Mars’ oceans formed much earlier than previously believed

A new study gives compelling evidence that Mars once had a series of ancient oceans.

Mars’ ancient, now dried up oceans were older and much more shallow than previously believed, according to new research published in the journal Nature.

The study comes from researchers at the University of California, Berkeley, who connected the existence of Mars’ early oceans to the rise of our solar system’s largest volcanic system, Tharsis. That link is important because it suggests that global warming allowed liquid water to exist on the Red Planet.

In the new study, the team built a model that helps explain how water first came to the Red Planet. They believe the oceans formed 3.7 billion years ago, which puts them right before or at the same time as Tharsis. As the mountains were much smaller back then, they did not disrupt the planet as much as they did later on. That means the seas would have been relatively shallow, holding just half the water previous estimates assumed.

“The assumption was that Tharsis formed quickly and early, rather than gradually, and that the oceans came later,” explained study co-author Michael Manga, a professor at the University of California, Berkeley, according to Phys.org“We’re saying that the oceans predate and accompany the lava outpourings that made Tharsis.”

The team’s research showed that Tharsis spewed gas into the atmosphere, a process that caused the global warming that created liquid water. The volcanic eruptions also generated channels that allowed underground water to reach the surface and fill the northern plains.

While some people are skeptical that Mars once had oceans, this research gives compelling evidence for the bodies of water. In addition to the research, scientists also found a series of irregular shorelines that suggest the volcano system depressed and deformed the land as it grew. Such a process may have created natural irregularities in rock height, especially if the oceans formed during Tharsis’ early years.

Though more work needs to be done, this research is a good start to understanding Mars’ oceans. The team plans to continue mapping and dating to see what else they can discover about the Red Planet’s past, and they hope NASA’s next Mars lander, InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) will help them in such endeavors. 

“It could potentially detect the presence of subsurface frozen water, which could be a remnant of a past ocean,” said  lead author Robert Citron, a planetary scientist at the University of California, Berkeley, according to Space.com.

NASA papers guide search for extraterrestrial life

Network of scientists discuss search for biosignatures on exoplanets.

Five papers produced by a two-year interdisciplinary study on finding life beyond Earth provide guidelines on the search for extraterrestrial life in both our solar system and others.

Organized by NASA’s Nexus for Exoplanet System Science (NExSS), the papers include contributions by astrobiologists, planetary scientists, Earth scientists, heliophysicists, astrophysicists, chemists, and biologists.

Scientists with NASA’s Virtual Planetary Laboratory (VPL) at the University of Washington (UW) focused on a multidisciplinary approach to finding life beyond Earth.

“For life to be detectable on a distant world, it needs to strongly modify its planet in a way that we can detect. But for us to correctly recognize life’s impact, we also need to understand the planet and star–that environmental context is key,” noted Virginia Meadows of UW and principal investigator of VPL.

More than 3,700 exoplanets have been discovered since 1992. NExSS was created by NASA to draw from various scientific fields in searching for biosignatures, signs of extraterrestrial life.

A key accomplishment of NExSS has been facilitating communication between scientists searching for signs of microbial life on other solar system worlds and those looking for such signs on exoplanets.

The first of the papers, all published in the journal Astrobiology, identifies two types of signals scientists can use to search for life. One comes in the form of a planet’s atmospheric gases, such as oxygen, which can be produced by life ranging from microbes to plants. The other is through the type of light reflected by life forms, such as the colors of leaves.

These signatures can already be seen from Earth orbit. A new generation of telescopes, such as the James Webb Space Telescope (JWST), will let scientists probe exoplanets’ atmospheres.

In the second paper, researchers discuss “false positives” or signals that can erroneously lead scientists to conclude a planet has life, and “false negatives,” where signs of life could be missed. For example, oxygen can be produced by life as well as by non-living processes.

“There are lots of things in the universe that could potentially put two oxygen atoms together, not just photosyntheseis–let’s try to figure out what they are,” Meadows emphasized. “Under what conditions are they more likely to happen, and how can we avoid getting fooled?”

Understanding potential biosignatures is the focus of the third and fourth papers, in which researchers apply lessons learned from Earth to the exploration of other planets. Based on factors such as the chemistry in a planet’s atmosphere, a planet’s climate, and the presence of oceans and continents, scientists can assign a probability score as to whether that planet is likely to harbor life.

Biologists and geologists will have to work together to interpret findings about individual planets to determine whether life can adapt to their particular environments, explained Nancy Kiang, a VPL member and biometeorologist at NASA’s Goddard Institute for Space Studies in New York.

The fifth paper focuses on ground- and space-based telescopes, both current and future, that will be used to search for signs of life beyond Earth.

Milky Way has merged with numerous galaxies

Studying globular clusters gives scientists insight into galaxy’s history.

Since its formation billions of years ago, the Milky Way has merged with 12 galaxies of similar size and three dwarf galaxies, according to a study by astronomers at the University of Heidelberg in Germany.

The researchers arrived at this conclusion by studying globular clusters, dense clusters comprised of hundreds of thousands of stars, in the Milky Way’s halo.

A galaxy’s halo is spherical region of stars, gas, and dust extending beyond its main structure. It typically contains numerous globular clusters and older, metal-poor stars.

To learn more about the Milky Way’s long history, the research team studied 96 globular clusters orbiting the center of the galaxy, measuring the ages and levels of heavy elements in their stars.

Galaxies with large numbers of stars containing heavy elements are typically older than those with mostly metal-poor stars, as the former have had more time to merge with and devour other galaxies in their neighborhoods.

The Milky Way’s globular clusters were found to contain an abundance of metal-rich stars, indicating the galaxy has been merging with other galaxies for as long as 12 billion years.

In addition to having collided and merged with many galaxies of roughly its size, the Milky Way has also devoured at least two dwarf galaxies, the research team concluded, based on their discovery of 25 globular clusters containing metal-poor stars.

Currently, the galaxy is in the process of merging with the Sagittarius dwarf galaxy, one of nine satellite galaxies in orbit around the Milky Way. Completion of the merger will occur over approximately 100 million years, during which the Milky Way’s powerful gravitational pull will tear the much smaller Sagittarius dwarf galaxy apart.

Suspected to harbor some dark matter, the Sagittarius dwarf galaxy survived several previous collisions with our galaxy, the researchers found.

Remnants of galaxies devoured by the Milky Way exist in the form of stellar streams, which the researchers observed with the 570-megapixel Dark Energy Camera at the Cerro Tololo Inter-American Observatory in Chile.

Based on these stellar streams’ positions and trajectories, the researchers were able to determine they originated in other galaxies that merged with the Milky Way.

A paper on these findings has been accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.

K2 data reveals nearly 80 exoplanet candidates

Quick data analysis will enable scientists to confirm planets’ existence through follow up observations.

Scientists have discovered nearly 80 exoplanet candidates in the latest data returned by K2, NASA’s extended planet-hunting mission.

During K2’s 16th and 17th observation periods, known as C16 and C17, K2 looked at approximately 50,000 stars. Each observation, in which the telescope studies one patch of the sky, lasts for 80 days.

One particularly noteworthy planet candidate orbits the brightest star ever studied by K2. Known as HD 73344, the star, which is located approximately 114 light years from Earth, is orbited by a “hot Neptune” type planet that circles it every 15 days.

Estimated to be around 2.5 times the size of Earth and about 10 Earth masses, the planet has an estimated temperature of 2,000 degrees Fahrenheit (1,200-1,300 degrees Celsius), which is close to the temperature of lava in an erupting volcano.

“We think it would probably be more like a smaller, hotter version of Uranus or Neptune,” said study co-leader Ian Crossfield of MIT.

The science team that analyzed the latest K2 data did so in record time, using technological tools developed at MIT to help them sift through the graphs, known as light curves, within just two weeks of their return by K2.

This type of analysis ordinarily takes several months to a year.

Such quick detection of planet candidates allows astronomers to follow up on the findings by observing the planet candidates with ground-based telescopes.

Quicker follow up observations make it easier for scientists to detect additional transits, from which they confirm candidate planets actually exist.

“We found one of the most exciting planets that K2 has found in its entire mission, and we did it more rapidly than any effort has done before. This is showing the path forward for how the TESS mission is going to do the same thing in spades, all over the entire sky, for the next several years,” Crossfield emphasized.

TESS, which stands for Transiting Exoplanet Survey Satellite, is NASA’s new planet-hunting space observatory, which was launched on April 18 of this year. Like Kepler, it will use the transit method to search for planets but will observe an area of the sky 400 times larger than that studied by Kepler.

In a paper on their findings published in The Astronomical Journal, the researchers note, “Our experience with four years of K2 data leads us to believe that most of these are indeed real planets, ready to be confirmed or statistically validated.”

In addition to finding the planet candidates, the scientists who analyzed the data also discovered a supernova in another galaxy and possible signatures of pulsating stars.

Future humans could overcome expansion of the universe

Dyson spheres could be used to anchor stars within the Milky Way.

Existential threats to humanity range from urgent, to a distant possibility. One such remote threat is the accelerating expansion of the universe. While most wouldn’t consider this a real threat, particle physicist, Dan Hooper, at the Fermi National Accelerator Laboratory, points out why it is a threat we should consider.

He points out that things beyond the cosmic horizon—the maximum distance that light can travel to us within the age of the universe—are beyond our ability to study, or influence. Stars, galaxies, even civilizations are beyond the cosmic horizon, and beyond our ability to contact or see them. According to an article in MIT Technology Review discussing Hooper’s theory, the cosmic horizon is changing and this will affect our neighborhood in the universe, which astronomers call the Local Group. The Local Group (50 nearby galaxies bound to the Milky Way) will be humanity’s home for the foreseeable future. But these galaxies may not always be within our reach to possibly colonize, as the accelerating expansion of the universe sends galaxies over the horizon at a rate that’s increasing.

As Hooper explains, “over the next approximately 100 billion years, all stars residing beyond the Local Group will fall beyond the cosmic horizon and become not only unobservable, but entirely inaccessible.” This eventuality would interfere with humanity’s ability to exploit ever more stars for energy. However, Hooper believes there is a way to mitigate the effects of an expansion. He believes that an advanced civilization could build a Dyson sphere that emits waste radiation in a specific direction to accelerate the sphere—and the star it contains—in the opposite direction of the acceleration. Over time, this technology could be used to gather stars as a source of energy, keeping them inside the cosmic horizon. So, potential problem solved? Well, as the article acknowledges, first the assumption that the expansion of the universe is accelerating would have to be correct.

Kuiper Belt asteroid likely originated in region between Mars and Jupiter

Object’s carbon-rich composition, unlike that of most KBOs, reflects its origin.

A carbon-rich asteroid discovered in the Kuiper Belt likely originated in the asteroid belt between Mars and Jupiter and was at some point ejected from its original orbit, according to an international team of astronomers.

Kuiper Belt Object (KBO) 2004 EW95, initially found more than a decade ago, was recently found to be carbonaceous when viewed with the Hubble Space Telescope (HST) during routine observations.

Followup studies of the asteroid with the European Southern Observatory’s (ESO) Very Large Telescope (VLT) confirmed its carbonaceous composition.

Although 2004 EW95 is both small and distant, scientists were able to determine its composition by measuring its reflectance spectrum, the pattern of light wavelengths it reflects, which is very different from that of most KBOs.

Typical KBO spectra are featureless and reveal little about the objects.

“The reflectance spectrum of 2004 EW95 was clearly distinct from the other observed outer solar system objects,” emphasized Tom Seccull of Queens University in Belfast, who led the study. “It looked enough of a weirdo for us to take a closer look.”

That closer look was done using two of the VLT’s sensitive spectrographs, which reveals more details about light patterns reflected by objects, enough for scientists to learn their compositions.

Just 186.4 miles (300 km) wide and located four billion km from Earth, the asteroid was difficult to detect and measure even with the most sophisticated and sensitive instruments.

Two specific features in 2004 EW95’s spectra indicated the presence of ferric oxides and phyllosilicates, substances never previously seen in any KBO, suggesting this asteroid formed in the inner solar system.

During its early years, the solar system was a much more active and violent place, with regular impacts of small objects that flung some into distant orbits beyond Neptune and Pluto.

Computer models of the Kuiper Belt confirm it harbors a small number of asteroids that originated in the belt between Mars and Jupiter.

“Given 2004 EW95’s present day abode in the icy outer reaches of the solar system, this implies that it has been flung out into its present orbit by a migratory planet in the early days of the solar system,” Seccull stated.

“While there have been previous reports of other ‘atypical’ Kuiper Belt Object spectra, none were confirmed to this level of quality,” said ESO astronomer Olivier Hainaut, who did not take part in the study. “The discovery of a carbonaceous asteroid in the Kuiper Belt is a key verification of one of the fundamental predictions of dynamical models of the early solar system.”

Findings of the study have been published in the journal Astrophysical Journal Letters.

G-objects may have come from supermassive black hole, study reports

Mysterious celestial bodies known as G-objects may have formed at the Milky Way’s galactic center.

Strange celestial structures that look like dust clouds but act like stars may have been created by the supermassive black hole at the center of the Milky Way, according to unpublished research set to be presented at the American Astronomical Society.

Scientists have spent a lot of time studying the odd bodies — known as G-objects — in order to figure out how they operate. In the recent analysis, researchers from the University of California, Los Angeles discovered three additions to the class and may have shed light on how the odd objects first formed.

Scientists first noticed two of the objects in 2004 and 2012. Further study revealed the bodies, which produce red light and appear to be quite cool, are likely surrounded by dust.

However, the first two G-objects have wandered near the Milky Way’s supermassive black hole without being torn apart. As a result, they have to be denser than a dust cloud. That property is why scientists believe they are actually stars surrounded by gas.

“They’re weird because they are not gas nebulae, they’re not stars, so we think they’re something in the middle, a stellar object surrounded by gas and dust,” study author Anna Ciurlo, an astronomer at the University of California Los Angeles, told Newsweek, “like a star that’s been puffed up.”

As the objects sit so close to the black hole, astronomers also believe that is where they came from. Previous research suggests black holes can encourage closely-paired stars to collide more quickly than they would normally. It is possible such collisions create G-objects.

If that turns out to be true, G-objects may be more common than previously believed. In addition, it would explain why there are so many young stars at the Milky Way’s galactic center.

The team collected the new information by analyzing 12 years’ worth of observations of the center of the Milky Way. Though scientists have spent a lot of time analyzing the region, the new study looked at the data to answer entirely new questions.

The findings are a step to better understanding the region, but there is still a long way to go. Scientists hope to continue their analysis of G-objects to better determine how they work and what their existence means for the center of our galaxy.

“Understanding G-objects can teach us a lot about the Galactic Center’s fascinating and still mysterious environment,” added Ciurlo according to Universe Today. “There are so many things going on that every localized process can help explain how this extreme, exotic environment works.”

TESS images star field after lunar flyby

Stunning image is just a fraction of the amount of sky the planet-hunting probe will photograph.

NASA’s Transiting Exoplanet Survey Satellite (TESS), which launched from Cape Canaveral on April 18, took its first photograph on May 17 after passing within about 5,000 miles of the Moon.

Snapped during a test of one of the probe’s four cameras, the two-second exposure features a field of more than 200,000 stars centered on the constellation Centaurus.

Beta Centauri, a bright star in Centaurus, is visible on the lower left of the image, while part of the Coalsack Nebula can be seen in the top right corner.

A successor to the Kepler Space Telescope, TESS will observe nearly the whole sky in a search for exoplanets transiting, or passing in front of, their host stars. The space observatory is expected to discover thousands of new planets and gather information about them that will be used determine which have the best chances of being habitable for life.

These planets’ atmospheres will be subsequently studied with NASA’s James Webb Space Telescope (JWST), now scheduled to launch in 2020.

The lunar flyby gave the spacecraft a gravity assist to propel it to its orbital destination.

Using all of its four cameras, TESS will cover four times as much sky as it did in the May 17 image.

The spacecraft will release its first “science quality” photograph, also known as a “first light” image, next month.

One more thruster burn, scheduled for May 30, will send TESS to its extremely elliptical orbit around the Earth, an orbit that will enable it to observe large sections of the sky continuously during its two-year mission.

Actual science operations will start after the spacecraft reaches its targeted orbit and camera calibrations are completed.

 

Jupiter may have sent water to Earth

Expanding gas giants in early solar system may have sent water-rich objects in Earth’s direction.

Jupiter and the solar system’s other gas giant planets may have sent water to early Earth by hurling hydrogen-rich asteroids and planetesimals into the inner solar system.

Four-and-a-half billion years ago, the solar system’s planets formed from a cloud of gas left over from the Sun’s formation. Some of that gas remained in place for several million years. As its temperature rose, hydrogen became trapped in distant, outer solar system objects.

Uranus and Neptune likely formed closer to the Sun and migrated outward, triggering impacts between objects, especially icy ones, in what became known as the Late Heavy Bombardment.

Scientists theorize Jupiter and Saturn traveled inward through the asteroid belt after forming, then changed course and headed outward, in the process sending asteroids on a collision course with Earth.

According to a computer model developed by Sean Raymond of the University of Bordeaux in France and Andre Izidoro of NASA’s Astrobiology Institute in Mountain View, California, the gas giants, as they grew and accreted more material, increased their gravitational pulls, perturbing proto-planets near them. Influenced by the remaining nebular gas, some of these carbon- and water-rich asteroids were flung into the asteroid belt between Mars and Jupiter.

“This is the best way to get these volatiles into the terrestrial planet forming region,” noted Conel Alexander, a meteorite specialist at the Carnegie Institution for Science in Washington, DC.

Significantly, Earth’s water matches that of outer solar system asteroids more than it matches that of the inner, drier asteroids.

The computer model showed three waves of icy objects sent in Earth’s direction, one that occurred when Jupiter swelled up, another when Saturn did so, and a third when Uranus and Neptune migrated inward only to be blocked by Jupiter and Saturn and sent back int the outer solar system.

Because this model indicates that in the process of formation, any gas giants would send water-rich material inward toward their star’s habitable region, it could help scientists find watery exoplanets.

“I think the coolest thing is that it basically implies for any exo-solar system where you have giant planets and terrestrial planets, those giant planets would send water inward to the terrestrial planets,” said David O’Brien of the Planetary Science Institute (PSI) in Tucson, Arizona.

“That opens up a lot of possibilities for habitable planet studies.”

A paper on the study has been published in the journal Icarus.

Martian dust storm causes loss of contact with Opportunity rover

Lack of access to sunlight means solar panels are unable to recharge rover’s weakening batteries.

Enveloped by a dust storm that has been raging near it since late May, NASA’s Opportunity rover failed to make contact with Earth during a planned check-in, indicating its power levels may be dangerously low.

One of two identical rovers that arrived on the Red Planet in 2004 on a 90-day mission, Opportunity has been exploring Mars for more than 14 years. Its twin, Spirit, functioned until June 2010, when one of its wheels got stuck in Martian terrain, putting it in a position where it could not get the necessary sunlight to recharge its batteries during winter.

In its near decade-and-a-half on the Red Planet, Opportunity has survived several dust storms, including a powerful one in 2007, when mission control halted communications for four days to save power.

First observed by NASA’s Mars Reconnaissance Orbiter (MRO) on May 30, the current dust storm started near Perseverance Valley, Opportunity’s current location. It rapidly spread and became more powerful to the point that it now covers a quarter of the entire planet.

Within a week of the storm’s start, the rover was engulfed in dust. Opportunity is now in perpetual darkness, as its solar panels are not getting the necessary sunlight to recharge its batteries.

Between June 2 and 10, the rover’s power levels plummeted from 645 watt-hours to 22-watt hours. The power drop triggered Opportunity to put itself in “low power fault mode,” shutting down everything but its internal clock.

Once the storm abates and its solar panels get sufficient sunlight to recharge its batteries, Opportunity will emerge from this low-power state and automatically attempt to contact Earth.

Additional power depletion could cause Opportunity to shut down its internal clock. If that happens, it will still be able to contact Earth when conditions improve, but the timing of its contact attempts will be much less predictable.

The fact that the rover failed to make its last scheduled contact indicates it likely has shut off its internal clock, putting itself in a state where communication is not possible.

Scientists now expect the dust storm to continue growing and envelop the whole planet within the next several days.

During contact with mission control last week, Opportunity measured its internal temperature at minus 20 degrees Fahrenheit (minus 29 degrees Celsius). Cold temperatures could damage and even possibly destroy Opportunity’s batteries.

While the dust around Opportunity is thicker than it was during any previous dust storm, Martian seasonal changes could save it from freezing.  Summer is approaching, meaning temperatures are warming. Temperatures are unlikely to drop below minus 33 degrees Fahrenheit (minus 36 degrees Celsius).

Opportunity is capable of withstanding temperatures as low as minus 67 degrees Fahrenheit (minus 55 degrees Celsius).

John Callas of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, and Opportunity project manager, said he remains optimistic about the rover’s ability to survive the storm.