Mars: The planet that lost an ocean’s worth of water

Mars: The planet that lost an ocean’s worth of water

A primitive ocean on Mars held more water than Earth’s Arctic Ocean, and covered a greater portion of the planet’s surface than the Atlantic Ocean does on Earth, according to new results published today. An international team of scientists used ESO’s Very Large Telescope, along with instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility, to monitor the atmosphere of the planet and map out the properties of the water in different parts of Mars’s atmosphere over a six-year period. These new maps are the first of their kind.

The results appear online in the journal Science today.

About four billion years ago, the young planet would have had enough water to cover its entire surface in a liquid layer about 140 metres deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere, and in some regions reaching depths greater than 1.6 kilometres.

“Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,” said Geronimo Villanueva, a scientist working at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, USA, and lead author of the new paper. “With this work, we can better understand the history of water on Mars.”

The new estimate is based on detailed observations of two slightly different forms of water in Mars’s atmosphere. One is the familiar form of water, made with two hydrogen atoms and one oxygen, H2O. The other is HDO, or semi-heavy water, a naturally occurring variation in which one hydrogen atom is replaced by a heavier form, called deuterium.

As the deuterated form is heavier than normal water, it is less easily lost into space through evaporation. So, the greater the water loss from the planet, the greater the ratio of HDO to H2O in the water that remains.

The researchers distinguished the chemical signatures of the two types of water using ESO’s Very Large Telescope in Chile, along with instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility in Hawaii. By comparing the ratio of HDO to H2O, scientists can measure by how much the fraction of HDO has increased and thus determine how much water has escaped into space. This in turn allows the amount of water on Mars at earlier times to be estimated.

In the study, the team mapped the distribution of H2O and HDO repeatedly over nearly six Earth years — equal to about three Mars years — producing global snapshots of each, as well as their ratio. The maps reveal seasonal changes and microclimates, even though modern Mars is essentially a desert.

Ulli Kaeufl of ESO, who was responsible for building one of the instruments used in this study and is a co-author of the new paper, adds: “I am again overwhelmed by how much power there is in remote sensing on other planets using astronomical telescopes: we found an ancient ocean more than 100 million kilometres away!”

The team was especially interested in regions near the north and south poles, because the polar ice caps are the planet’s largest known reservoir of water. The water stored there is thought to document the evolution of Mars’s water from the wet Noachian period, which ended about 3.7 billion years ago, to the present.

The new results show that atmospheric water in the near-polar region was enriched in HDO by a factor of seven relative to Earth’s ocean water, implying that water in Mars’s permanent ice caps is enriched eight-fold. Mars must have lost a volume of water 6.5 times larger than the present polar caps to provide such a high level of enrichment. The volume of Mars’s early ocean must have been at least 20 million cubic kilometres.

Based on the surface of Mars today, a likely location for this water would be the Northern Plains, which have long been considered a good candidate because of their low-lying ground. An ancient ocean there would have covered 19% of the planet’s surface — by comparison, the Atlantic Ocean occupies 17% of the Earth’s surface.

“With Mars losing that much water, the planet was very likely wet for a longer period of time than previously thought, suggesting the planet might have been habitable for longer,” said Michael Mumma, a senior scientist at Goddard and the second author on the paper.

It is possible that Mars once had even more water, some of which may have been deposited below the surface. Because the new maps reveal microclimates and changes in the atmospheric water content over time, they may also prove to be useful in the continuing search for underground water.


Source: European Southern Observatory – ESO


See Comet Lovejoy in Cassiopeia throughout March

See Comet Lovejoy in Cassiopeia throughout March

With a Full Moon in the sky tonight, UK observers can only view C/2014 Q2 Lovejoy by moonlight or in early morning twilight. Fortunately, Comet Lovejoy is still relatively bright in the constellation Cassiopeia and visible in binoculars. Since it is now a circumpolar object, it doesn’t set as seen from the British Isles. C/2014 Q2 merely dips below the north celestial pole around 3 am GMT to within 20° of the northern horizon in the UK, before rising higher in the sky at dawn.

Observers using GoTo telescopes or instruments equipped with digital setting circles can use the following nightly equatorial coordinates to find Comet Lovejoy quickly:

5th March at 8 pm GMT  —  α = 1h 28.6m  δ = +56°37′ (J2000.0)

This finder chart shows C/2014 Q2’s path through the constellation of Cassiopeia during March 2015. Now that Comet Lovejoy is receding from the Sun and the Earth, its motion against the background stars slows to an average of ⅓° per day this month. Note the comet’s close passage to magnitude 2.7 delta (δ) Cassiopeiae, also known as ‘Ruchbah’ on the 15th. The 5° circle represents the field of view of a typical 10×50 binocular for scale. Click the graphic for a full size version suitable for printing. AN graphic by Ade Ashford

This finder chart shows C/2014 Q2’s path through the constellation of Cassiopeia during March 2015. Now that Comet Lovejoy is receding from the Sun and the Earth, its motion against the background stars slows to an average of ⅓° per day this month. Note the comet’s close passage to magnitude 2.7 delta (δ) Cassiopeiae, also known as ‘Ruchbah’ on the 15th. The 5° circle represents the field of view of a typical 10×50 binocular for scale. Click the graphic for a full size version suitable for printing. AN graphic by Ade Ashford

 

If current magnitude predictions hold true, C/2014 Q2 should fade from around magnitude 6 to magnitude 8 by the end of March 2015. This means that Comet Lovejoy is still an easy target for binoculars and small telescopes, especially when moonless skies return around the 8th.

Seek out a dark, safe location with an unobstructed view of the western sky. The comet will be highest above the northwest horizon at the time twilight ends around 8 pm GMT (though note that the Full Moon will be up throughout the hours of darkness). Use the lowest power eyepiece you have when observing C/2014 Q2 with a telescope.

Comet Lovejoy lies in a rich star field in the constellation Cassiopeia, four-fifths of the way from γ Andromedae (Almach) to the prominent W-shaped asterism of Cassiopeia.

Source: Ade Ashford

 

NASA releases new photos showing strange lights on dwarf planet Ceres

NASA releases new photos showing strange lights on dwarf planet Ceres

A NASA spacecraft that’s nearing dwarf planet Ceres has returned new images showing the mysterious lights that have scientists scratching their heads.

The images, released in the form of a GIF on the website for NASA’s Jet Propulsion Laboratory, show at least two strange lights shining brightly as Ceres rotates. They were taken from about 25,000 miles away by NASA’s Dawn spacecraft on its approach to orbit around Ceres. The origin of the lights is unclear at this time, NASA officials said.

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On March 6, Dawn will make history as the first mission to successfully visit a dwarf planet when it finally enters orbit around Ceres.

“Dawn is about to make history,” said Robert Mase, project manager for the mission, in a statement released alongside the images on Monday. “Our team is ready and eager to find out what Ceres has in store for us.”

The surface of Ceres is covered with craters of many shapes and sizes, as seen in this new mosaic of the dwarf planet comprised of images taken by NASA's Dawn mission on Feb. 19, 2015 from a distance of nearly 29,000 miles (46,000 kilometers).

The surface of Ceres is covered with craters of many shapes and sizes, as seen in this new mosaic of the dwarf planet comprised of images taken by NASA’s Dawn mission on Feb. 19, 2015 from a distance of nearly 29,000 miles (46,000 kilometers).

The dwarf planet was first discovered by Sicilian astronomer Father Giuseppe Piazzi in 1801. Since then, it has been classified as a planet, then an astroid, and finally in 2006 was named a “dwarf planet” alongside Pluto, Haumea, Makemake and Eris.

Scientists hope the Dawn mission will help shine light on the origin of the Solar System.

“Both Vesta,” an asteroid, “and Ceres were on their way to becoming planets, but their development was interrupted by the gravity of Jupiter,” said Carol Raymond, deputy project scientist at JPL, in the statement. “These two bodies are like fossils from the dawn of the Solar System, and they shed light on its origins.”

Source: By Brian Ries

NASA’s Curiosity Rover Finds Clues to How Water Helped Shape Martian Landscape

NASA’s Curiosity Rover Finds Clues to How Water Helped Shape Martian Landscape

Observations by NASA’s Curiosity Rover indicate Mars’ Mount Sharp was built by sediments deposited in a large lake bed over tens of millions of years.

This interpretation of Curiosity’s finds in Gale Crater suggests ancient Mars maintained a climate that could have produced long-lasting lakes at many locations on the Red Planet.

“If our hypothesis for Mount Sharp holds up, it challenges the notion that warm and wet conditions were transient, local, or only underground on Mars,” said Ashwin Vasavada, Curiosity deputy project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. “A more radical explanation is that Mars’ ancient, thicker atmosphere raised temperatures above freezing globally, but so far we don’t know how the atmosphere did that.”

Why this layered mountain sits in a crater has been a challenging question for researchers. Mount Sharp stands about 3 miles (5 kilometers) tall, its lower flanks exposing hundreds of rock layers. The rock layers – alternating between lake, river and wind deposits — bear witness to the repeated filling and evaporation of a Martian lake much larger and longer-lasting than any previously examined close-up.

“We are making headway in solving the mystery of Mount Sharp,” said Curiosity Project Scientist John Grotzinger of the California Institute of Technology in Pasadena. “Where there’s now a mountain, there may have once been a series of lakes.”

Curiosity currently is investigating the lowest sedimentary layers of Mount Sharp, a section of rock 500 feet (150 meters) high, dubbed the Murray formation. Rivers carried sand and silt to the lake, depositing the sediments at the mouth of the river to form deltas similar to those found at river mouths on Earth. This cycle occurred over and over again.

“The great thing about a lake that occurs repeatedly, over and over, is that each time it comes back it is another experiment to tell you how the environment works,” Grotzinger said. “As Curiosity climbs higher on Mount Sharp, we will have a series of experiments to show patterns in how the atmosphere and the water and the sediments interact. We may see how the chemistry changed in the lakes over time. This is a hypothesis supported by what we have observed so far, providing a framework for testing in the coming year.”

After the crater filled to a height of at least a few hundred yards, or meters, and the sediments hardened into rock, the accumulated layers of sediment were sculpted over time into a mountainous shape by wind erosion that carved away the material between the crater perimeter and what is now the edge of the mountain.

On the 5-mile (8-kilometer) journey from Curiosity’s 2012 landing site to its current work site at the base of Mount Sharp, the rover uncovered clues about the changing shape of the crater floor during the era of lakes.

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“We found sedimentary rocks suggestive of small, ancient deltas stacked on top of one another,” said Curiosity science team member Sanjeev Gupta of Imperial College in London. “Curiosity crossed a boundary from an environment dominated by rivers to an environment dominated by lakes.”

Despite earlier evidence from several Mars missions that pointed to wet environments on ancient Mars, modeling of the ancient climate has yet to identify the conditions that could have produced long periods warm enough for stable water on the surface.

NASA’s Mars Science Laboratory Project uses Curiosity to assess ancient, potentially habitable environments and the significant changes the Martian environment has experienced over millions of years. This project is one element of NASA’s ongoing Mars research and preparation for a human mission to the planet in the 2030s.

“Knowledge we’re gaining about Mars’ environmental evolution by deciphering how Mount Sharp formed will also help guide plans for future missions to seek signs of Martian life,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program at the agency’s headquarters in Washington.

JPL, managed by Caltech, built the rover and manages the project for NASA’s Science Mission Directorate in Washington.

Source: Jet Propulsion Laboratory
 
Warm Gas Pours ‘Cold Water’ on Galaxy’s Star-Making

Warm Gas Pours ‘Cold Water’ on Galaxy’s Star-Making

Some like it hot, but for creating new stars, a cool cosmic environment is ideal. As a new study suggests, a surge of warm gas into a nearby galaxy — left over from the devouring of a separate galaxy — has extinguished star formation by agitating the available chilled gas.

The unique findings illustrate a new dimension to galaxy evolution, and come courtesy of the European Space Agency’s Herschel space observatory, in which NASA played a key role, and NASA’s Spitzer and Hubble space telescopes.

Astronomers want to understand why galaxies in the local universe fall into two major categories: younger, star-forming spirals (like our own Milky Way), and older ellipticals, in which fresh star making has ceased. The new study’s galaxy, NGC 3226, occupies a transitional middle ground, so getting a bead on its star formation is critical.

“We have explored the fantastic potential of big data archives from NASA’s Hubble, Spitzer and ESA’s Herschel observatory to pull together a picture of an elliptical galaxy that has undergone huge changes in its recent past due to violent collisions with its neighbors,” said Philip Appleton, project scientist for the NASA Herschel Science Center at the California Institute of Technology in Pasadena and lead author of a recent Astrophysical Journal paper detailing the results. “These collisions are modifying not only its structure and color, but also the condition of the gas that resides in it, making it hard — at the moment — for the galaxy to form many stars.”

NGC 3226 is relatively close, just 50 million light-years away. Several star-studded, gassy loops emanate from NGC 3226. Filaments also run out from it and between a companion galaxy, NGC 3227. These streamers of material suggest that a third galaxy probably existed there until recently — that is, until NGC 3226 cannibalized it, strewing pieces of the shredded galaxy all over the area.

A prominent piece of these messy leftovers stretches 100,000 light-years and extends right into the core of NGC 3226. This long tail ends as a curved plume in a disk of warm hydrogen gas and a ring of dust. Contents of the tail, thought to be the debris from that departed galaxy, are falling into NGC 3226, drawn by its gravity.

In many instances, adding material to galaxies in this manner rejuvenates them, triggering new rounds of star birth thanks to gas and dust gelling together. Yet data from the three telescopes agree that NGC 3226 has a very low rate of star formation. It appears that in this case, the material falling into NGC 3226 is heating up as it collides with other galactic gas and dust, quenching star formation instead of fueling it.

The outcome could have been different, as NGC 3226 hosts a supermassive black hole at its center. The influx of gas and dust might have ended up just feeding the black hole, setting off energetic outpourings as the material crashed together while whirling toward its doom. Instead, the black hole in NGC 3226’s core is just snacking, not gorging, as the material has spread out in the galaxy’s central regions.

“We are discovering that gas does not simply funnel down into the center of a galaxy and feed the supermassive black hole known to be lurking there,” Appleton said. “Rather, it gets hung up in a warm disk, shutting down star formation and probably frustrating the black hole’s growth by being too turbulent at this point in time.”

NGC 3226 is considered something between a youthful “blue” galaxy and an old “red” galaxy. The colors refer to the predominantly galactic blue light radiated by giant, young stars — a telltale sign of recent star formation — and the reddish light cast by mature stars in the absence of new, blue ones.

This intermediary galaxy illuminates how galaxies accruing fresh gas and dust can bloom with new stars or have their stellar factories close shop, at least temporarily. After all, as the warm gas flooding NGC 3226 cools to star-forming temperatures, the galaxy should get a second wind.

Intriguingly, ultraviolet and optical light observations suggest that NGC 3226 may have produced more stars in the past, leading to its current intermediate color, somewhere between red and blue. The new study indicates that those traces of youth must indeed be lingering from higher levels of star formation, before the infalling gas scrambled the scene.

“NGC 3226 will continue to evolve and may hatch abundant new stars in the future,” said Appleton. “We’re learning that the transition from young- to old-looking galaxies is not a one-way, but a two-way street.”

Other authors of the report are: C. Mundell of Liverpool John Moores University, England; M. Lacy of National Radio Astronomy Observatory, Charlottesville, Virginia; V. Charmandaris of University of Creete, Greece; P-A. Duc of CEA-Saclay, France; U. Lisenfeld of University of Granda, Spain; and T. Bitsakis, K. Alatalo, L. Armus and P. Ogle of Caltech.

Herschel is a European Space Agency mission, with science instruments provided by consortia of European institutes and with important participation by NASA. While the observatory stopped making science observations in April 2013, after running out of liquid coolant, as expected, scientists continue to analyze its data. NASA’s Herschel Project Office is based at NASA’s Jet Propulsion Laboratory, Pasadena, California. JPL contributed mission-enabling technology for two of Herschel’s three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at Caltech, supports the U.S. astronomical community.

JPL manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech.

Caltech manages JPL for NASA.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.

Source: Jet Propulsion Laboratory

 

Why NASA’s Orion is critical for our future in space

Why NASA’s Orion is critical for our future in space

NASA is set to embark on a journey that will usher in a new era for Americans in space, but we’ll have to wait for another day to see it happen.

The space agency was set to launch its Orion spacecraft on Thursday for a test flight around the Earth. The original launch time was set for 7:05 a.m. ET, but the launch was pushed back multiple times due to winds, some minor technical issues and, at one point, a stray boat.

NASA eventually scrubbed Thursday’s launch. The second attempt will be on Friday with the same launch window of 7:05 a.m. to 9:44 a.m. ET.

Orion is unmanned — for now. The spacecraft is capable of carrying humans deeper into space, beyond the moon. NASA’s ultimate goal for Orion is a roundtrip manned Mars mission.

How the test flight will work

NASA’s Orion historic test flight will last less than five hours.

Orion is aiming for two orbits on its first run. On the second lap around Earth, the spacecraft should reach a peak altitude of 3,600 miles, high enough to ensure a re-entry speed of 20,000 mph. NASA will test Orion’s high-speed re-entry systems such as avionics, attitude control, parachutes and the heat shield.

Splashdown will be in the Pacific off the Mexican Baja coast, where Navy ships are waiting for the recovery.

The US Navy and NASA recovery teams are on station off the cost of California and ready to recover Orion after landing.

The US Navy and NASA recovery teams are on station off the cost of California and ready to recover Orion after landing.

Lockheed Martin Corp., which is handling the $370 million test flight for NASA, opted for the powerful Delta IV rocket this time around. Future Orion missions will rely on NASA’s still-in-development megarocket, known as SLS, or Space Launch System. Orion’s first launch with SLS is targeted for 2018.

The video below shows how this test flight will work for Orion:

NASA’s last trip beyond low-Earth orbit in a vehicle built for astronauts was Apollo 17 in December 1972. Though the space agency is using new technology for Orion, which can carry six astronauts, it learned a lot from Apollo, which transported three.

What is so important about Mars

Mars is a harsh planet. It’s choked with dust. There’s no oxygen. It has a paper-thin atmosphere. It’s dry, and the temperature there is always well below freezing.

There are miles of sweeping deserts, plunging canyons and mountains higher than the tallest on Earth. But the landscape all painted with the same color palette—rust orange, milk chocolate browns and muted reds. And it never ends. Even the sky is a hazy orange almost all day.

But Mars wasn’t always this way. Mars has a past — one with water and life. On ancient Mars, you would have woken up to a sky that always seemed as though it were in limbo between sunrise and sunset. At noon, you would have seen bright pink with hints of orange. There was water, but it probably wasn’t blue.

The story of Mars is actually one of an underdog. Had it not been for its small size, this planet’s atmosphere would have stayed intact and may have very well continued to thrive.

So, what happened to our neighbor? And, perhaps more importantly for humans, does Earth face a similar fate? How Mars met this violent, desolate end is still a mystery, one that we can probably only solve by getting humans there.

After the $2.5 billion Curiosity rover, which is still trekking around and doing science on Mars, President Obama vowed to get a manned mission off the ground in the 2020s.

Spacesuit engineers demonstrate how four crew members would be arranged for launch inside the Orion spacecraft.
Spacesuit engineers demonstrate how four crew members would be arranged for launch inside the Orion spacecraft.
Source: By Amanda Wills / Mashable