Tag: science

Surprisingly low number of observation proposals from astronomers for Webb telescope

4:03 pm

In preparation for the launch of the James Webb Space Telescope in ’21, the Space Telescope Science Institute (STScI) that will operate it has begun accepting observation proposals from astronomers, and has apparently discovered that the number of proposals, dubbed the subscription rate, is surprisingly low.

The stats of the James Webb space telescope cycle 1 proposal round came in the other day. In summary: an over subscription rate of 1:4. A little less even.

There was immediate spin how the stats were a good thing. Enthusiasm from around the globe! So many investigators! But that does not change that the 1:4 oversubscription is a disappointment. If I were part of the project, this would and should worry me.

If they got exactly the right number of proposals to precisely use all of the telescope’s observation time, the subscription rate would be 1. An oversubscription rate of 1.4 seems good, but in truth it is tiny compared to Hubble and other space telescopes, and horrible considering the cost of Webb (almost $10 billion, 20x what it was originally budgeted).

The author at the link provides some technical reasons for the low interest, some of which are the fault of the Webb management team (such as a very complicated proposal process) and some that are beyond their control (the Wuhan panic). He also provides suggestions that might help.

Either way, the relatively low interest I think is rooted in Webb’s initial genesis. It was pushed by the cosmological community and its design thus optimized for studying the early universe. Other astronomical fields were pushed aside or given a lower priority so that the telescope does not serve them as well.

The result is that a lot of astronomers have been finding other more appropriate and already functioning telescopes to do their work, bypassing Webb entirely. They are probably also bypassing Webb because it seems foolish to spend the inordinate amount of time putting together a proposal for a telescope a decade behind schedule that carries an enormous risk of failure once it is launched.

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Puerto Rican government commits $8 million to rebuild Arecibo

8:16 am

The government of Puerto Rico earlier this week announced that it has allocated $8 million to rebuild the Arecibo Observatory.

Via an executive order, Gov. Wanda Vazquez made reconstruction of the observatory public policy. In a ceremony at La Fortaleza, the seat of the island’s government, Vazquez said that the Puerto Rican government believes that the telescope’s collapse provides a great opportunity to redesign it, taking into account the lessons learned and recommendations from the scientific community so that it remains relevant for decades to come.

…Vazquez said that she and her administration want the scope to once again become a world class center and the $8 million being allocated for reconstruction includes funds to repair the environmental damage caused by the collapse, something that has already begun under the supervision of the National Science Foundation (NSF).

We shall see what happens. $8 million is not really enough to rebuild Arecibo. And the NSF has been trying to unload it from its budgetary responsibility for almost a decade. I would be shocked if that agency now suddenly decided to fund its reconstruction.

Only if Congress gets involved will this likely change, and that wouldn’t surprise me, considering how nonchalant our present Congress is about spending money that doesn’t exist.

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Summer at the Martian south pole

1:34 pm

Overview of the Martian south pole

Today we have two cool images, both giving us a tiny glimpse at what it is like in the middle of summer on the fringes of Mars’ south pole ice cap. Their location is indicated by the blue crosses on the overview map on the right.

To review, the south pole on Mars is, like its north pole, mostly made up of a permanent icecap of water. In the south, this icecap is mostly mixed with dust and debris in the area outlined in black and dubbed the layered deposits. On top of this is a smaller thick water ice cap, indicated by light blue, which is in turn topped by a thin cap of frozen carbon dioxide, or dry ice, indicated by white. During the winter the entire pole, down to 60 degrees latitude also gets covered by a temporary mantle of dry ice, that sublimates away each spring.

Now for our cool images!
» Read more

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The seas of Titan, deep and alien

11:29 am

Radar track through the estuaries of Titan's large sea, Kraken Mare

The uncertainty of science: In a new paper scientists have taken the radar data from the more than 120 fly-bys by Cassini of Titan to map out the estimated depths for several of Titan’s seas, using that data to also better constrain the make-up of those seas. From their abstract:

Our analysis reveals that the seafloor at the center of Moray Sinus—an estuary located at the northern end of Kraken Mare, is up to 85 m deep. The radar waves are absorbed to an extent such that the liquid composition is compatible with 70% methane, 16% nitrogen, and 14% ethane (assuming ideal mixing). The analysis of the altimetry data in the main body of Kraken Mare showed no evidence for signal returns from the sea floor, suggesting the liquid is either too deep or too absorptive for Cassini’s radio waves to penetrate. However, if the liquid in the main body of Kraken Mare is similar in composition to Moray Sinus, as one would expect, then its depth exceeds 100 m.

The image above, cropped and reduced to post here, is figure two from the paper. » Read more

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Published results from Curiosity as it traversed Vera Rubin Ridge

9:34 am

The science results from American Mars rover Curiosity during its traverse of Vera Rubin Ridge at the base of Mount Sharp in Gale Crater have now been released to the public.

This link takes you to the overview paper, available online for free. The abstract notes the key finding, which confirms previously released research:

We conclude Vera Rubin ridge formed because groundwater recrystallized and hardened the rocks that now make up the ridge. Wind subsequently sculpted and eroded Mount Sharp, leaving the harder ridge rocks standing because they resisted erosion compared with surrounding rocks. The implication of these results is that liquid water was present at Mount Sharp for a very long time, not only when the crater held a lake but also much later, likely as groundwater.

The fundamental geological mystery of Mars remains. The evidence strongly says that liquid water must have existed for long periods on the surface of Mars. At the same time, other evidence strongly says that the climate and atmosphere of Mars has never been warm enough or thick enough to allow for liquid water on the planet’s surface.

So far, no global model proposed by any theorist that allows liquid water in the past on Mars has been accepted with any enthusiasm by the planetary community. While possible, the models carry too many assumptions and are based on what is presently far too limited data. We simply do not yet know enough about Mars and its past history to explain this conundrum.

The paper also outlines a number of models for allowing liquid water in the localized area of Gale Crater alone. As with the global models, none fits all the facts, or is entirely satisfactory for explaining the data.

Regardless, the results from Vera Rubin Ridge confirm once again that enough liquid water once did exist on Mars to have allowed it to be habitable for life, even if we have so far found no evidence of any past life.

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First look at Ryugu samples

8:55 am

Japanese scientists have taken their first look at the Ryugu sample material brought back by Hayabusa-2 and found they resemble charcoal.

The samples Japanese space officials described Thursday are as big as 1 centimeter (0.4 inch) and rock hard, not breaking when picked up or poured into another container. Smaller black, sandy granules the spacecraft collected and returned separately were described last week.

…The sandy granules the Japan Aerospace Exploration Agency described last week were from the spacecraft’s first touchdown in April 2019.

The larger fragments were from the compartment allocated for the second touchdown on Ryugu, said Tomohiro Usui, space materials scientist. To get the second set of samples in July last year, Hayabusa2 dropped an impactor to blast below the asteroid’s surface, collecting material from the crafter so it would be unaffected by space radiation and other environmental factors.

Usui said the size differences suggest different hardness of the bedrock on the asteroid. “One possibility is that the place of the second touchdown was a hard bedrock and larger particles broke and entered the compartment.”

The analysis of these samples has only just begun. Dating them is likely next, and that will probably reveal some startling results.

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A Martian polliwog

3:32 pm

Three-mile-wide crater with exit breach
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on September 30, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

It shows one half of what scientists have dubbed a pollywog crater, in which there is a single breach in the crater wall, aligned with the low point in the crater’s floor. Such craters suggest that they were once water- or ice-filled, and that they drained out through the breach either quickly in a single event or slowly over multiple events.

The second image below was taken by the wide angle context camera on MRO, and not only shows this entire crater, but several other adjacent craters, all of which show evidence of glacial fill in their interiors. The latitude here is 34 degrees south, placing these craters within the mid-latitude bands where such glacial features have been found by scientists in great numbers.
» Read more

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A Mars mosaic from Curiosity using its close-up camera

9:36 am

During the three-plus months in the summer when Curiosity stayed at one location for its most recent drilling campaign, the science team used its ChemCam Remote Micro-Imager camera (RMI), originally designed to take very close-up photos, to create a 216 photo mosaic of the long distance horizon. They have now released that mosaic, which you can see as a video at the link. The mosaic itself is a very long strip, which is best viewed up close and scrolling across it, as the video does. As the scientists note,

During Curiosity’s first year on Mars, it was recognized that, thanks to its powerful optics, RMI could also go from a microscope to a telescope and play a significant role as a long-distance reconnaissance tool. It gives a typical circular “spyglass” black and white picture of a small region. So RMI complements other cameras quite nicely, thanks to its very long focal length. When stitched together, RMI mosaics reveal details of the landscape several kilometers from the rover, and provides pictures that are very complementary to orbital observations, giving a more human-like, ground-based perspective.

From July to October of 2020, Curiosity stayed parked at the same place to perform various rock sampling analyses. This rare opportunity of staying at the same location for a long time was used by the team to target very distant areas of interest, building an ever-growing RMI mosaic between September 9 and October 23 (sols 2878 and 2921) that eventually became 216 overlapping images. When stitched into a 46947×7260 pixel panorama, it covers over 50 degrees of azimuth along the horizon, from the bottom layers of “Mount Sharp” on the right to the edge of “Vera Rubin Ridge” on the left.

The camera’s resolution is so good that it was able in the mosaic to resolve large boulders on the crater wall of Gale Crater almost 37 miles away.

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The conjunction of Jupiter and Saturn, as seen from the Moon

9:21 am

Jupiter and Saturn as seen by LRO
Click for full image.

With Jupiter and Saturn closer to each other in the sky than they have been in about 800 years, the science team for Lunar Reconnaissance Orbiter (LRO) decided to aim that lunar orbiter at the two gas giants to get a picture.

The photo to the right, cropped and expanded to post here, was also enhanced by the science team to brighten Saturn so that it would match Jupiter. As they note at the link,

[LRO] captured this view just a few hours after the point of closest separation (0.1°) between the two giant planets. With the sharp focus of the NAC [camera], you can see that the two planets are actually separated by about 10 Jupiter diameters

Both planets however look fuzzy in the image, probably because the camera was not designed to obtain sharp images from this distance. Nonetheless, this is a very cool photo.

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Samples from space!

9:16 am

Scientists from both the Japanese Hayabusa-2 mission to the asteroid Ryugu and the Chinese Chang’e-5 mission to the Moon announced yesterday the total amount of material they successfully recovered.

The numbers appear to diminish the Japanese success, but that is a mistake. Getting anything back from a rubble-pile asteroid that had never been touched before and is much farther away from Earth than the Moon was a very great achievement. The 5.4 grams is also more than fifty times the minimum amount they had hoped for.

This is also not to diminish the Chinese achievement, They not only returned almost four pounds, some of that material also came from a core sample. They thus got material both from the surface and the interior of the Moon, no small feat from an unmanned robot craft.

Scientists from both nations will now begin studying their samples. Both have said that some samples will be made available to scientists from other countries, though in the case of China it will be tricky for any American scientist to partner with China in this research, since it is by federal law illegal for them to do so.

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Mysterious signal detected possibly coming from Proxima Centauri

9:05 am

The uncertainty of science: Breakthough Listen, the project funded to the tune of $100 million by billionaire Yuri Milner with the goal of listening for alien radio signals, in 2019 detected a single radio tone that appeared to be coming from the nearest star, Proxima Centauri.

A team had been using the Parkes radio telescope in Australia to study Proxima Centauri for signs of flares coming from the red dwarf star, in part to understand how such flares might affect Proxima’s planets. The system hosts at least two worlds. The first, dubbed Proxima b upon its discovery in 2016, is about 1.2 times the size of Earth and in an 11-day orbit. Proxima b resides in the star’s “habitable zone,” a hazily defined sector in which liquid water could exist upon a rocky planet’s surface—provided, that is, Proxima Centauri’s intense stellar flares have not sputtered away a world’s atmosphere. Another planet, the roughly seven-Earth-mass Proxima c, was discovered in 2019 in a frigid 5.2-year orbit.

Using Parkes, the astronomers had observed the star for 26 hours as part of their stellar-flare study, but, as is routine within the Breakthrough Listen project, they also flagged the resulting data for a later look to seek out any candidate SETI signals. The task fell to a young intern in Siemion’s SETI program at Berkeley, Shane Smith, who is also a teaching assistant at Hillsdale College in Michigan. Smith began sifting through the data in June of this year, but it was not until late October that he stumbled upon the curious narrowband emission, needle-sharp at 982.002 megahertz, hidden in plain view in the Proxima Centauri observations. From there, things happened fast—with good reason. “It’s the most exciting signal that we’ve found in the Breakthrough Listen project, because we haven’t had a signal jump through this many of our filters before,” says Sofia Sheikh from Penn State University, who helmed the subsequent analysis of the signal for Breakthrough Listen and is the lead author on an upcoming paper detailing that work, which will be published in early 2021. Soon, the team began calling the signal by a more formal name: BLC1, for “Breakthrough Listen Candidate 1.”

The data so far does not suggest this signal was produced by an alien technology. Instead, it likely is a spurious signal from some natural or human source, picked up by accident, as was the SETI “Wow” signal that for years puzzled astronomers until they traced it to a comet.

However, as they do not yet have an explanation, it is a mystery of some importance.

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Subaru Telescope photographs Hayabusa-2’s next target asteroid

2:09 pm

In order to better constrain its orbit, the Subaru Telescope in Hawaii has obtained new photographs of Hayabusa-2’s next target asteroid, 100-foot-wide 1998 KY26.

This asteroid is predicted to approach to within 0.47 AU of Earth in mid to late December 2020, giving us a rare opportunity that comes only once every three and a half years. However, the diameter of 1998 KY26 is estimated to be no more than 30 meters, and thus its brightness is so dim that ground-based observations of the asteroid are difficult without a very large telescope.

The observations with the Subaru Telescope were conducted upon the request of the Institute for Space and Astronautical Science (ISAS), JAXA. And as a result, 1998 KY26 was photographed in the direction of the constellation Gemini as a 25.4-magnitude point of light with a measurement uncertainty of 0.7 mag. The positional data collected during these observations will be used to improve the accuracy of the orbital elements of the asteroid. Similar observations were conducted with the Very Large Telescope (VLT) of the European Southern Observatory (ESO).

If all goes right Hayabusa-2 will rendezvous with 1998 KY26 in the summer of 2031.

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