Tag: science

Landslides on Ceres

9:31 am

Landslides on rim of Occator Crater

Cool image time! With Dawn completing its descent into its final low orbit only about 30 miles above the surface of Ceres, it is beginning to take some very spectacular images. Above is a cropped section from a full image taken on June 9th of the rim of Occator Crater from an altitude of 27 miles. It shows evidence of landslides on the crater’s rim, as well as at least two bright patches. If you click on it you can see the entire picture.

Crater on Ceres

Nor is this the only cool image released As Dawn descended to its new orbit, it took one very cool oblique image of the planet’s horizon. On the right I have cropped a small section out of one such image, taken on May 30th from an altitude of 280 miles. If you click on it you can see the full image, showing numerous other small craters all around it, to the horizon.

Note the bright streaks on the crater walls, suggestive of more landslides as well as seepage of the thought-to-exist brine from below the surface.

For the next year or so, as Dawn winds down its mission, expect a lot more very intriguing pictures of Ceres. I am especially eager to see close-ups of the bright spots at the center of Occator Crater.

Leave a comment

New analysis suggests Ceres has more organic molecules than previously estimated

12:11 pm

The uncertainty of science: A new analysis of data from Dawn now suggests that the surface of Ceres has a greater percentage of organic molecules than previously estimated.

To get an initial idea of how abundant those compounds might be, the original research team compared the VIR data from Ceres with laboratory reflectance spectra of organic material formed on Earth. Based on that standard, the researchers concluded that between six and 10 percent of the spectral signature they detected on Ceres could be explained by organic matter.

But for this new research, Kaplan and her colleagues wanted to re-examine those data using a different standard. Instead of relying on Earth rocks to interpret the data, the team turned to an extraterrestrial source: meteorites. Some meteorites — chunks of carbonaceous chondrite that have fallen to Earth after being ejected from primitive asteroids — have been shown to contain organic material that’s slightly different from what’s commonly found on our own planet. And Kaplan’s work shows that the spectral reflectance of the extraterrestrial organics is distinct from that of terrestrial counterparts.

“What we find is that if we model the Ceres data using extraterrestrial organics, which may be a more appropriate analog than those found on Earth, then we need a lot more organic matter on Ceres to explain the strength of the spectral absorption that we see there,” Kaplan said. “We estimate that as much as 40 to 50 percent of the spectral signal we see on Ceres is explained by organics. That’s a huge difference compared to the six to 10 percent previously reported based on terrestrial organic compounds.”

Please note: Both estimates depend on assumptions that could easily be wrong. Ceres might have less organics, or more, than either estimate. Or somewhere in the middle. These estimates are merely educated guesses.

And remember, organic molecules does not mean life. It only means the molecules use carbon as a component.

Leave a comment

Contact with Opportunity lost

9:33 am

The Opportunity science team has lost contact with Opportunity as it automatically shuts down operations to survive low battery power due to the dust storm.

This does not necessarily mean the rover is dead. Depending on how long this period of low power lasts, the rover could return to life once the dust storm passes. Or not. We can only wait and see.

A press conference today on the dust storm and Opportunity’s status begins at 1:30 Eastern time today.

8 comments

The two candidate landing sites for ExoMars2020

12:27 pm

The June release of new images from Mars Reconnaissance Orbiter (MRO) included three images of the two candidate landing sites for Europe’s 2020 ExoMars rover mission. All three images provide us as hint at what that rover might see when it arrives a few years from now.

ExoMars 2020 landing sites

The two candidate sites are locations on Mars dubbed Mawrth Vallis and Oxia Palas. The map to the right shows their general location to the east of Mars’s giant volcanoes and giant canyon Valles Marineris. The red splotches indicate the large number of images taken by MRO of these locations, partly to help the ExoMars science team choose which site to pick and partly to study the geology in these Martian locations. As you can see, both candidate sites are in the transition zone between the northern low plains and the southern highlands.

At first glance Mawrth Vallis seems the more spectacular site. Mawrth (Welsh for Mars) is one of the gigantic drainage canyons near Valles Marineris. Though tiny in comparison to Valles Marineris, on Earth it would easily rival the Grand Canyon in size, and in fact is slightly longer (400 miles versus 300 miles). Unlike the Grand Canyon, however, Mawrth Vallis doesn’t appear to have a distinct or obvious rim. This video, produced by the European Space Agency using images from its Mars Express orbiter, gives a sense of the canyon’s terrain as it flies upstream from the northern lowlands to the canyon’s high point in the southern highlands. The highlands on either side of the canyon more resemble the broken geology of Mars’s chaos regions that are found scattered about in this transition zone than the flat generally level Kaibab plateau that surrounds the Grand Canyon.

Mawrth Vallis

The image on the right is a tiny crop from the most recently released MRO image. The full image shows a strip of the upper plateau south of canyon and near its inlet from the southern highlands. This crop reveals a surface that is a wild mixture of colors and complex geology. In fact, in a 2017 MRO image release showing a different place in Mawrth Vallis, the canyon was dubbed a “painted desert.” To quote that release:

The clay-rich terrain surrounding Mawrth Vallis is one of the most scenic regions of Mars, a future interplanetary park. …The origin of these altered layers is the subject of continued debates, perhaps to be resolved by a future rover on the surface. We do know that these layers are very ancient, dating back to a time when the environment of Mars was wetter and more habitable, if there were any inhabitants.

Other MRO images of Mawrth Vallis here and here emphasize this description.

As for Oxia Palas, the other candidate landing site for ExoMars 2020, in the June MRO image release there were two images.
» Read more

Leave a comment

The mysterious dust surrounding Tabby’s Star

8:44 am

New studies of Tabby’s Star suggest that the dust clouds that cause it to fluctuate in brightness in apparently random ways are unusual and baffling in their own right.

[I]t appears that the dimming of Tabby’s star comes not from large objects such as swarms of asteroids, comets, or alien solar collectors, but from drifting bands of dust particles. But like any good mystery, it’s not quite that simple.

Each of the four dimming events observed in 2017 affected red and blue light differently, suggesting that they involved dust particles of different sizes. And the long-term brightness changes appear to be associated with much larger grains. “So the dust cloud is extremely complex,” Bodman says. “Each dip is a different kind of dust … What we’re seeing is different parts of the [dust] cloud as they pass in front of the star.”

A first guess, probably wrong, is that the four dimming events were caused by dust streams orbiting the star at different distances, each a different patchy ring around the star made up of slightly different materials.

And if you accept my guess as right, I also have bridge in Brooklyn I want to sell you. Real cheap too!

Leave a comment

China cracks down on corrupt science

8:38 am

The Chinese government has instituted new policies aimed at shutting down corrupt practices in journal peer review and funding that have previously encouraged scientific misconduct.

The country’s most powerful bodies, the Chinese Communist Party and the State Council, introduced a raft of reforms on 30 May aimed at improving integrity across the research spectrum, from funding and job applications to peer-review and publications.

Under the new policy, the Ministry of Science and Technology (MOST) will be responsible for managing investigations and ruling on cases of scientific misconduct, a role previously performed by individual institutions. And for the first time, misconduct cases will be logged in a national database that is currently being designed by MOST.

Inclusion in the list could disqualify researchers from future funding or research positions, and might also affect their ability to get jobs outside academia. The Chinese Academy of Social Sciences will oversee the same process for social scientists. The policy also states that MOST will establish a blacklist of ‘poor quality’ scientific journals, including domestic and international titles. Scientists who publish in these journals will receive a warning, and those papers will not be considered in assessments for promotions, jobs and grants. A couple of such blacklists already exist, but rarely are they run formally by a government agency.

In recent years China has been the source of many examples of blatant scientific misconduct, from faking data in papers to getting them peer reviewed by non-existent reviewers. This policy change is aimed at stopping this misconduct, and is likely happening because much of China’s leadership comes from its space industry, which requires honesty in its work or the rockets will crash.

At the same time, the policy gives the government great power over all scientific work, and we all know what happens eventually when you give the government great power. While the goals here are laudable, and will likely in the near future produce positive results, the long term consequences will likely end up stifling independent research.

Leave a comment

More Earthlike exoplanets!

9:13 am

Astronomers using data from Kepler have discovered two stars, both with multiple orbiting Earth-sized planets. One has three planets all almost exactly the mass of Earth.

The first exoplanetary system is located in the star K2-239, characterized by these researchers as a red dwarf type M3V from observations made with the Gran Telescopio Canarias (GTC), at the Roque de los Muchachos Observatory (Garafía, La Palma). It is located in the constellation of the Sextant at 50 parsecs from the Sun (at about 160 light years). It has a compact system of at least three rocky planets of similar size to the Earth (1.1, 1.0 and 1.1 Earth radii) that orbit the star every 5.2, 7.8 and 10.1 days, respectively.

The other red dwarf star called K2-240 has two super-Earth-like planets about twice the size of our planet. Although the atmospheric temperature of red dwarf stars, around which these planets revolve, is 3,450 and 3,800 K respectively, almost half the temperature of our Sun, these researchers estimate that all planets discovered will have temperatures superficial tens of degrees higher than those of the planet Earth due to the strong radiation they receive in these close orbits to their stars.

Knowing more about the surface environments of these very Earthlike exoplanets, as hostile as they might be to life, would teach us a great deal about our own planet and its birth and evolution.

5 comments

Curiosity finds methane fluctuates seasonally in Gale Crater

9:05 am

Seasonal methane on Mars

In its second significant science release yesterday (the first relating to the discovery of organics), the Curiosity science team revealed that they have found over almost three Martian years the amount of methane in the atmosphere appears to fluctuate seasonally. The graph on the right illustrates this change.

[The data] show methane rises from just above 0.2ppb in the northern hemisphere winter to a fraction over 0.6ppb in the summer. The team’s best explanation is that methane is seeping up from underground, perhaps from stored ices, and is then being released when surface soils are warmed.

The team cannot positively identify the origin of the methane, but the researchers think they can close down one particular mechanism for its production. This involves sunlight breaking up carbon-rich (organic) molecules that have fallen to the planet’s surface in meteorites.

The variation in ultraviolet light over the course of the seasons is not big enough to drive the scale of the change seen in the methane concentration, says Dr Webster. “We know the intensity of the Sun and this mechanism should produce only a 20% increase in methane during the summer, but we’re seeing it increase by a factor of three,” he explained.

The change could be caused by either a chemical or a biological process. At this time there is no way to determine which.

18 comments

Germany to do partial gravity experiments using Zero-G airplane

8:53 am

In what might be the first human experiments in partial gravity, Germany has hired the Zero-G airplane for a series of flights testing how humans react in such conditions.

In the Partial G Campaign, the pilots fly three special parabolic shapes. So instead of zero-g or microgravity, one quarter, half and three quarters of Earth’s gravity will still be present. Passengers on board will therefore experience one quarter, half or three quarters of their own body weight – depending on the trajectory,” explains Stang.

The goal of these flights is to see what effect partial gravity has on human muscle control.

For humans to be able to move around and interact with their environment, they require finely tuned muscle movements, to walk around or ensure a secure footing, for instance. Under partial gravity, in particular, they must be able to effectively control their muscles via their neural pathways. If we are unable to do so, the risk of stumbling is dramatically increased. This applies to both humans on Earth and astronauts in space. However, partial gravity conditions appear to influence this neuromuscular control in challenging situations, increasing the astronaut’s risk of stumbling. Researchers at the University of Freiburg are investigating why this is so. The results are intended to reduce the risk to astronaut safety during missions to other planets, thereby resolving a fundamental safety issue in human physiological space exploration.

This is better than nothing, but it seems to me to be the least important thing to study in partial gravity. The Apollo astronauts clearly demonstrated that humans can adapt their muscle movements to partial gravity. What we must instead learn is whether partial gravity will eliminate bone loss, loss of cardio-vascular conditioning, spinal changes, balance problems, and the vision damage, all of which have been found to occur in weighlessness.

At the same time, it is probably impossible to study any of these latter issues during a short parabolic vomit comet flight. The Germans are doing what they can. Unfortunately, they might be the only ones doing anything in this area.

One comment

How an accelerometer works

6:01 pm

An evening pause: A little dense for non-engineers, but just clear enough to be educational for all.

Hat tip Edward Thelen.

As always, I am in need of suggestions for evening pauses. If you’ve seen something you think will fit, place a comment here, in this post, but don’t post a link to your suggestions. I will contact you so that you can send it to me direct and I can then schedule it.

Leave a comment

Curiosity finds evidence of complex carbon molecules

11:40 am

In a study released today, the Curiosity science team announced that earlier drill samples revealed evidence of complex organic carbon molecules, the possible remains of past life.

To unlock organic molecules from the samples, the oven baked them to temperatures of between 600°C and 860°C—the range where a known contaminant disappeared—and fed the resulting fumes to a mass spectrometer, which can identify molecules by weight. The team picked up a welter of closely related organic signals reflecting dozens or hundreds of types of small carbon molecules, probably short rings and strands called aromatics and aliphatics, respectively. Only a few of the organic molecules, sulfur-bearing carbon rings called thiophenes, were abundant enough to be detected directly, Eigenbrode says.

The mass patterns looked like those generated on Earth by kerogen, a goopy fossil fuel building block that is found in rocks such as oil shale—a result the team tested by baking and breaking organic molecules in identical instruments on Earth, at Goddard. Kerogen is sometimes found with sulfur, which helps preserve it across billions of years; the Curiosity scientists think the sulfur compounds in their samples also explain the longevity of the Mars compounds.

Earth’s kerogen was formed when geologic forces compressed the ancient remains of algae and similar critters. It’s impossible to say whether ancient life explains the martian organics, however. Carbon-rich meteorites contain kerogenlike compounds, and constantly rain down on Mars. Or reactions driven by Mars’s ancient volcanoes could have formed the compounds from primordial carbon dioxide. Monica Grady, a planetary scientist at The Open University in Milton Keynes, U.K., believes the compounds somehow formed on Mars because she thinks it’s highly unlikely that the rover dug into a site where an ancient meteorite fell. She also notes that the signal was found at the base of an ancient lake, a potential catchment for life’s remains. “I suspect it’s geological. I hope it’s biological,” she says.

It must be emphasized once again that they have not found evidence of past life. What they have found are the types of molecules that are often left behind by life, but can also form without the presence of life.

This result, from past drillholes in the Murray Formation, explains however why Curiosity headed back downhill to do its most recent drill test.

Curiosity has one last tool to help the team find out: nine small cups containing a solvent that frees organic compounds bonded in rock, eliminating the need to break them apart—and potentially destroy them—at high temperatures. In December 2016, rover scientists were finally prepared to use one of the cups, but just then the mechanism to extend the rover’s drill stopped working reliably. The rover began exploring an iron-rich ridge, leaving the mudstone behind. In April, after engineers found a way to fix the drill problem, the team made the rare call to go backward, driving back down the ridge to the mudstone to drill its first sample in a year and half. If the oven and mass spectrometer reveal signs of organics in the sample, the team is likely to use a cup. “It’s getting so close I can taste it,” says Ashwin Vasavada, Curiosity’s project scientist at the Jet Propulsion Laboratory in Pasadena, California.

The newest drillhole sample has now entered the mass spectrometer. Stay tuned!

4 comments

Movie of Juno’s thirteenth fly-by of Jupiter

10:12 am

Cool image time. Mathematician and software programmer Gerald Eichstädt has released another movie using images from Juno’s thirteenth close fly-by of Jupiter.

I have embedded the movie below the fold. As he notes,

The movie covers two hours of this flyby in 125-fold time lapse, the time from 2018-05-24T04:41:00.000 to 2018-05-24T06:41:00.000. It is based on 27 of the JunoCam images taken during the flyby, and on spacecraft trajectory data provided via SPICE kernel files.

The view begins by looking down at the northern hemisphere, and gets to within 2,200 miles of the giant planet’s cloud tops.

» Read more

3 comments

New data widens the margin of error in carbon dating

5:21 pm

The uncertainty of science: New data suggests that the accuracy of carbon-14 dating, used mostly in archaeology and research covering the last few thousand years, has a wider margin of error than previously thought.

By measuring the amount of carbon-14 in the annual growth rings of trees grown in southern Jordan, researchers have found some dating calculations on events in the Middle East – or, more accurately, the Levant – could be out by nearly 20 years.

That may not seem like a huge deal, but in situations where a decade or two of discrepancy counts, radiocarbon dating could be misrepresenting important details.

To me, it seems somewhat arrogant for any scientist to assume this dating could be more accurate than this, especially going back several thousand years and especially considering the number of factors described in the article that they have account for and make assumptions about.

Nonetheless, documenting this margin of error means that the arrogant scientists of the future will have to include it in their research, rather than making believe it doesn’t exist.

4 comments

Juno mission extended

3:31 pm

NASA has extended the Juno mission through 2022 in order to complete its planned science.

NASA has approved an update to Juno’s science operations until July 2021. This provides for an additional 41 months in orbit around Jupiter and will enable Juno to achieve its primary science objectives.Juno is in 53-day orbits rather than 14-day orbits as initially planned because of a concern about valves on the spacecraft’s fuel system. This longer orbit means that it will take more time to collect the needed science data.

An independent panel of experts confirmed in April that Juno is on track to achieve its science objectives and is already returning spectacular results.The Juno spacecraft and all instruments are healthy and operating nominally.

NASA has now funded Juno through FY 2022. The end of prime operations is now expected in July 2021, with data analysis and mission close-out activities continuing into 2022.

I will admit that though Juno is clearly learning a great deal about Jupiter, such as this story about lightning there, its larger orbit makes it difficult to track the gas giant cloud structures as they evolve. This is unfortunate.

Leave a comment

More problems for James Webb Space Telescope?

9:45 am

The impending release of an independent NASA review of the state of the James Webb Space Telescope project suggests that the project is faced with additional issues.

NASA is in the process of evaluating the report from the Independent Review Board chaired by Tom Young to assess the status of the James Webb Space Telescope (JWST). Established in March, the Board was due to submit its report on May 31. NASA said today that the Board has completed its work and briefed NASA. The report will be released later this month after NASA determines the impact on cost and schedule.

Thomas Zurbuchen, NASA Associate Administrator for the Science Mission Directorate, created the Webb Independent Review Board (WIRB) on March 27, the same day he announced another delay in the telescope’s launch. WIRB held its first meeting the next week.

For many years, JWST appeared to be on track for launch in October 2018 after a 2011 restructuring that followed a series of earlier cost overruns and schedule delays. Congress capped the development cost (not operations) at $8 billion in law. Pursuant to the 2005 NASA Authorization Act, if a program exceeds 30 percent of its baseline estimated cost, NASA must notify Congress and no money may be spent on it after 18 months from the time of that notification unless Congress reauthorizes it.

The project will not die, Congress will simply extend it with lots more money. That is how big NASA projects really function, to take as long as possible so that they can continue their real goal of providing pork barrel jobs in congressional districts.

4 comments

Democrats generally reject scientist candidates

9:38 am

In yesterday’s primary elections, scientists running as Democrats generally did poorly.

Science-minded candidates seeking seats in the next U.S. Congress took a drubbing from their Democratic opponents in yesterday’s raft of primary elections across the country.

Voters went to the polls Tuesday in eight states to choose nominees for the November elections. And none of the candidates who touted their scientific credentials—a list that includes volcanologist Jess Phoenix, technologist Brian Forde, pediatrician Mai Khanh Tran, and geophysicist Grant Kier—won their contested contests. In one California district, neuroscientist Hans Keirstead is trailing in a race that is still too close to call.

This article in the journal Science is fun to read in that it blatantly reveals that journal’s partisan Democratic Party leanings: the goal is to beat Republicans, and the hope was that scientists would do it. For the scientists however, it turns out that Democratic Party voters really don’t like science and the skeptical demands it requires.

Kind of reminds me of the secular liberal Jews who blindly vote Democratic, even as that party works to betray them.

Leave a comment

China offers big bucks to attract foreign science talent

9:10 am

Link here. In China’s recent push to build big science facilities, such as the giant radio telescope FAST, it has faced a shortage of qualified homegrown Chinese scientists to run those new facilities.

To solve this problem, China is now offering big bucks to any scientist, even foreigners, willing to move to China.

On 22 May, the Ministry of Science and Technology issued guidelines that encourage science ministries and commissions to consult foreign experts and attract non-Chinese to full-time positions within China. In a striking change, foreign scientists are now allowed to lead public research projects.

In the past decade, China has aimed to build up its scientific capacity by luring back some of the tens of thousands of Chinese scientists working abroad. The latest measures emphasize that non-Chinese talent is also welcome. Drafted in December 2017 but not previously made public, they are “a confirmation of things that have been going on for a while,” says Denis Simon, an expert on China’s science policy at Duke Kunshan University in China, a branch campus of the Durham, North Carolina–based Duke University.

Simon says foreign scientists are drawn by China’s increased spending on R&D, which is rising twice as fast as its economic growth. Increasingly ambitious big science projects, such as a massive particle accelerator now under study, are a lure as well, says Cao Cong, a science policy specialist at the University of Nottingham Ningbo in China, an affiliate of the U.K. university. The opportunity for foreign scientists to serve as principal investigators for publicly funded programs is a significant new incentive, says Liang Zheng, who studies science and technology policy at Tsinghua University in Beijing.

Of course, moving to a nation ruled under totalitarian communist rule has its drawbacks:

Relocating to China comes with challenges. Gibson teaches in English but needs Chinese language help handling administrative matters and grant applications. Restricted access to internet sites such as Google is also a hurdle. “My research and my teaching regularly rely on access to online resources and search platforms [that are] blocked in China, so this is an impediment to my work,” Gibson says. But he has found workarounds. China shut down many virtual private networks, which provide access to blocked overseas sites, but a few remain. “There’s a saying: ‘Everything in China is difficult, but nothing is impossible,’ which I think reflects the situation very accurately,” Gibson says.

I would also expect that any American who makes this move will face significant security problems with the U.S. government upon their return.

Leave a comment

Another intriguing pit on Mars

1:37 pm

pit on Mars

Cool image time! In the June release of images from the high resolution camera on Mars Reconnaissance Orbiter, I came across the image on the right, cropped slightly to post here, of a pit in a region dubbed Hephaestus Fossae that is located just at the margin of Mars’s vast northern plains.

Below and to the right is an annotated second image showing the area around this pit. If you click on it you can see the full resolution image, uncropped, and unannotated.

wider view of pit

The scale bar is based on the 25 centimeter per pixel scale provided at the image link. Based on this, this pit is only about ten to fifteen meters across, or 30 to 50 feet wide. The image webpage says the sun was 39 degrees above the horizon, with what they call a sun angle of 51 degrees. Based on these angles, the shadow on the floor of the pit suggests it is about the same depth, 30 to 50 feet.

The shadows suggest overhung walls. This, plus the presence of nearby aligned sinks, strongly suggests that there are extensive underground passages leading away from this pit.

For a caver on Earth to drop into a pit 30 to 50 feet deep is nowadays a trivial thing. You rig a rope (properly), put on your vertical system, and rappel in. When you want to leave you use that same vertical system to climb the rope, using mechanical cams that slide up the rope but will not slide down.

On Mars such a climb would be both easier and harder. The gravity is only one third that of Earth, but the lack of atmosphere means you must wear some form of spacesuit. Moreover, this system is not great for getting large amounts of gear up and down. Usually, people only bring what they can carry in a pack. To use this Martian pit as a habitat will require easier access, preferable by a wheeled vehicle that can drive in.

The pit’s location however is intriguing. The map below shows its location on a global map of Mars. This region is part of the Utopia Basin, the place with the second lowest elevation on Mars.
» Read more

7 comments

No giant planet needed in Kuiper Belt to shape orbits of outer known planets

9:27 am

Using computer models astronomers have found that the tiny objects in the Kuiper Belt could be sufficient, instead of one giant undiscovered planet, to provide the gravity necessary to explain the orbits of the solar system’s outer planets.

They call theorized giant planet “Planet Nine,” which seems silly since Pluto really still fills that role. Nonetheless, this work also might explain the process that flung some surprisingly large objects so far out into the Kuiper Belt.

They ran supercomputer simulations of how bodies might interact in the outer Solar System far beyond Pluto, in the icy region known as the Kuiper belt. They found that a flock of Moon-sized worlds could do many of the same things as Planet Nine.

Over millions of years, the collective gravity of these smaller worlds would nudge the orbits of distant objects. The worlds would jostle one another like bumper cars and, occasionally, cause an object to move into a very distant orbit. Their simulations suggest that more-massive objects would be flung into the most distant orbits — as some observations have suggested.

We must also remind ourselves that this conclusion is based on a computer model, and is filled with uncertainty. We also do not yet have a full census of objects in the Kuiper Belt, which means this model required many assumptions.

Leave a comment

New Horizons awakened to begin preparations for January 1 2019 flyby

9:07 am

The New Horizons engineering team has brought the spacecraft out of hibernation to begin preparations for its January 1 2019 flyby of Kuiper Belt object 2014 MU69, which they have dubbed Ultima Thule.

New Horizons will begin its approach phase of the MU69 flyby on August 16, 2018, when it will begin imaging MU69 and the area around it to begin acquiring data about the KBO and its surroundings. Also, New Horizons will look for potential debris that could pose a hazard to itself, such as moons or rings.

Should any potential dangers be found, New Horizons has four planned opportunities to make trajectory changes from early October to early December 2018. The backup trajectory has a distance from MU69 of 10,000 kilometers (around 6,200 miles). Using the backup trajectory would lead to less and/or lower-quality science data gathered due to the probe flying by MU69 further away than planned.

The approach phase will last from August 16 to December 24, 2018, after which the core phase will begin.

The core phase begins just one week before the flyby and continues until two days afterward. It contains the flyby and the majority of the data gathering.

Based on this schedule, we should begin to get some interesting pictures of Ultima Thule by the fall.

Leave a comment

Curiosity’s new drilling technique declared a success

1:15 pm

In order to bypass a failed feed mechanism in the rover’s drill, Curiosity’s engineering team has declared successful the new techniques they have developed for drilling and getting samples.

They had successfully completed a new drill hole two weeks ago, but are only now are satisfied that the new method for depositing samples in the laboratories will work.

This delivery method had already been successfully tested at JPL. But that’s here on Earth; on Mars, the thin, dry atmosphere provides very different conditions for powder falling out of the drill. “On Mars we have to try and estimate visually whether this is working, just by looking at images of how much powder falls out,” said John Michael Moorokian of JPL, the engineer who led development of the new sample delivery method. “We’re talking about as little as half a baby aspirin worth of sample.”

Too little powder, and the laboratories can’t provide accurate analyses. Too much, and it could overfill the instruments, clogging parts or contaminating future measurements. A successful test of the delivery method on May 22 led to even further improvements in the delivery technique.

Part of the challenge is that Curiosity’s drill is now permanently extended. That new configuration no longer gives it access to a special device that sieves and portions drilled samples in precise amounts. That device, called the Collection and Handling for In-Situ Martian Rock Analysis (CHIMRA), played an important role in delivering measured portions of sample to the laboratories inside the rover.

I suspect that they still need to do more tests, and that the new method of shaking off material from the drill itself will not always work. At the same time, it reopens the option of using the drill and getting samples from it, which is a very good thing.

Leave a comment

Globular clusters not as old as universe?

9:04 am

The uncertainty of science: A new computer model, based on binary star systems found in globular clusters, now estimates that those clusters are far younger than previously believed.

Comprised of hundreds of thousands of stars densely packed into a tight ball, globular clusters had been thought to be almost as old as the Universe itself – but thanks to newly developed research models it has been shown that they could be as young as 9 billion years old rather than 13 billion. The discovery brings into question current theories on how galaxies, including the Milky Way, were formed – with between 150-180 clusters thought to exist in the Milky Way alone – as globular clusters had previously been thought to be almost as old as the Universe itself.

Designed to reconsider the evolution of stars, the new Binary Population and Spectral Synthesis (BPASS) models take the details of binary star evolution within the globular cluster into account and are used to explore the colours of light from old binary star populations – as well as the traces of chemical elements seen in their spectra. The evolutionary process sees two stars interacting in a binary system, where one star expands into a giant whilst the gravitational force of the smaller star strips away the atmosphere, comprising hydrogen and helium amongst other elements, of the giant. These stars are thought to be formed as the same time as the globular cluster itself.

Through using the BPASS models and calculating the age of the binary star systems the researchers were able to demonstrate that the globular cluster of which they are part was not as ancient as other models had suggested.

All this study really does is demonstrate again that we really don’t know enough to make a very accurate estimate of the ages of globular clusters. They are very old, but determining precisely how old will require a lot more knowledge.

One comment

Boulder-sized asteroid discovered just before it hit Earth

8:59 am

The Catalina Sky Survey, designed to find asteroid with the potential of hitting the Earth, discovered a boulder-sized such asteroid this past weekend just hours before it burned up in the atmosphere.

Although there was not enough tracking data to make precise predictions ahead of time, a swath of possible locations was calculated stretching from Southern Africa, across the Indian Ocean, and onto New Guinea. Reports of a bright fireball above Botswana, Africa, early Saturday evening match up with the predicted trajectory for the asteroid. The asteroid entered Earth’s atmosphere at the high speed of 10 miles per second (38,000 mph, or 17 kilometers per second) at about 16:44 UTC (9:44 a.m. PDT, 12:44 p.m. EDT,6:44 p.m. local Botswana time) and disintegrated several miles above the surface, creating a bright fireball that lit up the evening sky. The event was witnessed by a number of observers and was caught on webcam video.

When it was first detected, the asteroid was nearly as far away as the Moon’s orbit, although that was not initially known. The asteroid appeared as a streak in the series of time-exposure images taken by the Catalina telescope . As is the case for all asteroid-hunting projects, the data were quickly sent to the Minor Planet Center in Cambridge, Massachusetts, which calculated a preliminary trajectory indicating the possibility of an Earth impact. The data were in turn sent to the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory in Pasadena, California, where the automated Scout system also found a high probability that the asteroid was on an impact trajectory. Automated alerts were sent out to the community of asteroid observers to obtain further observations, and to the Planetary Defense Coordination Office at NASA Headquarters in Washington. However, since the asteroid was determined to be so small and therefore harmless, no further impact alerts were issued by NASA.

The video at the link makes it appear that the asteroid has hit the ground, but that is not what happened.

Leave a comment

The surface properties of 122 asteroids revealed

1:12 pm

Using archive data produced by the Wide-field Infrared Explorer telescope (WISE, renamed NEOWISE) astronomers have been able to estimate the surface properties of 122 small asteroids located in the asteroid belt.

“Using archived data from the NEOWISE mission and our previously derived shape models, we were able to create highly detailed thermophysical models of 122 main belt asteroids,” said Hanuš, lead author of the paper. “We now have a better idea of the properties of the surface regolith and show that small asteroids, as well as fast rotating asteroids, have little, if any, dust covering their surfaces.” (Regolith is the term for the broken rocks and dust on the surface.)

It could be difficult for fast-rotating asteroids to retain very fine regolith grains because their low gravity and high spin rates tend to fling small particles off their surfaces and into space. Also, it could be that fast-rotating asteroids do not experience large temperature changes because the sun’s rays are more rapidly distributed across their surfaces. That would reduce or prevent the thermal cracking of an asteroid’s surface material that could cause the generation of fine grains of regolith. [emphasis mine]

If this conclusion holds, it means that mining these asteroids might be much easier. Dust can be a big problem, as it can clog up equipment and interfere with operations. It also acts to hide the underlying material, making it harder to find the good stuff.

Leave a comment

Heavier astronauts more likely to have vision issues in zero-G

9:51 am

An analysis of the physical characteristics of astronauts who develop vision problems after long missions in weightlessness has found that heavier body weight increases the risk.

The research team examined data collected by NASA from astronauts who had made long-duration space flights (averaging 165 days). The data included the astronauts’ sex and pre-flight height, weight, waist and chest size, as well as information about post-flight eye changes. The findings were related to body weight, not body mass index. They found that none of the female astronauts analyzed—who weighed less than the males—returned to Earth with symptoms of SANS. To rule out sex differences as a cause for the disparity, the researchers also examined the men’s data separately. “Pre-flight weight, waist circumference and chest circumference were all significantly greater in those who developed either disc edema or choroidal folds. This was still true when only the male cohort was analyzed,” the researchers wrote. “The results from this study show a strong relationship between body weight and the development of ocular changes in space.”

That such small differences in weight can make such a difference suggests again that adding just a small amount of artificial gravity, rather than 1g, might mitigate these issues. No tests of this however have ever been done, mostly because the engineering is complex and expensive. For humans we would need to build a vessel large enough that any rotation would be unnoticed. If the vessel is small it must rotate faster and the body’s inner ear gets confused. However, if we only need to simulate a tiny amount of gravity the spin rate can be reduced, simplifying the engineering.

One comment

Dunes on Pluto?

9:14 am

Dunes on Pluto

Cool image time! Scientists reviewing images taken by New Horizons when it flew past Pluto in 2015 have discovered what appear to be dunes of methane on the icepack of nitrogen of Sputnik Planitia. The image on the right, cropped to post here, shows these dunes. You can see the full image if you click on it.

Following spatial analysis of the dunes and nearby wind streaks on the planet’s surface, as well as spectral and numerical modelling, scientists believe that sublimation (which converts solid nitrogen directly into a gas) results in sand-sized grains of methane being released into the environment.

These are then transported by Pluto’s moderate winds (which can reach between 30 and 40 kmh), with the border of the ice plain and mountain range providing the perfect location for such regular surface formations to appear.

The scientists also believe the undisturbed morphology of the dunes and their relationship with the underlying glacial ice suggests the features are likely to have been formed within the last 500,000 years, and possibly much more recently.

There remains a lot of uncertainty here. The features do look like dunes in the image, but it is also possible that other phenomenon not yet understood could have caused this pattern on the icepack surface. Also, the resolution of the image is not sufficient to really see detail at this level. A different process on the surface could be fooling our eyes.

Nonetheless, the scientists hypothesis makes sense, and fits the data known. It also demonstrates again that, even billions of miles from the Sun, in as alien an environment we can imagine, the planet Pluto is an active and complex place.

Leave a comment

Astronomers identify giant exoplanets that might harbor habitable moons

11:57 am

Worlds without end: In reviewing the known exoplanets astronomers have identified more than a hundred giant exoplanets located in the habitable zone that might harbor habitable moons.

The researchers identified 121 giant planets that have orbits within the habitable zones of their stars. At more than three times the radii of the Earth, these gaseous planets are less common than terrestrial planets, but each is expected to host several large moons.

Scientists have speculated that exomoons might provide a favorable environment for life, perhaps even better than Earth. That’s because they receive energy not only from their star, but also from radiation reflected from their planet. Until now, no exomoons have been confirmed.

Using this new database scientists will optimize future instruments on both the ground and in space to look for and study the moons circling these exoplanets.

Leave a comment
1 … 122 123 124 125 126 … 272