Tag: science

New paper: Underlying ice layer seen in Martian gullies at LOW mid-latitudes

2:18 pm

Snow on Mars?
Click to see full image.

In a paper just published, scientists are proposing that bright areas seen in the low mid-latitude gullies on Mars are the underground ice table newly exposed as surface dust is removed.

This paper is a reiteration in more detail of a previous presentation [pdf] by these same scientists at the 2019 the 50th Lunar and Planetary Science Conference in Texas and reported here in March 2019.

The image to the right, from the paper, was taken by the high resolution camera of Mars Reconnaissance Orbiter (MRO) in 2009, and has been cropped to post here. The white streaks are what the scientists propose is that exposed underground ice table. At 32.9 south latitude, this particular gully would be the closest to the equator that such an ice layer has been identified. All the previous ice layer discoveries have been in the ice scarps found at latitudes above 50 degrees. As the paper’s lead author, Aditya Khuller at Arizona State University, explained in to me in an email, “We believe we are seeing exposures of dusty ice that likely originated as dusty snow.” From their paper:

We suggest … that the light-toned materials are exposed H2O ice. … [T]he appearance, and then subsequent disappearance of these light-toned materials, suggests that they are some form of volatile, such as dusty ice, rather than dust alone. … [The appearance] of these light-toned materials is similar to the >100m thick, light-toned ice deposits exposed on steep mid-latitude scarps, indicating that these materials are probably also ice, with some amount of dust on, and within the ice.

The layer would have likely been laid down as snow during a time period (a long time ago) when the rotational tilt of Mars, its obliquity, was much higher than today’s 25 degrees. At that time the mid-latitudes were colder than the poles, and water was sublimating from the polar ice caps to fall as snow in the mid-latitudes.

The overview map below reveals some additional intriguing possibilities.
» Read more

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UAE releases first Al-Amal image of Mars

9:45 am

Al-Amal's first Mars image
Click for full image.

The new colonial movement: The leader of the United Arab Emirates (UAE) yesterday released on his twitter feed the first photo of Mars that was beamed back from its Al-Amal (“hope” in English) orbiter, taken shortly after achieving orbit.

That photo is to the right, cropped and reduced to post here. From the article at the link:

[The photo] was captured by Hope’s EXI instrument from an altitude of 24,700 km (15,350 miles) above the Martian surface at 20:36 GMT on Wednesday – so, one day after arriving at the Red Planet.

The north pole of Mars is in the upper left of the image. At centre, just emerging into the early morning sunlight, is Olympus Mons, the largest volcano in the Solar System. Look right on the boundary between night and day, the so-called terminator.

The three shield volcanoes in a line are Ascraeus Mons, Pavonis Mons, and Arsia Mons. Look east, to the limb of the planet, and you can see the mighty canyon system, Valles Marineris. It’s part covered by cloud.

Right now the spacecraft’s orbit is very eccentric, ranging from 600 to 30,000 miles above the Martian surface. After several orbital trims, Al-Amal will end up in an orbit about 14,000 by about 27,000 miles, with an inclination of about 25 degrees. From that high orbit it will then focus on studying the Martian atmosphere.

Thus, future images will likely be similar to this, global and mostly aimed at tracking visible phenomenon in the atmosphere (dust storms and clouds).

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Rover update: The rovers are coming! The rovers are coming!

12:52 pm

With the imminent landing on Mars of both the American rover Perseverance only days away on February 18th followed by China’s rover in April, I think it time for a new rover update, not only providing my readers a review of the new landing sites but a look at the most recent travels of Curiosity on Mars and Yutu-2 on the Moon.

Curiosity

Curiosity's view of the base of Mount Sharp, February 12, 2021
Click for full resolution image.

Overview map of Curiosity's most recent and future travels

The panorama above, made from four images taken by Curiosity’s right navigation camera on February 12, 2021 (found here, here, here, and here), looks south to the base of Mount Sharp, now only a short distance away. The yellow lines on the overview map to the right show the area this panorama covers. The white line indicates Curiosity’s previous travels. The dotted red line in both images shows Curiosity’s planned route.

The two white dots on the overview map are the locations of the two recurring slope lineae along Curiosity’s route, with the plan to get reasonable close to the first and spend some time there studying it. These lineae are one of Mars’ most intriguing phenomenon, seasonal dark streaks that appear on slopes in the spring and fade by the fall. There are several theories attempting to explain their formation, most proposing the seepage of a brine from below ground, but none has been accepted yet with any enthusiasm.
» Read more

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Possible exoplanet detected in habitable zone around Alpha Centauri A?

10:47 am

The uncertainty of science: Scientists have detected faint evidence that suggests the existence of a Neptune-sized exoplanet circling the sunlike star Alpha Centauri A.

After analyzing 100 hours of data gathered by NEAR in May and June of 2019, the scientists detected a thermal fingerprint in the habitable zone of Alpha Centauri A. The signal potentially corresponds to a roughly Neptune-size world orbiting between 1 and 2 astronomical units (AU) from the star, study team members said. (One AU, the average Earth-sun distance, is about 93 million miles, or 150 million kilometers.)

But that planet has not yet been confirmed, so it remains a candidate for now.

This result is very uncertain at this moment, so we should constrain our enthusiasm. If true, however, it would signal the possibility of more exoplanets circling the stars of the nearest stellar system. Alpha Centauri is actually three stars, a binary of two sunlike stars circled at great distance by the red dwarf Proxima Centauri. Scientists already think there are exoplanets circling Proxima, with one about the size of Earth.

What makes this particular interesting, if true, is that the exoplanet was detected not by the slight wobble its gravity caused in the star, or by a transit across the face of the star, but by its own light. If the detection is real, this would be I think the first time that an exoplanet has been seen directly, even if that detection comprises a few tiny pixels of light.

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Europa Clipper to fly on commercial rocket, not SLS

11:30 pm

NASA managers have now decided unequivocally to not use SLS to launch Europa Clipper, and will instead choose a commercial rocket in about a year.

During a Feb. 10 presentation at a meeting of NASA’s Outer Planets Assessment Group (OPAG), leaders of the Europa Clipper project said the agency recently decided to consider only commercial launch vehicles for the mission, and no longer support a launch of the spacecraft on the SLS.

“We now have clarity on the launch vehicle path and launch date,” Robert Pappalardo, project scientist for Europa Clipper at the Jet Propulsion Laboratory, said. That clarity came in the form of a Jan. 25 memo from NASA’s Planetary Missions Program Office to “immediately cease efforts to maintain SLS compatibility” and move forward with a commercial launch vehicle, or CLV, he said.

Though this decision was expected following the approval of the most recent congressional budget for NASA, which contained language allowing NASA to abandon SLS if it thought it wise, this decision continues the string of recent stories that all point toward the eventually abandonment of SLS itself.

At the moment the rocket most likely to win the contract is the Falcon Heavy.

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Scientists confirm distance to farthest known solar system object

2:46 pm

Scientists have now confirmed that the large asteroid dubbed Farfarout (about 250 miles across) is presently about 132 astronomical units from the Sun (about 12 billion miles), making it the farthest known solar system object.

Its orbit however is far from circular, and it isn’t presently even at its farthest point in that orbit.

[T]he orbit of Farfarout is quite elongated, taking it 175 au from the Sun at its farthest point and around 27 au at its closest, which is inside the orbit of Neptune. Because its orbit crosses Neptune’s, Farfarout could provide insights into the history of the outer Solar System. “Farfarout was likely thrown into the outer Solar System by getting too close to Neptune in the distant past,” said Trujillo. “Farfarout will likely interact with Neptune again in the future since their orbits still intersect.”

The astronomers expect to discover more such objects in the coming years that will even eclipse this one in distance.

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Inexplicable ridges in Hellas Basin on Mars

2:07 pm

Sinuous ridge in Hellas Basin
Click for full image.

Time for some more cool but mysterious Martian images! The photo to the right, rotated, cropped, and reduced to post here, is the first of two images today, both of which show the ridges but of a completely different nature. Both are located in Hellas Basin in Mars southern hemisphere.

This first picture was taken on September 4, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows a sinuous complex that resembles to a remarkable extent a set of river tributaries, but is instead a set of raised ridges rather than a canyon system.

Scientists have found more than 10,000 miles of such ridges in the northern hemisphere in Arabia Terra, the most extensive transition zone between the southern highlands and the northern lowlands, and have dubbed them fossilized rivers. From a 2016 press release:

The inverted channels are similar to those found elsewhere on Mars and Earth. They are made of sand and gravel deposited by a river and when the river becomes dry, the channels are left upstanding as the surrounding material erodes. On Earth, inverted channels often occur in dry, desert environments like Oman, Egypt, or Utah, where erosion rates are low – in most other environments, the channels are worn away before they can become inverted. “The networks of inverted channels in Arabia Terra are about 30m high and up to 1–2km wide, so we think they are probably the remains of giant rivers that flowed billions of years ago. Arabia Terra was essentially one massive flood plain bordering the highlands and lowlands of Mars. We think the rivers were active 3.9–3.7 billion years ago, but gradually dried up before being rapidly buried and protected for billions of years, potentially preserving any ancient biological material that might have been present,” added Joel Davis.

Nor are such features on Mars limited to Hellas and Arabia Terra. For a particularly spectacular feature in the cratered highlands see this 2019 post.

The origin of these sinuous ridges in Hellas might have a similar origin as these other fossilized rivers. At present the bottom of Hellas, the deepest basin on Mars, is a place with little signs of ice. In the past there is evidence that lakes once existed here, so we cannot rule out water as a cause.

At the same time, Hellas was formed by a gigantic impact. One cannot dismiss the possibility of a volcanic origin, impact melt left over from the heat of that crash.

Today’s second ridge complex in Hellas looks far different.
» Read more

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Jupiter’s southern jet streams

9:21 am

Jupiter's southern jet streams
Click for full image.

Cool image time! The photo to the right, rotated and reduced slightly to post here, shows the southern jet streams in Jupiter’s atmosphere. From the press release:

The storm known as the Great Red Spot is also visible on the horizon, nearly rotated out of view as Juno sped away from Jupiter at about 30 miles per second (48 kilometers per second), which is more than 100,000 mph (160,900 kilometers per hour).

Citizen scientist Tanya Oleksuik created this color-enhanced image using data from the JunoCam camera. The original image was taken on Dec. 30, 2020 as the Juno spacecraft performed its 31st close flyby of Jupiter. At the time, the spacecraft was about 31,000 miles (about 50,000 kilometers) from the planet’s cloud tops, at a latitude of about 50 degrees South.

According to data obtained by Juno, these bands of storms extend about 1,800 miles into Jupiter’s interior, much deeper than expected.

The Great Red Spot is at about 22 degrees south latitude, so this tells us that this picture covers Jupiter’s southern hemisphere from about the equator down to about 80 degrees.

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Turkey to do lunar mission, send astronaut into space

8:59 am

The new colonial movement: Turkey’s leader, Tayyip Erdogan, announced yesterday a new space exploration initiative that will include sending an unmanned probe to the Moon as well as flying an astronaut into space.

“The first rough landing will be made on the moon with our national and authentic hybrid rocket that shall be launched into orbit in the end of 2023 through international cooperation,” Erdogan said, detailing a two-phase mission. Erdogan did not elaborate further on the cooperation. Last month, Erdogan spoke to Tesla and SpaceX boss Elon Musk on possible cooperation in space technologies with Turkish companies.

Speaking in an event in Ankara, Erdogan announced a programme with 10 strategic goals including sending a Turkish citizen to a scientific mission in space.

The manned mission will not be flown by Turkey, but will be purchased from someone else, either Russia or SpaceX or Boeing maybe even China.

The timing of this announcement, the same day the UAE’s Al-Amal probe entered Mars’ orbit, suggests it was prompted by that success, and is an example of keeping up with the Joneses. Whether there is any reality to these proposals however remains to be seen.

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China’s Tienwen-1 enters Mars orbit

8:42 am

The new colonial movement: China’s Tienwen-1, carrying an as-yet-unnamed lander/rover, successfully inserted itself into orbit around Mars early today.

With a successful Mars Orbit Insertion, the craft has entered a highly eccentric, equatorial capture orbit of the planet, and controllers will now spend two months undertaking initial activations and checkouts in Martian orbit for the primary science mission while altering the craft’s orbit from equatorial to polar.

In April 2021, the lander, with the rover inside, will detach from the orbiter and prepare for Entry, Descent, and Landing. Prior to launch, 23 April 2021 was given as the target landing date.

The landing location is within Utopia Planitia and will — if the orbit insertion burn is completed successfully — utilize a combination of aerobraking, parachute descent, retrorocket firing, and airbag deployments to achieve a soft touchdown on the Martian surface. After landing, the rover will be deployed — ideally on the same day — to begin a planned 90 Sol (Martian day) mission to categorize the local environment.

The suspected landing site in Utopia Planitia is at about 25 degrees north latitude. Though it is in the northern lowland plains, this latitude places it south of the latitudes (greater than 30) that scientists now believe ample ice likely exists underground but accessible. The lander/rover carries radar equipment capable of detecting evidence of underground ice, and will look nonetheless. If it finds any, this will be a significant discovery.

Two down, one to go. Next week, on February 18th, the American rover Perseverance will attempt its landing in Jezero crater.

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Another “What the heck?!” image on Mars

2:53 pm

A
Click for full image.

Today’s cool image, taken on September 2, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and cropped and reduced to post here, is one that I will make very little attempt to explain. It falls into a category I call “What the heck?!” The uncaptioned website labels this “Ringed Ridges in Kasei Valles”, which merely describes what we see.

This isn’t an impact crater. The rings don’t fit any morphology I’ve ever seen for such features.

Could we be looking at some type of glacial feature? The latitude, 29 degrees north, makes this unlikely but possible. Even so, it sure doesn’t look like it. The ripples in the center and between the ridges are sand dunes, not glacial features.

Might this be a volcanic vent, with the concentric ridges marking multiple eruptions? Maybe, but if so I’ve never seen any volcanic vent or caldera that looked quite like this.

The overview map below gives some context, but hardly explains anything.
» Read more

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Sunspot update: January activity returns to expected levels

12:18 pm

Though I am a bit late this month, it is once again time provide my monthly update of the Sun’s on-going sunspot cycle. Below is NOAA’s February 1, 2021 monthly graph, showing the Sun’s monthly sunspot activity. I have, as I do each month, annotated it to show the previous solar cycle predictions.

After two months of relatively high activity, activity that was very high so early in the ramp up to solar maximum, the number of sunspots in January dropped down to closely match the predicted value. It was still higher, but not by much.

» Read more

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