trying to restore them to their natural equilibrium. And while common on Earth, such formation were not thought to be possible around Mars’ equatorial band, where the gravity waves were seen. All of this was made possible thanks to Curiosity’s advantageous position inside the Gale Crater.

Cirrus clouds in the Martian atmosphere may have helped keep Mars warm enough for liquid water to sculpt the Martian surface. Image: Mars Exploration Rover Mission, Cornell, JPL, NASA — *Panoramic image showing cirrus clouds in the Martian atmosphere, taken by the Opportunity rover in 2006. Credit: NASA/JPL/Cornell/M. Howard, T. Öner, D, Bouic & M. Di Lorenzo*

Located near Mars’ equator, Curiosity has managed to consistently record what is known as the Aphelion Cloud Belt (ACB). As the name would suggest, this annually-recurring phenomena appears during the aphelion season on Mars (when it is farthest from the Sun) between the latitudes of 10°S and 30°N. During aphelion, the point farthest from the Sun, the planet is dominated by two cloud systems.

These include the aforementioned ACB, and the polar phenomena known as Polar Hood Clouds (PHCs). Whereas PHCs are characterized by clouds of carbon dioxide, clouds that form around Mars’ equatorial band are made up water-ice. These cloud systems them dissipate as Mars gets closer to the Sun (perihelion), where increases in temperature lead to the creation of dust storms that limit cloud formation.

During the nearly five years that Curiosity has been operational, the rover has recorded over 500 movies of the equatorial Martian sky. These movies have taken the form of both Zenith Movies (ZMs) – which involve the camera being pointed vertically – and Supra-Horizon Movies (SHM), which were aimed at a lower angle of elevation to keep the horizon in frame.

Using Curiosity’s navigation camera, Jacob Kloos and Dr. John Moores – two researchers from CRESS – made eight recordings of the ACB over the course of two Martian years – specifically between Mars Years 31 and Mars Years 33 (ca. 2012 to 2016). By comparing ZM and SHM movies, they were able to discern changes in the clouds that were both diurnal (daily) and annual in nature.

What they found was that between 2015 and 2016, Mars’ ACB underwent changes in opacity (aka. changes in density) during its diurnal cycle. After periods of enhanced early morning activity, the clouds would reach a minimum by late morning. This is followed by a second, lower peak in the late afternoon, which indicated that Mars’ early morning hours are the most favorable time for the formation of thicker clouds.

Hubble images show cloud formations (left) and the effects of a global dust storm on Mars. Credit: NASA/James Bell (Cornell Univ.), Michael Wolff (Space Science Inst.), and Hubble Heritage Team (STScI/AURA)

As for inter-annual variability, they found that between 2012 and 2016, when Mars moved away from aphelion, there was a corresponding 38% increase in the number of higher-opacity clouds. However, believing these results to be the result of a statistical bias caused by an uneven distribution of videos, they concluded that the difference in opacity was more along the lines of about 5%.

These variations were all of this is consistent with tidal temperature variations, where cooler daytime or seasonal temperatures result in greater levels of condensation in the air. The trend of increasing clouds throughout the day was unexpected, however, as higher temperatures should lead to a decrease in saturation. However, as they explained during their presentation, this too could be attributed to daily changes:

“One explanation for the afternoon enhancement put forth by Tamppari et. al. is that as atmospheric temperatures increase the throughout the day, enhanced convection lifts water vapor to the saturation altitude, therefore increasing the likelihood of cloud formation. In addition to water vapor, dust could also be lifted, which act as condensation nuclei, allowing for more efficient cloud formation.”

However, what was most interesting was the fact that during one of day of observation – Sol 1302, or April 5th, 2016 – the team managed to observe something surprising. When looking at the horizon during an SHM, the NavCam caught sight of parallel rows of clouds which all pointed in the same direction. While such ripples are known to happen in the polar regions (where PHCs are concerned), spotting them over the equator was unexpected.

*Sunset photographed from Gale Crater by the Mars Curiosity rover on April 15, 2015 taken using the left eye of the rover’s Mastcam. Credit: NASA/JPL-Caltec*

But as Moore explained in an interview with Science Magazine, seeing an Earth-like phenomenon on Mars is consistent with what we’ve seen so far from Mars. “The Martian environment is the exotic wrapped in the familiar,” he said. “The sunsets are blue, the dust devils enormous, the snowfall more like diamond dust, and the clouds are thinner than what we see on the Earth.”

At present, it is not clear which mechanism could be responsible for creating these ripples in the first place. On Earth, they are caused by disturbances below in the troposphere, solar radiation, or jet stream sheer. Knowing what could account for them on Mars will likely reveal some interesting things about its atmosphere’s dynamics. At the same time, further research is necessary before scientists can say definitely that gravity waves were observed here.

But in the meantime, these findings are fascinating, and are sure to help advance our knowledge of the Red Planet’s atmosphere and the water cycle on Mars. As ongoing research has shown, Mars still experiences flows of liquid salt water on its surface, and even experiences limited precipitation. And in telling us more about Mars’ present-day meteorology, it could also reveal things about the planet’s watery past.

To see the recordings of Martian clouds, click here, here and here.

Further Reading: USRA, Science Magazine

March 23, 2017April 4, 2017 by Evan Gough

New Study Wants To Rip T-Rex From Its Place On Dino Tree

A reconstruction of a T. Rex at the Field Museum of Natural History, Chicago. This is Sue, the world's largest and most complete dinosaur skeleton. Image: By Connie Ma Uploaded by FunkMonk, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=20207230

To kids, there are only two kinds of dinosaurs: meat-eaters and plant-eaters. But to paleontologists, those are just diet distinctions. Paleontologists divide dinos into two different groups based largely on pelvic structure: reptile-hipped saurischians, and bird-hipped ornithischians.

Those two categories are called ‘clades’, and they’re fundamental to the study of dinosaurs. But a new study is casting doubt on those two groups, as well as moving the infamous Tyrannosaurus Rex to a new spot on the dinosaur family tree.

The study, by Matthew G. Baron, David B. Norman & Paul M. Barrett, was published in the journal Nature. If the findings in this study are accepted by paleontologists, then it will upset our understanding of the family tree that was first established in Victorian times.

Pelvic Structure of a reptile-hipped saurischian. Image: By Fred the Oyster, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=35371104

Pelvic structure of a bird-hipped ornithischian. Image: By Fred the Oyster, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=35371104

The T. Rex is the most famous member of the reptile-hipped saurischians. Many other carnivorous theropods are saurischians too, like Giganotosaurus and Spinosaurus. Other famous dinosaurs, like Stegosaurus, are bird-hipped ornithischians. The distinction between the saurischians and the ornithischians has been workable for a long time. But there were always problems with the two clades of dinosaurs.

The Dinosaur Family Tree. Image: By Evolution_of_dinosaurs_by_Zureks.svg: Zureksderivative work: Woudloper (talk) – Evolution_of_dinosaurs_by_Zureks.svg, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6321464

Some of the earliest ornithischian dinosaurs in the Triassic period had some theropod qualities: they were bipedal and probably meat-eaters. This clouded the separation between ornithischians and saurischians. There are also the herrerasaurids, small dinosaurs not larger than 4 meters long. They were some of the earliest dinosaurs, carnivores that look like both sauropods and theropods, and even though they appear early in the fossil record, they are not considered ancestors to any other group of dinosaurs. They show a mixture of both primitive and derived traits.

Huge plant-eating sauropods like the Brontosaurus and the Diplodocus are included in the reptile-hipped saurischians with the meat-eating theropods, even though there are some key skeletal differences between the two groups.

Another problem centers around birds. Believe it or not, birds have theropods as ancestors, even though theropods are in the reptile-hipped clade, rather than the bird-hipped clade.

Are You Confused Yet?

If this all seems kind of confusing, let’s back up for a minute.

When we think of dinosaurs, we tend to think of full-scale rebuilt skeletons of the type on display in museums around the world. But for paleontologists, the reality is much different. Many dinosaur species are known only by a few bones or teeth. These samples are studied in great detail. Any groove in a bone or slightly different shape in a tooth is analyzed, and out of this a dinosaur family tree is constructed.

It’s hard work, and our fossil record is spotty at best. Some new dinosaur taxa are proposed based only on the discovery of isolated teeth in the fossil record. With all of this in mind, you can see that the dinosaur family tree is an ongoing work in progress.

The authors of the study say that many ornithischian dinosaurs were overlooked in the past, because paleontologists didn’t really know what to do with them. Many of the ornithischians had weird traits like extra chin bones and molar-like teeth in their cheeks. These ornithischian dinos were thought of as oddities, early offshoots from other species.

New Clades

The authors studied 457 traits in 74 taxa, looking at details like the shapes of tiny eye-socket bones and grooves on femurs. They found that Theropods, even though they have reptile-like hips, don’t belong in the saurischian clade. They’re suggesting that Theropods are a sister clade to the ornithischians. The revised grouping of Ornithischia and Theropoda has been named the Ornithoscelida. The authors are also proposing that the herrerasaurids did not branch off as early as previously thought, and should form a sister clade with the sauropods.

But this study does even more. It’s been long understood by paleontologists that dinosaurs appeared in the southern hemisphere first. That’s where the herrerasaurids were found, dating back to 240 million years ago. The authors remind us that there are very few Herrerasaurus skeletons and bones, and there are uncertainties in the age of the Triassic fossil beds where herrerasaurids are found. A nearly complete skeleton was found in Argentina, and less complete ones have been found in North America.

But this shuffling of the family tree moves the herrerasaurids further away from the base of the tree. Remember, the herrerasaurids look like both sauropods and theropods, and they show both derived and primitive traits. If it’s accepted that the herrerasaurids did not appear as early as thought, that might mean that dinos did not appear first in the southern hemisphere. The authors say that some enigmatic fossils found in the northern hemisphere should be re-examined in case they are earlier than the ones found in the south.

Enter the Saltopus

A fossil of a cat-like creature found in Scotland, called the Saltopus, is a part of the shake-up of the dinosaur family tree. It was considered a pre-cursor to dinosaurs, rather than a true dinosaur. As part of their analysis, the Saltopus has been re-positioned in the earliest part of the dinosaur lineage, as the first true dinosaur. This supports the idea that dinosaurs appeared first in the northern hemisphere rather than the south.

The Saltopus, a small cat-sized dinosaur found in Scotland. If it is the first dinosaur, that means dinosaurs originated in the northern hemisphere rather than the south. Image: By Nobu Tamura email:[email protected] http://spinops.blogspot.com/ http://paleoexhibit.blogspot.com/ – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=50251442

If this new family tree for dinosaurs is accepted, it will change our understanding of the way dinosaurs evolved. We’ve relied on similarity in hip shape to ascertain ancestry, but that may be a little simplistic.

Our understanding of dinosaurs changes frequently. Remember when dinosaurs were slow, dim-witted creatures with tiny brains and huge bodies? Now we think of dinosaurs as feathered and fast, using cunning and perhaps teamwork to hunt in packs. Remember when the prevailing wisdom was that some dinosaurs got so large and spiny that they were doomed to extinction? That was proven false as well.

If it does stick, this new family tree will be a huge change in paleontology, a field where knowledge is overturned on a regular basis, sometimes by little more than a few teeth.

March 22, 2017April 4, 2017 by Matt Williams

Curiosity’s Battered Wheels Show First Breaks

Image taken by the Mars Hand Lens Imager (MAHLI) of Curiosity's wheels on March 19, 2017. Credit: NASA

Since it landed on August 6th, 2012, the Curiosity rover has spent a total of 1644 Sols (or 1689 Earth days) on Mars. And as of March 2017, it has traveled almost 16 km (~10 mi) across the planet and climbed almost a fifth of a kilometer (0.124 mi) uphill. Spending that kind of time on another planet, and traveling that kind of distance, can certainly lead to its share of wear of tear on a vehicle.

That was the conclusion when the Curiosity science team conducted a routine check of the rover’s wheels on Sunday, March 19th, 2017. After examining images taken by the Mars Hand Lens Imager (MAHLI), they noticed two small breaks in the raised treads on the rover’s left middle wheel. These breaks appeared to have happened since late January, when the last routine check of the wheels took place.

To get around, the Curiosity rover relies on six solid aluminum wheels that are 40 cm (16 in) wide. The skin of the wheels is thinner than a US dime, but each contains 19 zigzag-shaped treads that are about 0.75 cm (three-quarters of an inch) thick. These “grousers”, as they are called, bear most of the rover’s weight and provide most of the wheel’s traction.

*Close-up image of the broken grousers on Curiosity’s left-middle wheel. Credit: NASA/JPL-Caltech/MSSS*

Ever since the rover was forced to cross a stretch of terrain that was studded with sharp rocks in 2013, the Curiosity team has made regular checks on the rover’s wheels using the MAHLI camera. At the time, the rover was moving from the Bradbury Landing site (where it landed in 2012) to the base of Mount Sharp, and traversing this terrain caused holes and dents in the wheels to grow significantly.

However, members of Curiosity’s science team emphasized that this is nothing to be worried about, as it will not affect the rover’s performance or lifespan. As Jim Erickson, the Curiosity Project Manager at NASA’s Jet Propulsion Laboratory, said in a recent NASA press statement:

“All six wheels have more than enough working lifespan remaining to get the vehicle to all destinations planned for the mission. While not unexpected, this damage is the first sign that the left middle wheel is nearing a wheel-wear milestone.”

In addition to regular monitoring, a wheel-longevity testing program was started on Earth in 2013 using identical aluminum wheels. These tests showed that once a wheel got to the point where three of its grousers were broken, it had passed about 60% of its lifespan. However, Curiosity has already driven more than 60% of the total distance needed for it to make it to all of its scientific destinations.

*Graphic depicting aspects of the driving distance, elevation, geological units and time intervals of NASA’s Curiosity Mars rover mission, as of late 2016. Credit: NASA/JPL-Caltech*

Curiosity’s Project Scientist – Ashwin Vasavada, also at JPL – was similarly stoic in his appraisal of this latest wheel check:

“This is an expected part of the life cycle of the wheels and at this point does not change our current science plans or diminish our chances of studying key transitions in mineralogy higher on Mount Sharp.”

At present, Curiosity is examining sand dunes in the geographical region known as the Murray Buttes formation, which is located on the slope of Mount Sharp. Once finished, it will proceed up higher to a feature known as “Vera Rubin Ridge”, inspecting a layer that is rich in the mineral hematite. From there, it will proceeded to even higher elevations to inspect layers that contain clays and sulfates.

Getting to the farthest destination (the sulfate unit) will require another 6 km (3.7 mi) of uphill driving. However, this is a short distance compared to the kind of driving the rover has already performed. Moreover, the science team has spent the past four years implementing various methods designed to avoid embedded rocks and other potentially hazardous terrain features.

*MRO image of Gale Crater illustrating the landing location and trek of the Rover Curiosity. Credits: NASA/JPL, illustration, T.Reyes*

It is expected that this drive up Mount Sharp will yield some impressive scientific finds. During its first year on Mars, Curiosity succeeded in gathering evidence in the Gale Crater that showed how Mars once had conditions favorable to life. This included ample evidence of liquid water, all the chemical elements needed for life, and even a chemical source of energy.

By scaling Mount Sharp and examining the layers that were deposited over the course of billions of years, Curiosity is able to examine a living geological record of how the planet has evolved since then. Luckily, the rover’s wheels seem to have more than enough life to make these and (most likely) other scientific finds.

Further Reading: NASA – Mars Exploration

March 22, 2017April 4, 2017 by Evan Gough

SpaceX & NASA Studying 2020 Landing Sites For Dragon

An artist's illustration of SpaceX's Dragon capsule entering the Martian atmosphere. Image: SpaceX

As part of their effort to kick-start the eventual colonization of Mars, SpaceX is sending an unmanned Dragon spacecraft to Mars. Initially, that mission was set for 2018, but is now re-scheduled for 2020. Now, SpaceX says they’re working with NASA to select a suitable landing site for their first Dragon mission to Mars.

At a presentation in Texas on March 18th, Paul Wooster of SpaceX said that they have been working with scientists at NASA’s Jet Propulsion Laboratory (JPL) to identify candidate landing sites on the surface of Mars. In order to aid colonization, the sites need to be:

near the equator, for solar power
near large quantities of ice, for water
at low elevation, for better thermal conditions

But finding a site that meets those conditions is difficult.

According to SpaceNews, the study done with NASA initially recognized 4 regions in Mars’ northern hemisphere, all within 40 degrees of the equator. They are Deuteronilus Mensae, Phlegra Montes, Utopia Planitia, and Arcadia Planitia.

Deuteronilus Mensae

Deuteronilus Mensae (DM) is located between older, cratered highlands and low plains. DM shows evidence of glacial activity in its surface features. In fact, there are still glaciers there, which makes it a desirable source of ice.

Phlegra Montes

Phlegra Montes (PM) is a system of mountains on the Martian surface, over 1300 km across. It’s a complex system of basins, hills, and ridges. They are likely tectonic in origin, rather than volcanic, and the region probably contains large quantities of water ice, perhaps 20 meters below the surface.

Utopia Planitia

Utopia Planitia (UP) is the region where the Viking 2 lander set down in 1976. At 3300 km in diameter, UP is the largest impact basin in the Solar System. In 2016, NASA found a huge deposit of underground ice there. The water is estimated to be the same volume as Lake Superior.

Arcadia Planitia

Arcadia Planitia (AP) is a smooth plain containing fresh lava flows. It also has a large region that was shaped by periglacial processes. This supports the idea that ice is present just beneath the surface, making it a candidate for colonization efforts.

The image below shows the Arcadia Planitia region in relation to some of its surroundings. Colonists at AP might have a great view of Olympus Mons, the largest volcano in the Solar System.

Colonists in Arcadia Planitia (upper left in map) might have a great view of Olympus Mons.

The four areas looked suitable in images from a medium resolution camera (CTX) on the Mars Reconnaissance Orbiter (MRO). But when the High Resolution Imaging Science Experiment (HiRISE) camera on the same orbiter was used to look more closely, the first three locations appeared to be much rockier. According to SpaceNews, Wooster said ““The team at JPL has been finding that, while the areas look very flat and smooth at CTX resolution, with HiRISE images, they’re quite rocky. That’s been unfortunate in terms of the opportunities for those sites.”

The fourth area, Arcadia Planitia, is a more promising site. HiRISE images showed that it is much less rocky and could be a suitable site for the first Dragon mission to Mars.

The Dragon mission to Mars is just the first step for SpaceX. They see themselves as an interplanetary transportation company eventually. SpaceX intends to send a craft to Mars every two years, when the launch window is optimal. SpaceX says they’ll have the ability to deliver one ton of payload to the Martian surface with each Dragon mission.

Their Interplanetary Transport System (ITS) might have the capability to make it to Mars in as little as 80 days, while carrying a payload of up to 450 tons. While still in the very initial stages of design, it may eventually revolutionize our ability to colonize Mars in any meaningful or enduring way. SpaceX envisions a fleet of craft in the ITS which will constantly make the return to trip to Mars.

If that ever happens, we may look at the first Dragon mission to Arcadia Planitia, or another eventual landing site, as the first step.

March 21, 2017April 4, 2017 by Evan Gough

Stephen Hawking Is Going To The Edge Of Space

The VMS Eve (Virgin Mother Ship) carrys VSS Unity (Virgin Spaceship) for its first flight ever over Mojave, CA on Thursday September 8, 2016. Image: Virgin Galactic

Stephen Hawking has spent decades theorizing about the Universe. His thinking on black holes, quantum gravity, quantum mechanics, and a long list of other topics, has helped shape our understanding of the cosmos. Now it looks like the man who has spent most of his adult life bound to a wheel-chair will travel to the edge of space.

In an interview with Good Morning Britain, Hawking said “Richard Branson has offered me a seat on Virgin Galactic, and I said yes immediately.” Hawking added that his “three children have brought me great joy—and I can tell you what will make me happy, to travel in space.”

Stephen Hawking is one of the premier physicists and theorists of our time. Here he is being presented by his daughter Lucy Hawking at the lecture he gave for NASA’s 50th anniversary. Credit: NASA/Paul Alers

It’s all thanks to Richard Branson and his VSS Unity spaceship, which is still under development by The Spaceship Company. The Unity is designed to launch not from a rocket pad, but from underneath a carrier aircraft. By eliminating enormously expensive rocket launches from the whole endeavour, Branson hopes to make space more accessible to more people.

Virgin Spaceship Unity (VSS Unity) glides for the first time after being released from Virgin Mothership Eve (VMS Eve) over the Mojave Desert on 3rd, December 2016. Image: Virgin Galactic

The Virgin Galactic spacecraft is carried to an altitude of about 50,000 feet, then released from its carrier aircraft. Its rocket fires for about 1 minute, which accelerates the craft to three-and-a-half times the speed of sound, then is shut off. Then, according to Virgin Galactic, passengers will experience a “dramatic transition to silence and to true weightlessness.”

As the video shows, the spacecraft is still in glide testing phase, where it is carried to altitude, then released. There is no rocket burn, and the craft glides down and lands at its base.

This spaceflight won’t be Hawking’s first experience with weightlessness, however. To celebrate his 65th birthday, Hawking travelled on board Zero Gravity Corp’s modified Boeing 727 in 2007. At the time, that zero-g flight was in preparation for a trip into sub-orbital space with Virgin Galactic in 2009. But the development of Virgin Galactic’s spacecraft has suffered setbacks, and the 2009 date was not attainable.

Hawking has experienced zero gravity before, when he flew on Zero Gravity Corp’s modified Boeing 727 in 2007. Image: By Jim Campbell/Aero-News Network – http://www.flickr.com/photos/39735679@N00/475109138/ / http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=31873, Public Domain, https://commons.wikimedia.org/w/index.php?curid=3655144

Virgin Galactic’s stated aim is to “democratize space,” albeit at a cost of US $250,000 per person. But somehow I doubt that Hawking will be paying. If anyone has earned a free trip into space, it is Dr. Stephen Hawking.

March 20, 2017December 3, 2018 by Matt Williams

Eye Opening Numbers On Space Debris

Still image taken from a movie, Space debris ? a journey to Earth, to be released April 18th, 2017. Credit: ESA

Orbital debris, otherwise known as “space junk”, is a major concern. This massive cloud that orbits the Earth is the result of the many satellites, platforms and spent launchers that have been sent into space over the years. And as time went on, collisions between these objects (as well as disintegrations and erosion) has created even more in the way of debris.

Aside from threatening satellites and posing a danger to long-term orbital missions – like the International Space Station – this situation could pose serious problems for future space launches. And based on the latest numbers released by the Space Debris Office at the European Space Operations Center (ESOC), the problem has been getting getting worse. Continue reading “Eye Opening Numbers On Space Debris”

March 20, 2017April 4, 2017 by Nancy Atkinson

Ever Wondered What Final Approach To Mars Might Feel Like?

Layered deposits in Uzboi Vallis on Mars, as seen by the HiRISE camera on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona.

We’ve posted several ‘flyover’ videos of Mars that use data from spacecraft. But this video might be the most spectacular and realistic. Created by filmmaker Jan Fröjdman from Finland, “A Fictive Flight Above Real Mars” uses actual data from the venerable HiRISE camera on board the Mars Reconnaissance Orbiter, and takes you on a 3-D tour over steep cliffs, high buttes, amazing craters, polygons and other remarkable land forms. But Fröjdman also adds a few features reminiscent of the landing videos taken by the Apollo astronauts. Complete with crosshatches and thruster firings, this video puts you on final approach to land on (and then take off from) Mars’ surface.

(Hit ‘fullscreen’ for the best viewing)

To create the video, Fröjdman used 3-D anaglyph images from HiRISE (High Resolution Science Imaging Experiment), which contain information about the topography of Mars surface and then processed the images into panning video clips.

Fröjdman told Universe Today he worked on this video for about three months.

“The most time consuming was to manually pick the more than 33,000 reference points in the anaglyph images,” he said via email. “Now when I count how many steps there were in total in the process, I come to seven and I needed at least 6 different kinds of software.”

A new impact crater that was formed between July 2010 and May 2012, as seen by the HiRISE camera on the Mars Reconnaissance Orbiter. This image is part of “A Fictive Flight Above Real Mars” by Jan Fröjdman. Credit: NASA/JPL/University of Arizona.

Fröjdman, a landscape photographer and audiovisual expert, said he wanted to create a video that gives you the feeling “that you are flying above Mars looking down watching interesting locations on the planet,” he wrote on Vimeo. “And there are really great places on Mars! I would love to see images taken by a landscape photographer on Mars, especially from the polar regions. But I’m afraid I won’t see that kind of images during my lifetime.”

Between HiRISE and the Curiosity rover images, we have the next best thing to a human on Mars. But maybe one day…

Fröjdman has previously posted other space-related videos, including video and images of the Transit of Venus in 2012 he took from an airplane, and a lunar eclipse in 2011.

A FICTIVE FLIGHT ABOVE REAL MARS from Jan Fröjdman on Vimeo.