Tag: science

Cause of vision problems in space pinpointed?

9:12 am

New research suggests that scientists have pinpointed the cause of the vision problems astronauts experience from long term weightlessness.

The new research showed that intracranial pressure in zero-gravity conditions, such as exists in space, is higher than when people are standing or sitting on Earth, but lower than when people are sleeping on Earth. The researcher’s finding suggests that the constancy of pressure on the back of the eye causes the vision problems astronauts experience over time.

More important, the research has also suggested a possible cure.

“The information from these studies is already leading to novel partnerships with companies to develop tools to simulate the upright posture in space while astronauts sleep, thereby normalizing the circadian variability in intracranial pressure, and hopefully eliminating the remodeling behind the eye,” said Dr. Levine, who holds the Distinguished Professorship in Exercise Sciences.

The researchers have continued studying whether it is possible to lower intracranial pressure by means of a vacuum device that pulls blood away from the head. They previously showed that a negative pressure box that snuggly fits the lower body can lower intracranial pressure when applied for 20-minute periods. They will soon be testing the effect of the lower body negative pressure device on eye remodeling when negative pressure is applied for eight-hour periods. “Astronauts are basically supine the entire time they are in space. The idea is that the astronauts would wear negative pressure clothing or a negative pressure device while they sleep, creating lower intracranial pressure for part of each 24 hours,” said first author Dr. Justin Lawley, Instructor in Internal Medicine at UT Southwestern and a researcher at the IEEM.

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Curiosity spots cracks formed from drying mud

5:27 pm

mud cracks on Mars?

As Curiosity moves across the dust-shrewn dune-filled flats at the base of Mt. Sharp it has recently taken images of surface rocks that have cracks resembling those found from drying mud.

Scientists used NASA’s Curiosity Mars rover in recent weeks to examine slabs of rock cross-hatched with shallow ridges that likely originated as cracks in drying mud. “Mud cracks are the most likely scenario here,” said Curiosity science team member Nathan Stein. He is a graduate student at Caltech in Pasadena, California, who led the investigation of a site called “Old Soaker,” on lower Mount Sharp, Mars.

If this interpretation holds up, these would be the first mud cracks — technically called desiccation cracks — confirmed by the Curiosity mission. They would be evidence that the ancient era when these sediments were deposited included some drying after wetter conditions. Curiosity has found evidence of ancient lakes in older, lower-lying rock layers and also in younger mudstone that is above Old Soaker.

The rover is no longer on the floor the crater, but in the foothills at the base of Mt. Sharp. Thus, what we are likely looking at is evidence of the slow disappearance of the giant lake that scientists think once filled Gale Crater. These mud cracks suggest that the rover is now moving up out of the lake and through its margins.

I plan to do a rover update for both Curiosity and Opportunity tomorrow, so stay tuned.

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Preparing to dive into Saturn’s rings

9:35 am

Saturn from above

Cool image time! The photo at the right, reduced to show here, was taken by Cassini on October 28, 2016 as it was shifting its orbit to prepare for the spacecraft’s last year at Saturn, where it will make repeated dives down past and even inside the gas giant’s rings. As they note at the link,

No Earth-based telescope could ever capture a view quite like this. Earth-based views can only show Saturn’s daylit side, from within about 25 degrees of Saturn’s equatorial plane. A spacecraft in orbit, like Cassini, can capture stunning scenes that would be impossible from our home planet.

It is interesting to compare this image with this July image. Comparing the two provides a sense of Cassini’s travels.

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NASA asteroid redirect mission delayed again

11:15 pm

Due to the uncertainty of its budget NASA has decided to delay the award of the contracts to begin work on its asteroid redirect mission (ARM).

The uncertainty is that Congress has never budgeted any real money for it. The mission was proposed by Obama but only vaguely, without any real support. First it was to be a manned mission to an asteroid, using Orion. Then it was to be an unmanned mission to bring a large asteroid closer to Earth to be later visited by astronauts in an Orion capsule. Then the large asteroid became a mere boulder, with the manned mission delayed until the unforeseen future.

I think NASA sees the writing on the wall here. They expect this vague unsupported mission to die with the next administration, and have decided it is better not to waste money on it now.

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The raging storms of Jupiter’s south pole

9:55 am

Cool image time! Below the fold I have embedded an animation that was assembled from 30 Juno images taken during its third orbital close approach of Jupiter. It is at first a little hard to watch, which is why I have not made it visible on the main page, but it is worth watching because it gives a real sense of how powerful and violent the storms are in the polar regions of the gas giant planet. Keep your eye especially glued to the storms near the center of the image. In a very short time that it took Juno to zip past Jupiter, less than a day, these storms rotated about one third. Remember too that each storm would probably cover at least half of the Earth’s surface.

We desperately need a fleet of weather satellites orbiting Jupiter to give us a continuous view of these storms. The knowledge gained about atmospheric weather patterns would be priceless.

» Read more

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Utah climate scientists whine about possible NASA cuts

9:31 am

The squealing of pigs: In the kind of journalistic pro-government spending propaganda that I despise, the Salt Lake Tribune today published this article giving climate scientists in their local area a platform to lobby the public in favor of their NASA funding.

The article provides a quick quote from a Trump campaign official noting their strong hostility to the politicization of climate research, and then spends the rest of the article allowing scientist after scientist to condemn that position and to defend that spending, repeatedly implying that should the NASA cuts go through, the research will end and even possibly that access to the data from NASA climate satellites will be denied to the public and to the scientists. At no time does the article provide any thoughtful information to explain that Trump administration perspective, which is based on some reasonable and very justifiable concerns.

I note this article as a warning. Expect more of this very bad journalism. Most of the press are blindly liberal and Democratic Party partisans. They are going to work blindly with the climate community to help them defend their funding, without the slightest effort at objective reporting. The public should be aware of this, and see this political lobbying for what it is.

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The status of telescopes the NSF is getting rid of

9:08 am

Back in 2012 the National Science Foundation (NSF) proposed that it cease funding a slew of older, smaller telescopes in order to use that money to fund the construction and operation of newer more advanced facilities. This article, focused on the fate of the Arecibo Observatory in Puerto Rico, provides a nice table that shows the status of these telescopes.

The options were either to find new funding, be mothballed, or even demolished. It appears that most of the telescopes in question have found new funding and will remain in use in some manner. The one telescope that has apparently failed to obtain any additional funding from others is the McMath–Pierce Solar Telescope on Kitt Peak in Arizona, which when built in 1962 was the world’s largest solar telescope, an honor for which it is still tied.

In 2015 I had written an article for Sky & Telescope about how these budget cuts were effecting the telescopes on Kitt Peak. At that time the people in charge of McMath-Pierce were hunting for new support but were coming up short. Almost two years later it appears that their hunt has been a failure, and the telescope will likely be shut down, and possibly demolished.

It will be a sad thing if McMath-Pierce is lost, but I am not arguing to save it. If its observational capabilities were truly valuable and needed by the scientific community than someone would have come forward to finance it. That no one has suggests that the money really can be spent more usefully in other ways.

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Could Tabby’s Star have eaten a planet?

8:50 am

A new theory has been proposed by astronomers to explain the unprecedented dimming of Tabby’s Star, and it isn’t an alien civilization.

If Tabby’s star devoured a planet in the past, the planet’s energy would have made the star temporarily brighten, then gradually dim to its original state. The bigger the planet was, the longer the star would take to dim. Depending on the size of the planet, this event could have happened anywhere between 200 and 10,000 years ago.

As the planet fell into its star, it could have been ripped apart or had its moons stripped away, leaving clouds of debris orbiting the star in eccentric orbits. Every time the debris passes between us and the star, it would block some light, making the star seem to blink.

If true, this theory would suggest that such events can happen more than scientists has expected. Moreover, this theory can be tested during future observations when the star experiences its next dimming.

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The sunspot crash continues

3:49 pm

On Sunday NOAA posted its monthly update of the solar cycle, covering sunspot activity for December. As I do every month, I am posting it here with annotations to give it context.

December 2016 Solar Cycle graph

January 2017 sunspots as of January 9, 2017

The graph above has been modified to show the predictions of the solar science community. The green curves show the community’s two original predictions from April 2007, with half the scientists predicting a very strong maximum and half predicting a weak one. The red curve is their revised May 2009 prediction.

Sunspot activity continues to decline, and it appears to be declining at a steadily faster rate as the solar cycle ramps down towards minimum. Not only did sunspot activity drop below the 2007 low prediction in 2016, since 2017 began the sun has been blank almost continuously, as shown by the graph on the right. The signs continue to point to a solar minimum occurring much sooner than predicted, producing an unprecedented short and weak solar cycle.

Despite this, the appearance in December of the first sunspot for the next solar cycle suggests that we will not be entering a Grand Minimum in the coming decades. It does not guarantee it, as there is some evidence that even though no sunspots were visible during the Maunder Minimum in the 1600s the magnetic activity that causes sunspots did continue, and with our better observation equipment today we may see sunspots they would not have seen in the 1600s.

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Herschel Crater on Mimas

10:00 am

Herschel Crater on Mimas

Cool image time! The photo on the right was taken by Cassini on October 22, 2016 when the spacecraft was about 115,000 miles away and has a resolution of about 3,300 feet per pixel. It highlights well Mimas’ most distinctive feature, its single gigantic crater, which also makes the tiny moon of Saturn one of the more distinctive planetary bodies in the entire solar system.

Named after the icy moon’s discoverer, astronomer William Herschel, the crater stretches 86 miles (139 kilometers) wide — almost one-third of the diameter of Mimas (246 miles or 396 kilometers) itself.

Large impact craters often have peaks in their center — see Tethys’ large crater Odysseus in The Crown of Tethys. Herschel’s peak stands nearly as tall as Mount Everest on Earth.

The mystery here is how did Mimas survive such an impact. One would think that the moon would be been split apart by the collision, and that it didn’t suggests the material involved was soft enough to absorb the dynamic forces, and that the speed of the impact was slow enough to reduce those forces overall.

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The Earth and Moon, as seen from Mars

1:00 pm

The Earth and Moon as seen from Mars

Cool image time! The image above, a composite of four separate Mars Reconnaissance Orbiter pictures, was taken on November 20, 2016.

Each was separately processed prior to combining them so that the moon is bright enough to see. The moon is much darker than Earth and would barely be visible at the same brightness scale as Earth. The combined view retains the correct sizes and positions of the two bodies relative to each other.

The reddish region on Earth is Australia, with Antarctica the bright white area below that.

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Hubble takes a look at both Voyagers’ interstellar path

10:43 am

Using the Hubble Space Telescope astronomers have taken a peek at the interstellar material that the two Voyager spacecraft will travel through as they move out and leave the solar system in the coming decades.

Voyager 1 is 13 billion miles from Earth, making it the farthest human-made object ever built. In about 40,000 years, after the spacecraft will no longer be operational and will not be able to gather new data, it will pass within 1.6 light-years of the star Gliese 445, in the constellation Camelopardalis. Its twin, Voyager 2, is 10.5 billion miles from Earth, and will pass 1.7 light-years from the star Ross 248 in about 40,000 years.

For the next 10 years, the Voyagers will be making measurements of interstellar material, magnetic fields, and cosmic rays along their trajectories. Hubble complements the Voyagers’ observations by gazing at two sight lines along each spacecraft’s path to map interstellar structure along their star-bound routes. Each sight line stretches several light-years to nearby stars. Sampling the light from those stars, Hubble’s Space Telescope Imaging Spectrograph measured how interstellar material absorbed some of the starlight, leaving telltale spectral fingerprints.

Hubble found that Voyager 2 will move out of the interstellar cloud that surrounds the solar system in a couple thousand years. The astronomers, based on Hubble data, predict that the spacecraft will spend 90,000 years in a second cloud before passing into a third interstellar cloud.

This is very clever science. It allows data from Hubble to complement the data from the two Voyager spacecraft to better understand the interstellar regions that surround our solar system.

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Could Venus’ atmospheric dark streaks be life? Mission proposes to find out

10:00 am

A clever mission concept, proposed as a joint Russian/U.S. unmanned probe to Venus, would use a solar-powered unmanned aerial vehicle (UAV) to fly through the atmosphere for at least a year in order to try to find out the nature of the planet’s atmospheric mysterious dark streaks.

Descending hypersonically into the atmosphere after detaching from the orbiter, the UAV would be filled with hydrogen or helium gas, keeping it buoyant at a nominal floating altitude of 50 kilometers, allowing it to glide through the clouds while moving through the night-time hemisphere. Upon daylight, the solar-powered propellors would kick in and raise the craft’s altitude to around 60 kilometers.

Over the course of three to four days, the craft could move around the planet along the upper atmosphere’s ‘super-rotation,’ the strange phenomenon where the atmosphere seems to be uncoupled from the solid planet and rotates much faster. The UAV would therefore be able to explore the clouds at different altitudes, moving from air mass to air mass, from regions with UV absorbers to regions devoid of them, sampling and measuring the composition of the atmosphere.

The dark streaks, first photographed when Mariner 10 flew past on February 5, 1974 and took more than four thousand pictures, are made of a still unknown material in the upper clouds that absorbs ultraviolet light. The scientists of this mission concept propose that these dark streaks could even be Venusian life.

Finding life at high altitude in the atmosphere of a planet would make sense. After all, microbes have been found at similar heights in Earth’s atmosphere. The challenge for life on Venus is the planet’s extreme temperature. The surface, at 462º C (864º F), is hot enough to melt lead, and the surface pressure of 92 bar is the equivalent of being almost a kilometer under water.

However, in a region beginning around 50 kilometers in altitude and extending a dozen kilometers outward is a sweet spot where the temperature ranges between 30ºC and 70ºC (86ºF to 158ºF) and the pressure is similar to Earth’s surface. Life could potentially survive in this zone where the dark-streaking UV absorber is found.

Intriguingly, the sulfuric acid droplets within the clouds aren’t necessarily a show-stopper to life. Earlier Venera missions detected elongated particles in the lower cloud layer that are about a micron long, about the width of a small bacterium. These particles could be coated in ring-shaped polymers of eight sulphur atoms, called S8 molecules, which are known to exist in Venus’ clouds and which are impervious to the corrosive effects of sulfuric acid. Furthermore, S8 absorbs ultraviolet light, re-radiating it in visible wavelengths. If the particles are microbes, they could have coated themselves in S8, making them resistant to the corrosive effects of sulfuric acid. It has even been postulated that the S8 exists as a result of microbial activity.

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Astronomers predict binary stellar merger in 2022

9:37 am

Astronomers are predicting that a two binary stars that orbit so close together that they share an atmosphere will merge and explode as a bright red nova in approximately five years.

According to the actual paper [pdf], they also predict that this will be a naked eye event, visible in the northern hemisphere.

Note that a red nova is not a supernova. These are different types of explosions, with the supernova many times more powerful and rare. Nonetheless, the event itself will spectacular, should the prediction be correct.

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Launch of joint NOAA/NASA weather satellite delayed again

7:48 pm

Bad timing for NASA’s climate program: The launch of the first Joint Polar Satellite System (JPSS-1), a project of both NOAA and NASA, has been delayed from March 2017 to at least July because of problems with one instrument as well as delays in completing the satellite’s ground systems.

“The main factors delaying the JPSS-1 launch are technical issues discovered during environmental testing of the satellite and the Advanced Technology Microwave Sounder (ATMS) instrument,” Leslie said in a statement. ATMS issues were also one of the reasons for the previous delay. In addition, he cited “challenges in the completion of the common ground system” that will be used for JPSS and other NOAA polar-orbiting weather satellites.

The latest decays prompted NOAA to seek financial relief for the program. A provision in the continuing resolution (CR) passed Dec. 9, which funds the federal government through late April at 2016 levels, gives NOAA the authority to spend at higher levels for the JPSS program.

The goal with the JPSS program was to combine NOAA weather satellites with NASA’s climate research satellites. The program however has had technical and budgetary problems, as this is not the first launch delay or cost overrun.. Moreover, the origins of the JPSS program came from a failed effort in the 1990s and 2000s [pdf] to combine NOAA, Defense Department, and NASA weather satellites under what was then called the NPOESS program. When that program was restructured in 2010 to become JPSS the Defense Department pulled out.

Considering the strong rumors now suggesting that the Trump administration plans to slash NASA’s climate budget while shifting the remains of the program to NOAA, this delay of JPSS-1 is an especially good example of bad timing. It provides the new administration strong ammunition for such proposed changes.

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Astronomers identify for the first time the source of a fast radio burst

7:25 pm

For the first time astronomers have pinned down the location of a fast radio burst (FRBs), short bursts lasting only seconds that were only discovered about a decade ago.

A dim dwarf galaxy 2.5 billion light years from Earth is sending out the mysterious millisecond-long blasts of radio waves, researchers report Wednesday in Nature and Astrophysical Journal Letters. The bursts traverse vast expanses of time and intergalactic space before reaching our planet. “This really is the first ironclad association of a fast radio burst with another astronomical source, so it’s a pretty huge result,” said Duncan Lorimer, an astronomer at West Virginia University who reported the first detection of a fast radio burst (FRB) in 2007.

The uncertainty of science: Only 18 FRBs have been identified since they were first discovered. Until now, it was unclear whether they occurred in our galaxy or beyond, though it was suspected they were coming from other galaxies. This discovery proves that. What remains unknown is what causes the burst, which signals an energy pulse equivalent to that of 500 million suns.

“I am not exaggerating when I say there are more models for what FRBs could be than there are FRBs,” said Cornell astronomer Shami Chatterjee, the lead author of the new Nature paper. Many scientists think the bursts are emitted by distant neutron stars, the super-dense embers of exploded suns. But some believe they must originate in our own galaxy. Still more suggest that FRBs could be caused by cataclysms like a supernova or a collision of two stars. This last theory was compelling because most FRB detections were one-off events — astronomers never spotted more than one flare from a single source.

Today’s announcement was made possible by the fact that the burst itself is repeating. In fact, it is the only FRB so far known to do so, which also means that what they learn about it might not be applicable to the other bursts.

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NASA approves two new asteroid missions

3:05 pm

NASA has approved two new unmanned missions aimed at studying the asteroids.

Lucy will take a close look at six Trojan asteroids orbiting near Jupiter, after first visiting a main belt asteroid.

Lucy, a robotic spacecraft, is scheduled to launch in October 2021. It’s slated to arrive at its first destination, a main belt asteroid, in 2025. From 2027 to 2033, Lucy will explore six Jupiter Trojan asteroids. These asteroids are trapped by Jupiter’s gravity in two swarms that share the planet’s orbit, one leading and one trailing Jupiter in its 12-year circuit around the sun. The Trojans are thought to be relics of a much earlier era in the history of the solar system, and may have formed far beyond Jupiter’s current orbit.

Psyche will visit 16 Psyche, an unusual metal-rich asteroid made up mostly of iron and nickel.

While Psyche will use an ion engine, allowing it great freedom and even the potential to go elsewhere, like Dawn, when its primary mission is complete, I have not been able to determine whether Lucy will use conventional chemical altitude thrusters or an ion-type engine.

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First sunspot for the next solar cycle spotted

11:42 am

Solar scientists have spotted the first sunspot on the Sun with a reversed polarity, meaning that it really belongs to the next sunspot cycle.

This is not unusual. The sunspots from different cycles routinely overlap by several years, with the sunspots from the old cycle moving close to the equator with time and the new cycle sunspots appearing at high latitudes. What this does suggest is that there will be sunspots after the upcoming solar minimum, rather than the beginning of a new Grand Minimum with no sunspots for decades.

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Curiosity looks at Mount Sharp

9:06 am

Looking at Mount Sharp

Cool image time! During the ten day holiday period, during which the Curiosity science and engineering teams generally got a break, they programmed the rover to take a variety of observations over the entire period. Some of those observations included repeated snapshots of the view ahead, using the rover’s navigation camera. The image above, reduced slightly from the full resolution image to show here, is one example of that view.

You can see the dark sandy dune region in the foreground, and the increasing steepness of the slope in the background. What I find most interesting are what look like canyon washes flowing downhill on the right, in what appear to be diagonally parallel cuts. That they do not flow directly downhill suggest to me that they were not created by water flow but by wind erosion, though it is possible that the geology of different bedding plains could have forced the flows in a diagonal direction down the slope. If wind erosion is the cause, however, it suggests a process that took a very long time to occur, as the atmosphere of Mars is so thin.

The route the rover will take is through a much larger canyon slightly off camera to the right. While the slope up the mountain on the left of the image appears to be an easier route, the geology there is not as interesting. Note also that we are not looking at the peak of Mount Sharp, which is much farther south and far higher.

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