Tag: science

An ancient ocean on Ceres?

10:03 am

Two studies released today by the Dawn science team suggest that the spacecraft has found evidence that an ancient ocean once existed on Ceres.

In one study, the Dawn team found Ceres’ crust is a mixture of ice, salts and hydrated materials that were subjected to past and possibly recent geologic activity, and this crust represents most of that ancient ocean. The second study builds off the first and suggests there is a softer, easily deformable layer beneath Ceres’ rigid surface crust, which could be the signature of residual liquid left over from the ocean, too.

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Scientists propose adding smog to atmosphere to fight global warming

9:44 am

What could possibly go wrong? Global warming scientists have proposed injecting sulphate aerosols (another name for pollution) into the upper atmosphere in order to counter their predicted global temperature rise.

Experts are considering ploughing sulphate aerosols into the upper atmosphere which would cause some of the suns rays to be reflected back out into space. This could potentially cool the Earth down and help counter the effects of climate change, scientists say.

The move would also help reduce coral bleaching and help calm powerful storms.

James Crabbe, from the University of Bedfordshire, is leading the study and his initial results suggest the plan could help cool the planet.

This proposal is based on such flimsy science it appalls me that any scientist would even consider it, especially when you think about the unknown consequences.

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Rosetta’s capture of a dust jet from Comet 67P/C-G

9:26 am

Dust jet on Comet 67P/C-G

Cool image time! The Rosetta science team has released images and data gathered in July 2016 when the spacecraft successfully observed a dust outburst erupting from Comet 67P/C-G’s surface. The image on the right, slightly reduced in resolution, shows that outburst.

When the Sun rose over the Imhotep region of Rosetta’s comet on July 3, 2016, everything was just right: As the surface warmed and began to emit dust into space, Rosetta’s trajectory led the probe right through the cloud. At the same time, the view of the scientific camera system OSIRIS coincidentally focused precisely on the surface region of the comet from which the fountain originated. A total of five instruments on board the probe were able to document the outburst in the following hours.

As should be expected, the results did not match the models or predictions. The jet, instigated by water-ice just below the surface turning into gas when heated by the Sun, was much dustier than predicted. They have theories as to why, but it appears that no one likes these theories that much.

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The first large object identified coming from interstellar space

6:38 pm

Astronomers think they have spotted the first large object to come from beyond the solar system.

Based on its apparent brightness, dynamicist Bill Gray calculates that it would have a diameter of about 160 meters (525 feet) if it were a rock with a surface reflectivity of 10%. “It went past the Sun really fast,” Gray notes, “and may not have had time to heat up enough to break apart.”

Now it’s headed out of the solar system, never to return. It passed closest to Earth on October 14th at a distance of about 24,000,000 km (15,000,000 miles), and astronomers worldwide have been tracking it in the hopes of divining its true nature — especially whether it’s displaying any cometary activity.

…According to Gray, Comet PanSTARRS appears to have entered the solar system from the direction of the constellation Lyra, within a couple of degrees of right ascension 18h 50m, declination +35° 13′. That’s tantalizingly close to Vega — and eerily reminiscent of the plot of the movie Contact — but its exact path doesn’t (yet) appear to link any particular star.

This object entered the solar system moving at 26 km (16 miles) per second. At that speed, in 10 million years it would traverse 8,200,000,000,000,000 km — more than 850 light-years.

Reminds me of a really good science fiction novel I read recently. They should keep an eye on it for as long as they can, just in case it suddenly changes course and settles into a more circular orbit around the Sun. In the unlikely case it does that, it might just be the biggest discovery in history.

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Squiggles on Mars

9:17 am

Squiggles on Mars

Cool image time! The image on the right, reduced and cropped to post here, shows a sand dune slope with numerous squiggly troughs that end either in a small pit or slowly fade away. At first glance one things the troughs were caused by a boulder rolling downhill, but there are no boulders at the base of the slope, and a rolling boulder wouldn’t create so many similar squiggles like this.

The explanation is that the boulders are made of carbon dioxide ice.

Just like on Earth, high-latitude regions on Mars are covered with frost in the winter. However, the winter frost on Mars is made of carbon dioxide ice (dry ice) instead of water ice. We believe linear gullies are the result of this dry ice breaking apart into blocks, which then slide or roll down warmer sandy slopes, sublimating and carving as they go.

The linear gullies exhibit exceptional sinuosity (the squiggle pattern) and we believe this to be the result of repeated movement of dry ice blocks in the same path, possibly in combination with different hardness or flow resistance of the sand within the dune slopes.

For a really entertaining explanation of this process, take a look at the embedded video below the fold.
» Read more

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Since 2016 almost a 1000 published papers have challenged the theory of human-caused climate change

9:02 am

Link here. What the author does is quote from numerous scientific papers where they either note the lack of evidence that human activity has caused the recent warming of the climate since the 1600s, or note other natural phenomenon where the evidence of influence is far stronger. Here’s one example:

Rosenblum and Eisenman, 2017

Observations indicate that the Arctic sea ice cover is rapidly retreating while the Antarctic sea ice cover is steadily expanding. State-of-the-art climate models, by contrast, typically simulate a moderate decrease in both the Arctic and Antarctic sea ice covers.

Here’s another, with a link to the actual peer-reviewed published paper:

Blaauw, 2017 [pdf]

This paper demonstrates that global warming can be explained without recourse to the greenhouse theory

He quotes many more, and has found 900 papers since 2016 that challenge the accepted-wisdoms pushed by global-warming theories.

The point here is not to say the climate doesn’t change, or that increased CO2 is not a concern, but to point out that the science is not settled, and anyone who makes that claim is either ignorant, or lying.

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Engineers develop new technique to resume drill use on Curiosity

12:27 pm

Engineers have successfully tested a new drill procedure on a duplicate rover on Earth that bypasses the problem in Curiosity’s drill.

The problem with the drill has been its feed mechanism, which pushes the drill bit downward as it drills its hole. The tests with the duplicate rover on Earth have instead had the drill bit fully extended and used the robot arm itself to push downward. It worked, but the problem on Mars is holding the drill bit perfectly straight and not slipping sideways. They are now doing a test with Curiosity to address this.

Curiosity touched its drill to the ground Oct. 17 for the first time in 10 months. It pressed the drill bit downward, and then applied smaller sideways forces while taking measurements with a force sensor. “This is the first time we’ve ever placed the drill bit directly on a Martian rock without stabilizers,” said JPL’s Douglas Klein, chief engineer for the mission’s return-to-drilling development. “The test is to gain better understanding of how the force/torque sensor on the arm provides information about side forces.”

This sensor gives the arm a sense of touch about how hard it is pressing down or sideways. Avoiding too much side force in drilling into a rock and extracting the bit from the rock is crucial to avoid having the bit get stuck in the rock.

Stay tuned for a Mars rover update, coming shortly!

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The glory of Cassini’s Saturn

8:31 am

The glory of Saturn

Cool image time! The image on the right, reduced in resolution to post here, was taken by Cassini on August 17, 2017, one month before the spacecraft dived into Saturn to end its mission.

This view looks toward the sunlit side of the rings from about 19 degrees above the ringplane. The image was taken in green light with the Cassini spacecraft wide-angle camera on Aug. 12, 2017. Pandora was brightened by a factor of 2 to increase its visibility.

The view was obtained at a distance to Saturn of approximately 581,000 miles (935,000 kilometers) from Saturn. Image scale is 35 miles (56 kilometers) per pixel. The distance to Pandora was 691,000 miles (1.1 million kilometers) for a scale of 41 miles (66 kilometers) per pixel.

The moon Pandora can be seen in the full resolution image just beyond the outermost ring near the top of the screen.

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Iranian scientist sentenced to death

8:13 am

An Iranian judge has sentenced an Iranian scientist to execution in 20 days.

The scientist, who appears to have mostly worked in Sweden, was convicted of spying for Israel. He in turn says he was railroaded because he refused to spy on his colleagues for the Iranian intelligence service.

What baffles me here is that he was arrested when returned to Iran for a short visit. He must have known that going back was going to put him in great risk. Why do it?

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NASA instrument for European space telescope flawed and must be rebuilt

5:29 pm

The NASA instrument for Europe’s Euclid optical/near-infrared space telescope has been found defective and must be rebuilt, thus delaying the launch of the telescope by at least one year.

What interested me about this telescope is its goals and specifications:

Euclid is a two-ton space telescope selected by ESA in 2011 as a medium-class mission in its Cosmic Vision program of space science missions. The spacecraft features a 1.2-meter telescope with visible and near-infrared instruments to study dark energy and dark matter, which combined account for about 95 percent of the universe. Euclid will operate at the Earth-sun L-2 Lagrange point, 1.5 million kilometers from Earth, that is used by other infrared astronomy missions.

With a mirror about half the size of Hubble’s, this telescope will act as a partial replacement and back up for it. In fact, it will likely make numerous ground-breaking discoveries, as every optical telescope placed above the atmosphere has so far done.

Meanwhile, the article provided no information on the flaws, who built the flawed instrument, and who will pay for the delays its failure will cause.

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Juno’s first hints of Jupiter’s interior

5:17 pm

Data from Juno not only suggests that the gas giant has a small fuzzy core, its storms appear to extend thousands of miles into the interior.

By studying Jupiter’s gravitational field, researchers can probe thousands of kilometres into the planet. On each close fly-by, Juno measures the planet’s complex gravitational tug. These observations have already revealed that Jupiter has a small, ‘fuzzy’, poorly defined core.

The latest results show that Jupiter’s gravitational field is askew, with different patterns in its northern and southern hemispheres, said Tristan Guillot, a planetary scientist at the Observatory of the Côte d’Azur in Nice, France. That suggests that its hydrogen-rich gas is flowing asymmetrically deep in the planet. “This is something that was not expected,” Guillot said at the meeting. “We were not sure at all whether we would be able to see that.”

Another clue to the structure of Jupiter’s interior came from how the gravity field varies with depth. Theoretical studies predict that the bigger the gravity signal, the stronger the flow of gas deep down. That information is important for teasing out whether all of Jupiter’s interior is rotating as a single solid body, or whether different layers spin separately from one another, like a set of nesting Russian dolls moving within each other.

Juno detected a gravity signal powerful enough to indicate that material is flowing as far down as 3,000 kilometres. “We’re just taking the clouds and the winds and extending them into the interior,” Kaspi said. Future work could help to pinpoint how strong the flow is at various depths, which could resolve whether Jupiter’s interior really resembles Russian dolls.

What is especially fascinating is that this first study of Jupiter shows it to appear so very different than Cassini’s first look at Saturn. Their polar regions are completely different, their storms are different, even their horizontal bands behave and look different. As I’ve said numerous times, the one given in planetary exploration is that every single planetary object we look at will be completely different from every other object.

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NASA extends Dawn’s mission orbiting Ceres

2:11 pm

NASA has decided to extend the Dawn mission again, but have that extension remain in orbit around Ceres.

A priority of the second Ceres mission extension is collecting data with Dawn’s gamma ray and neutron spectrometer, which measures the number and energy of gamma rays and neutrons. This information is important for understanding the composition of Ceres’ uppermost layer and how much ice it contains.

The spacecraft also will take visible-light images of Ceres’ surface geology with its camera, as well as measurements of Ceres’ mineralogy with its visible and infrared mapping spectrometer.

The extended mission at Ceres additionally allows Dawn to be in orbit while the dwarf planet goes through perihelion, its closest approach to the Sun, which will occur in April 2018. At closer proximity to the Sun, more ice on Ceres’ surface may turn to water vapor, which may in turn contribute to the weak transient atmosphere detected by the European Space Agency’s Herschel Space Observatory before Dawn’s arrival. Building on Dawn’s findings, the team has hypothesized that water vapor may be produced in part from energetic particles from the Sun interacting with ice in Ceres’ shallow surface.Scientists will combine data from ground-based observatories with Dawn’s observations to further study these phenomena as Ceres approaches perihelion.

They aim to get as close as 120 miles of the surface during this extension, half as close as the previous closest approach.

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NASA and Australia sign extension of space-tracking agreement

8:39 am

NASA and Australia have signed an extension of the treaty that allowed for the construction and operation of antennas in Australia used by NASA’s Deep Space Network.

Australia’s ambassador to the US, Joe Hockey, signed the Space Tracking Treaty on behalf of Australia, with the acting administrator of NASA, Robert Lightfoot, signing on behalf of the US, at a ceremony at the Australian Embassy in Washington DC.

The treaty covers civil space facilities owned by NASA and located within Australia, including the Canberra Deep Space Communication Complex at Tidbinbilla, as well as facilities in Western Australia and the Northern Territory.

That the treaty signing was turned into a photo-op, something that previous signings did not require, suggests to me that Australia’s politicians are planning bigger things for their future space program.

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Thirty mile cave on the Moon?

8:34 am

A new analysis of data from Japan’s Kaguya lunar orbiter suggests that one of the cave pits it found could be an entrance to a lava tube 30 miles long.

In 2009, the Kaguya probe found a large shaft with an opening about 50 meters in diameter in the Marius Hills area. The shaft descends about 50 meters beneath the surface.

The JAXA team analyzed data obtained from a lunar radar sounder on the probe that indicated an underground structure extended west from the shaft. The study confirmed that the cavern, likely created by volcanic activity, has not collapsed, and there is the possibility of ice or water existing in rocks within the cave, the team said.

Do a search on Behind the Black using the search terms “cave” and “moon” and you will see many images of this pit, taken by Lunar Reconnaissance Orbiter as a follow-up to the Kaguya mission.

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Astronomers reduce estimate of still undiscovered dangerous asteroids

11:49 am

Astronomers have now reduced [pdf] their estimate of the number of still undiscovered dangerous Near Earth Asteroids (NEAs) that could impact the Earth from 100 to less than 40.

Observers have been cataloging potentially hazardous asteroids for decades. Based on the number of finds, the area of sky explored, and the limiting brightness our telescopes and cameras can reach, researchers can estimate what fraction of the NEA population has been detected so far and how many more objects lurk undiscovered. Harris has published numerous such estimates over the years. Recently he realized that his estimates have been plagued by a seemingly innocuous but nonetheless consequential round-off error. Once corrected, the estimated number of large (diameter > 1 kilometer) NEAs remaining to be discovered decreases from more than 100 to less than 40.

To put it mildly, there is a lot of uncertainty here. This also reminds me of the cavers’ joke question: “How many miles of unexplored passages does this cave have?”

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Nearby asteroid orbits both the Earth and the Sun

11:42 am

Worlds without end: Astronomers have determined that a recently discovered object with a weird solar orbit that also has it loop around the Earth each year is an asteroid, not space junk.

The asteroid is dubbed 2016 HO3. What is most interesting about this story to me however was this tidbit:

“Of the near-Earth objects we know of, these types of objects would be the easiest to reach, so they could potentially make suitable targets for exploration,” said Veillet, director of the LBT Observatory. “With its binocular arrangement of two 8.4-meter mirrors, coupled with a very efficient pair of imagers and spectrographs like MODS, LBT is ideally suited to the characterization of these Earth’s companions.”

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New findings from Cassini’s final months

11:49 am

Link here. Among a bunch of other interesting results, this one I found the most tantalizing:

The spacecraft’s Ion and Neutral Mass Spectrometer (INMS) returned a host of first-ever direct measurements of the components in Saturn’s upper atmosphere, which stretches almost to the rings. From these observations, the team sees evidence that molecules from the rings are raining down onto the atmosphere. This influx of material from the rings was expected, but INMS data show hints of ingredients more complex than just water, which makes up the bulk of the rings’ composition. In particular, the instrument detected methane, a volatile molecule that scientists would not expect to be abundant in the rings or found so high in Saturn’s atmosphere.

The results generally leave behind more questions than answers, but that is exactly why exploring the universe is so much fun.

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Europe’s Trace Gas Orbiter detects clouds over Martian volcano

9:31 am

Europe’s Trace Gas Orbiter (TGO) has detected clouds over the western slopes of the giant Martian volcano Arsia Mons.

This is not a new discovery, merely a confirmation of many past observations, all of which suggest that water-ice glaciers once flowed down those western slopes, and that some of that ice remains trapped in underground caves and lava tubes there. Undeniably this region appears at present to be the most valuable real estate on Mars. It has caves where the first colonies can be more easily built. Those caves likely have water in them. And the location is near the equator, which is easier to reach and also makes the environment somewhat less hostile.

TGO is presently slowly aerobraking itself down to its planned science orbit, which it is expected to reach in 2018.

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Astronomers detect neutron star merger in both light and gravitational waves

9:00 am

Big news! Astronomers from dozens of telescopes on the ground and in space have observed for the first time the light burst caused by the merger of two neutron stars because earlier observations of the merger’s gravitational wave and gamma ray burst told them where to look in the sky.

On 17 August 2017 the NSF’s Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States, working with the Virgo Interferometer in Italy, detected gravitational waves passing the Earth. This event, the fifth ever detected, was named GW170817. About two seconds later, two space observatories, NASA’s Fermi Gamma-ray Space Telescope and ESA’s INTErnational Gamma Ray Astrophysics Laboratory (INTEGRAL), detected a short gamma-ray burst from the same area of the sky.

The LIGO–Virgo observatory network positioned the source within a large region of the southern sky, the size of several hundred full Moons and containing millions of stars. As night fell in Chile many telescopes peered at this patch of sky, searching for new sources. These included ESO’s Visible and Infrared Survey Telescope for Astronomy (VISTA) and VLT Survey Telescope (VST) at the Paranal Observatory, the Italian Rapid Eye Mount (REM) telescope at ESO’s La Silla Observatory, the LCO 0.4-meter telescope at Las Cumbres Observatory, and the American DECam at Cerro Tololo Inter-American Observatory. The Swope 1-metre telescope was the first to announce a new point of light. It appeared very close to NGC 4993, a lenticular galaxy in the constellation of Hydra, and VISTA observations pinpointed this source at infrared wavelengths almost at the same time. As night marched west across the globe, the Hawaiian island telescopes Pan-STARRS and Subaru also picked it up and watched it evolve rapidly.

Press releases today from numerous other observatories are too numerous to link here, and most essentially say the same thing. The key facts so far gleaned however are intriguing:

Distance estimates from both the gravitational wave data and other observations agree that GW170817 was at the same distance as NGC 4993, about 130 million light-years from Earth. This makes the source both the closest gravitational wave event detected so far and also one of the closest gamma-ray burst sources ever seen

This event also highlights the advantages of observing the universe in as many ways as possible. Some phenomenon get to us sooner, and thus provide us clues on where to look with other tools. Without the gravitational wave and gamma ray burst detectors, on Earth and in space, the other optical and infrared telescopes would have almost certainly not have recorded this merger.

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Storms on Titan dump a lot of liquid methane, quickly

3:16 pm

A new climate model for Titan that suggests the planet’s methane rainstorms occur about once a Saturn year (29.5 years) and at about 60 degree latitude correlates with Cassini surface data that found a high concentration of alluvial fans at that latitude.

“The most intense methane storms in our climate model dump at least a foot of rain a day, which comes close to what we saw in Houston from Hurricane Harvey this summer,” said Mitchell, the principal investigator of UCLA’s Titan climate modeling research group.

Sean Faulk, a UCLA graduate student and the study’s lead author said the study also found that the extreme methane rainstorms may imprint the moon’s icy surface in much the same way that extreme rainstorms shape Earth’s rocky surface. On Earth, intense storms can trigger large flows of sediment that spread into low lands and form cone-shaped features called alluvial fans. In the new study, the UCLA scientists found that regional patterns of extreme rainfall on Titan are correlated with recent detections of alluvial fans, suggesting that they were formed by intense rainstorms.

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