Gil Levin passes away

Gil Levin, a instrument project scientist for one of the science experiments on the Mars Viking landers in the 1970s, has passed away at 97.

Levin deserves special mention because he believed for years that his experiment, called “labeled release,” had possibly found evidence of life.

Dr. Levin’s experiment employed a nine-foot arm to scoop Martian soil into a container, where it was treated with a solution containing radioactive carbon nutrients. Monitors detected the release of radioactive gas, which Dr. Levin interpreted as evidence of metabolism.

“Gil, that’s life,” Straat said when they saw the results.

The findings held true for both Viking 1 and Viking 2, which took samples from different regions of the planet. Other experiments aboard the Viking, however, used different methods to conclude that Martian soil did not contain carbon, an element found in all living things.

Dr. Levin stood by his findings, but top NASA scientists disagreed, saying that the response he observed was the result of inorganic chemical responses, not biological processes. “Soon thereafter,” Dr. Levin told the Johns Hopkins University School of Engineering Magazine last year, “I gave a talk at the National Academy of Sciences saying we detected life, and there was an uproar. Attendees shouted invectives at me. They were ready to throw shrimp at me from the shrimp bowl. One former adviser said, ‘You’ve disgraced yourself, and you’ve disgraced science.’”

I met Levin once and interviewed him several times. With amazing grace and cheerfulness he always emphasized that his results needed to be confirmed, and there was certainly room for skepticism, but to reject them outright was not how the scientific method worked.

Levin however was never awarded another NASA project, essentially blackballed because of his 1970s claims, even though later research hinted at the possibility that he may have been right.

R.I.P. Gil Levin. Though the overall data we have gotten from Mars in the half century since still favors a non-life explanation for his experiment, the uncertainty remains quite large. He could have been right.

More important than his uncertain result, however, was his dedication to the proper scientific method, where you let the data speak for itself and never dismiss any possibility if that is what the data shows you.

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Curiosity’s wheels: a good news update

Curiosity's wheels
Click here and here for the original images.

For the past few weeks Curiosity has been traveling across some of the roughest terrain it has seen on Mars, since landing in Gale Crater in August 2012. The rover is now roving among the high cliffs and foothills at the very base of Mt Sharp, with the ground covered with rocks, boulders, plates of bedrock, and all sorts of protrusions.

On August 1st the rover team used its cameras to do another survey of the rover’s wheels to see how they fared during that journey. The two images to the right compare the same area on the same wheel after the most recent 16 sols of travel. This is the same wheel I have focused on since 2017. Overall, the damage in the most recent picture seems almost identical to the previous picture. In fact, if you compare today’s image with the annotated version of the 2017 photo, found here, you can see how little things have changed since then.

From this one wheel it appears that the wheels are continuing to hold up quite well. The Curiosity team of course needs to review all the images of all the wheels, but based on this one comparison, it looks like their long term strategies for mitigating damage to the wheels is working, even in the rough terrain the rover is presently traversing.

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Martian lava flooded crater?

lava flooded crater?
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A quick cool image! The photo to the right, rotated, cropped and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) more than a decade ago, on June 1, 2010. I post it now because it is today’s MRO picture of the day, and is definitely cool. The caption:

One of a few “scaly-looking” inselbergs within regional platy-ridged flows in Elysium Planitia. This inselberg has a broken and blocky appearance with some of the blocks being tilted. Could this be the remnant of a once extensive mantling deposit? An inselberg is an isolated hill or mountain rising abruptly from a plain.

The wider image by MRO’s context camera below, also rotated, cropped and reduced to post here, illustrates even more forcefully how isolated this circular set of blocks is.
» Read more

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Two flybys of Venus set by two spacecraft on August 9th and 10th

Two European planetary probes, one launched to study the inner solar enviroment and the second to study Mercury, are going to fly past Venus only 33 hours apart on August 9th and 10th.

Solar Orbiter, a partnership between ESA and NASA, will fly by Venus on 9 August with a closest approach of 7995 km at 04:42 UTC. Throughout its mission it makes repeated gravity assist flybys of Venus to get closer to the Sun, and to change its orbital inclination, boosting it out of the ecliptic plane, to get the best – and first – views of the Sun’s poles.

BepiColombo, a partnership between ESA and JAXA, will fly by Venus at 13:48 UTC on 10 August at an altitude of just 550 km. BepiColombo is on its way to the mysterious innermost planet of the solar system, Mercury. It needs flybys of Earth, Venus and Mercury itself, together with the spacecraft’s solar electric propulsion system, to help steer into Mercury orbit against the immense gravitational pull of the Sun.

The two spacecraft will zip past a different side of Venus. For a variety of reasons, the imagery gathered will not of high resolution, though both spacecraft will gather data that will eventually be correlated with similar data being gathered by Japan’s Akatsuki probe, in orbit around Venus since 2015.

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The sublimating surface of Mars’ northern plains?

Sublimating patches on Mars?
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Cool image time! The photograph to the right, cropped and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter on May 27, 2021. A sample image, likely taken not as part of any specific scientist’s research but by the camera team in order to maintain the camera’s temperature, shows an area of the Martian northern plains that appears filled with rough scattered depressions, possibly caused by sublimation of buried ice.

The location, at 54 degrees north latitude, is far enough north to easily have a lot of buried ice. It is also only about 40 miles to the east of Milankovič Crater, where scientists have found many scarps that appear to have exposed layers of ice in their cliff faces.

However, the location has other components that must raise questions about this sublimating ice hypothesis.
» Read more

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Sunspot update: Another month of greater activity than predicted

NOAA this past weekend released an update of its monthly sunspot cycle graph, showing the Sun’s sunspot activity for the past month. That graph is below, annotated to show the previous solar cycle predictions and thus provide context.

In July the Sun’s hot streak of sunspot activity continued. The number of sunspots on its visible hemisphere continued to exceed the prediction of NOAA’s solar science panel, with the numbers in July easily topping June’s numbers. Only at the very end of July was there a streak of five blank days, the first time the Sun has been blank of sunspots since May 6th, a stretch of activity not seen for years, since the last solar maximum was ramping down to solar minimum in ’16-’17.

The political consequences of this continuing high activity could be quite profound.
» Read more

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Zhurong continues south, inspecting dunes

Zhurong's travels as of July 31, 2021

The Chinese science team for their Zhurong Mars rover released new images yesterday, including a map showing the rover’s present position.

The new images and location has confirmed that the white streaks seen in orbital pictures are small dunes of sand blown by the thin Martian wind.

The map to the right, created using their map but annotated and providing a wider context, shows their present location relative to the lander and surrounding terrain. So far the rover has traveled about 1,900 feet, about 1,000 feet per month. Since it seems to be operating as planned, I expect China will extend the mission once it completes its nominal three-month tour in about two weeks.

At that travel pace there is much of interest that is within the rover’s range. I expect they are heading south partly because this brings them closer to their original landing site, which is an area they probably studied at length before landing. Whether they head to the largest crater, visible only partly on the image’s south edge, remains unclear.

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Apollo: When Americans last did some real exploring

The journey of Apollo 15 on the Moon
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Today is the fiftieth anniversary of the landing of Apollo 15 on the Moon. To commemorate that event the science team for Lunar Reconnaissance Orbiter (LRO) today published some orbital images that capture the astronauts’ travels while on the Moon. The picture to the right, reduced to post here, outlines in oblique view their various excusions to the edge of Hadley Rille and the foot of a mountain dubbed Hadley Delta. As they note,

While Apollo 15 was the fourth mission to land a crew successfully on the lunar surface, it still pioneered many new technologies and had many firsts.

Some of the technologies developed for Apollo 15 included new suits, which were more flexible and had longer life support capabilities, as well as the Lunar Roving Vehicle (LRV), a rover capable of speeds up to 15 km / hour. With these advancements, astronauts Commander David (Dave) Scott and Lunar Module Pilot James (Jim) Irwin were able to travel more than eight times the distance traveled during the previous mission, for a total of over 25 km.

All told, astronauts Dave Scott and Jim Irwin spent more than 18 hours exploring the lunar surface on three scouting trips, covering 15.5 miles. During all those excursions their only protection from the harsh lunar environment was that thin spacesuit. In addition, if their rover broke down a walk back to the lunar module would become a race against suffocation.

And even then, they still had to get that lunar module off the ground, rendezvous and dock with the Apollo 15 command module, and then get that module back to Earth safely.
» Read more

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Apollo 11 lunar ascent stage might still be in orbit around the Moon

New data about the Moon’s interior and gravitational field suggest that the Apollo 11 lunar ascent stage, the part of the LM that carried the astronauts back from the Moon, might still be in orbit around the Moon, rather than have crashed into its surface as long assumed.

Using the GRAIL gravity model and the General Mission Analysis Tool (GMAT) simulator, Meador expected to find the LM’s orbit destabilizing very quickly. What he found – and was verified by a third party using different methods – was that the Ascent Stage had a feedback mechanism that caused the orbit to stabilize itself over a period of every 24 days. When he ran the simulation forward, the orbit remained stable until the present day.

The upshot of this is that the Ascent Stage may still be in orbit now and could be observed when it is in the right position in relation to the Earth and the Sun. However, Meador emphasizes that the LM was never intended to be very robust. Designed to operate for only about 10 days, it was also filled with batteries and fuel tanks, which could have exploded years ago, either destroying the craft or sending it off on a new trajectory.

If the stage is in lunar orbit, than it probably is one the most valuable and quickly reachable artifacts from one of space’s most historic missions. While the Apollo artifacts left on the Moon should be left where they are, this piece could be recaptured and returned to Earth for both study and exhibition.

In fact, if it is still in orbit it should be recovered, to preserve it.

This data also suggests that other Apollo ascent stages as well as other past lunar orbiters might also still be in lunar orbit, and should be located.

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The view of Jezero Crater, from both Ingenuity and Perseverance

The view from Ingenuity during 10th flight
Click for full image.

Cool image time! Today the Perseverance science team released the 200 images that Ingeniuty took during its 10th flight on July 24, 2021.

The photo to the right was taken about 25 seconds before the helicopter landed, and looks to the southwest. In the foreground can be seen the ridge of rocks and pebbles that the scientists sent Ingeniuty to photograph. In the distance can be seen the rim of Jezero Crater, about 7.5 miles away, with some rounded hills that sit in the crater floor about 5.5 miles away.

The white box indicates the area covered by two high resolution images taken by Perseverance on July 28th that I have combined into the panorama below.
» Read more

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Atomic oxygen in Mars’ atmosphere, as seen by Al-Amal

Oxygen distribution on Mars

The UAE’s Al-Amal Mars orbiter on July 19, 2021 released a new spectroscopic image, showing the global distribution of atomic oxygen in the Martian upper atmosphere.

The Emirates Ultraviolet Spectrometer (EMUS) mapped the distribution of atomic oxygen in the planet’s upper atmosphere, showing a dense patch emerging from the nightside into the new day.

The photo to the right, cropped and reduced to post here, shows this.

Over the next two years, covering one single Martian year, Al-Amal will monitor the distribution of this oxygen to see how it fluctuations from season to season, as well as from day to day. Gather this information will help the theorists untangle the past atmospheric history of Mars.

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For the first time astronomers measure the rotation of exoplanets

The uncertainty of science: Using the Keck Telescope in Hawaii astronomers for the first time have measured the rotation of several exoplanets orbiting the star HR8799, about 129 light years away.

Using the state-of-the-art Keck Planet Imager and Characterizer (KPIC) on the Keck II telescope atop Hawaiʻi Island’s Maunakea, astronomers found that the minimum rotation speeds of HR 8799 planets d and e clocked in at 10.1 km/s and 15 km/s, respectively. This translates to a length of day that could be as short as three hours or could be up to 24 hours such as on Earth depending on the axial tilts of the HR 8799 planets, which are currently undetermined. For context, one day on Jupiter lasts nearly 10 hours; its rotation speed is about 12.7 km/s.

As for the other two planets, the team was able to constrain the spin of HR 8799 c to an upper limit of less than 14 km/s; planet b’s rotation measurement was inconclusive.

These results are somewhat uncertain, as are any conclusions theorists try to draw from them. Even if confirmed, the sample is so small it doesn’t tell us anything yet about overall trends in planet formation or the expected spin rate of planets as they form.

Nonetheless, the detection appears valid and thus a scientific triumph. Astronomers have been telling me for years that figuring out ways to find out more about exoplanets is going to become the next hot subject in astronomy. This result illustrates this.

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