Tag: science

Mercury’s transit today

8:50 am

Here are a few links on today’s transit of the Sun by Mercury, which is going on right now.

I could give more, but this event is hardly as important as many new media are saying. It is interesting, and rare, and important in that it helps scientists get a better understanding of the uncertainties in their exoplanet research, but hardly important scientifically.

Consider this however: Mercury’s real orbit has it circle the sun every 88 days. If we could only detect it by the transits seen from Earth, we would only see it cross the Sun in 2006, 2016, 2019, and 2032. Figuring out its real orbit from that data would likely be impossible. Now, I realize that these seemingly random transits are partly determined by the Earth’s own orbit around the Sun, but they still illustrate that our use of transits to detect and characterize exoplanets has its limits. And in science one must always be aware of one’s limits.

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A review of Al Gore’s movie “An Inconvenient Truth”, ten years later

12:29 pm

climate data showing pause in warming since 1998

The uncertainty of science: A new review of Al Gore’s movie “An Inconvenient Truth”, ten years later after its release, looks closely at the predictions the film made to see if they have come true, or were at least pointed in an accurate direction.

Guess what? The film’s predictions have turned out to be generally wrong. From predicting an ice-free Arctic to a snow-free Mt. Kilimanjaro to more extreme weather to a continuing warming as carbon dioxide increased, Gore’s predictions have each failed.

I especially like the last one, that as carbon dioxide rose the temperatures would rise in lockstep, as predicted by all climate models. The article notes that temperatures have not done so, that the global climate temperature has been practically unchanged since 1998, and backs up this point with a paper published by the science journal Nature.

The graph above is from that paper. The black line that rises above the red, blue, and gold lines is one of the more respected climate models. The other lines are from the actual data. As you can see, the climate model fails to predict the climate, meaning that the theory used to create it is incomplete or inaccurate.

This is not to say that the theory might not be true. Global warming, initiated by the increase in carbon dioxide in the atmosphere, might very well happen. The data shows however that the climate scientists touting this theory do not yet understand the Earth’s complex global climate well enough to prove their theory true. There are other factors influencing the climate they have not yet recognized, factors such as the Sun’s variability and the fact that CO2 by itself is a actually a trace gas and not the atmosphere’s chief global warming component, which is water.

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Global elevation map of Mercury

8:39 am

The science team for Messenger have now released a new digital elevation model of Mercury’s global surface.

The new product reveals a variety of interesting topographic features, as shown in the animation above, including the highest and lowest points on the planet. The highest elevation on Mercury is at 4.48 kilometers [2.78 miles] above Mercury’s average elevation, located just south of the equator in some of Mercury’s oldest terrain. The lowest elevation, at 5.38 kilometers [3.34 miles] below Mercury’s average, is found on the floor of Rachmaninoff basin, a basin suspected to host some of the most recent volcanic deposits on the planet.

If you watch the animation at the link, you will notice that the high points tend to cluster in the lower latitudes, while the low points tend to favor the high latitudes, suggesting a very slightly bulged shape, which is not surprising considering Mercury’s close proximity to the Sun.

The data release today also included an additional map showing the known geological features in more detail.

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New jellyfish spotted at 2 miles depth

2:04 pm

A NOAA mapping robot working two miles beneath the ocean surface recently captured video of a species of jellyfish previously unknown.

The newly discovered jellyfish has two sets of tentacles, short and long. When the the long tentacles are even and extended outward, and the bell is motionless, this could mean it’s readying to ambush its prey, scientists speculate. Inside the bell, red radial canals connect what scientists say looks like the bright yellow gonads.

I have posted the video below the fold.
» Read more

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Pluto’s solar wind interaction more like a planet’s

9:11 am

Data from New Horizons has found that Pluto, in its interaction with the solar wind, behaves more like a planet than a comet.

Previously, most researchers thought that Pluto was characterized more like a comet, which has a large region of gentle slowing of the solar wind, as opposed to the abrupt diversion solar wind encounters at a planet like Mars or Venus. Instead, like a car that’s part gas- and part battery-powered, Pluto is a hybrid, the researchers say. “This is an intermediate interaction, a completely new type. It’s not comet-like, and it’s not planet-like. It’s in-between,” McComas said. “We’ve now visited all nine of the classical planets and examined all their solar wind interactions, and we’ve never seen anything like this.”

…Pluto continues to confound. Since it’s so far from the sun – an average of about 5.9 billion kilometers (3.7 billion miles) – and because it’s so small, scientists thought Pluto’s gravity would not be strong enough to hold heavy ions in its extended atmosphere. But, “Pluto’s gravity clearly is enough to keep material sufficiently confined,” McComas said. Further, the scientists found that very little of Pluto’s atmosphere is comprised of neutral particles converted to electrically charged ions and swept out into space.

As I’ve written previously, we simply don’t know enough yet about planets to come up with a reasonable definition. As far as I’m concerned, Pluto will remain a planet until we do.

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Ice and volcanoes on ancient Mars?

1:03 pm

New data of past volcanic activity on Mars suggest that the red planet was once covered by at least one extensive ice sheet.

There is a great deal of uncertainty in this conclusion, however. They have found one example with the right geology to suggest past ice sheets under which volcanoes erupted. Translating this into an extensive ice sheet requires many assumptions that might not prove true with further research.

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Exoplanets found nearby

5:26 pm

Worlds without end: Astronomers have identified three planets close to the habitable zone on a star only 39 light years away.

A year on the two inner planets lasts just a couple of days. Data on the third world are sparse; it could take anywhere between 4.5 and 72.8 days to trek around its sun. The star, designated 2MASS J23062928−0502285, is roughly the size of Jupiter — about one-tenth as wide as our sun — and about 3,200 degrees Celsius cooler than the sun. Such runts make up about 15 percent of the stars in the galaxy, though astronomers had not found planets around one before. All three planets were discovered as periodic dips in starlight in late 2015 using TRAPPIST, a telescope at La Silla Observatory in Chile.

If anything does crawl or grow on these worlds, it bathes in mostly infrared light. The innermost planets receive several times as much energy from their star as Earth does from our sun, which technically puts them outside the star’s habitable zone (SN: 4/30/16, p. 36). But the planets are huddled up so close to the star that gravity might keep them from spinning, creating a temperate zone along the line where day turns to night, the researchers suggest.

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Russia and Europe agree to delay next ExoMars mission

5:22 pm

After looking at their schedules the Russians and Europeans have agreed that they cannot meet the schedule to launch the second ExoMars mission by the next launch window in 2018, and have agreed to delay the mission until 2020.

This really isn’t a surprise, since Russia was a late replacement of the U.S. when the Obama administration backed out of the project suddenly. They need time to prepare.

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The depressed heart of Pluto

9:29 am

Using elevation data gathered by New Horizons during its fly-by of Pluto last year scientists have created an elevation map of the heart-shaped Sputnik Planum that shows that its central region is on average two miles deeper than the surrounding terrain.

The data even shows giant blocks of frozen water floating on the denser nitrogen ice.

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Boiling water on Mars

9:06 am

Scientists now think that the dark streaks they see seasonally develop on Martian slopes are caused when frozen underground water brine is exposed to the atmosphere so that the water boils off, leaving the salt.

More here, including videos of their Earthbound experiments. On Earth, the boiling water caused avalanches and streaks, but because of the higher gravity they were not as long.

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Halo craters on Pluto

4:48 pm

More images from New Horizons reveal even more strange terrain on Pluto.

Data suggest that the bright rims are made of methane ice, while the dark crater floors are made of water ice, though why this has happened is a complete mystery. As they note at the link above, “Exactly why the bright methane ice settles on these crater rims and walls is a mystery; also puzzling is why this same effect doesn’t occur broadly across Pluto.”

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New research confirms CO2 increase is greening Earth

9:11 am

The uncertainty of science: New data from satellites have confirmed that the increase in carbon dioxide in the atmosphere in the past century is contributing to an expansion of plant life globally.

Researchers studying NASA satellite data on the Earth’s vegetation coverage have discovered that plants have significantly increased their leaf cover over the last 35 years to the point that new growth across the planet is equivalent to an area twice as large as the continental United States. According to the study, the largest contributor to this greening is the growing level of carbon dioxide (CO2) in the atmosphere.

Using data collected from instruments such as NASA’s Moderate Resolution Imaging Spectrometer mounted on the AquaProbe satellite and the National Oceanic and Atmospheric Administration’s Advanced Very High Resolution Radiometer (such as that deployed on NOAA’s DSCOVR satellite), an international team of researchers has determined that CO2 fertilization explains fully 70 percent of the greening effect observed.

I love how the article repeatedly inserts several out-of-context comments about the dangers of global warming, even though everything in the story suggests that global warming might actually be beneficial.

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Venus’s dark stripes remain unexplained

9:50 am

The uncertainty of science: A new analysis of past data from Venus suggests that the planet’s atmospheric sulfur cannot be causing the atmosphere’s dark stripes seen in the ultraviolet.

If we look at Venus in a normal optical telescope, we see only a dull yellowish-white sphere without any other distinguishing features. However, if we capture an image in the ultraviolet range, the picture changes drastically – dark and light areas appear on the disc, reflecting the dynamics of the atmosphere. “These areas mean that somewhere in the upper cloud layer there is a substance that is absorbing UV radiation. Over the past 30 years there have been a wide range of hypotheses as to what this substance could be. Many scientists believed that sulfur particles were responsible for the absorption. But now we will have to abandon this hypothesis,” says Krasnopolsky.

It appears that the new analysis puts the sulfur too low in the atmosphere.

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Curiosity drills again

9:24 am

The Curiosity science team has paused the rover’s journey up Mt Sharp in order to drill another hole, this time on the fractured rock covering the surface of Naukluft plateau.

The drill effort was a success, and they are now gathering data from the hole and the material from it. At the same time, the drilling process drained the rover’s batteries, which means they are now taking a break from science to let them recharge.

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The methane seas of Titan

10:23 am

Scientists have used the data that Cassini has gathered in more than a hundred fly-bys of Titan to assemble a rough outline of the geology and make-up of Titan’s liquid lakes.

There are three large seas, all close to the north pole, surrounded by dozens of smaller lakes in the northern hemisphere. Just one lake has been found in the southern hemisphere. The exact make-up of these liquid reservoirs remained elusive until recently. A new study using scans from Cassini’s radar during flybys of Titan between 2007 and 2015 confirms that one of the largest seas on the moon, Ligeia Mare, is mostly liquid methane.

“We expected to find that Ligeia Mare would be mostly ethane, which is produced in abundance in the atmosphere when sunlight breaks methane molecules apart,” explains Alice Le Gall from the Laboratoire Atmosphères, Milieux, Observations Spatiales and Université Versailles Saint-Quentin, France, and lead author of the new study. “Instead, this sea is predominantly made of pure methane.”

The data is also giving them the first understanding of the weather and geology that forms the lakes, including why methane instead of ethane dominates.

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Hubble discovers moon circling Kuiper belt object

10:10 am

Worlds without end: Hubble has spotted a small moon orbiting the distant Kuiper Belt object Makemake.

The moon — provisionally designated S/2015 (136472) 1 and nicknamed MK 2 — is more than 1,300 times fainter than Makemake. MK 2 was seen approximately 13,000 miles from the dwarf planet, and its diameter is estimated to be 100 miles across. Makemake is 870 miles wide. The dwarf planet, discovered in 2005, is named for a creation deity of the Rapa Nui people of Easter Island.

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An extended Dawn mission might go to another asteroid

10:05 am

The Dawn science team is proposing that NASA extend the mission by allowing them to use the remaining fuel on the spacecraft to send it away from Ceres and towards another asteroid.

Originally mission managers had planned to park it in a stable orbit around Ceres later this summer, creating a permanent artificial satellite. They could not crash the spacecraft into Ceres, as is customary with many similar missions, because Dawn has not been sterilized in accord with planetary protection procedures. But the extra xenon has created an additional opportunity.

Scientists involved with the spacecraft say they could visit a third object in the asteroid belt. “Instead, we want to go the other way, away from Ceres, to visit yet another target,” principal investigator Chris Russell told New Scientist. Russell would not name the destination without approval of the plan from NASA, but we should learn about it in a few months.

Up until now they had said that they didn’t have enough remaining fuel to do much more than remain in orbit at Ceres. It appears now that they have saved enough fuel to give them more options.

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New Hubble image of Red Rectangle

9:13 am

The Red Rectangle

Cool image time! I think the Red Rectangle might be my favorite planetary nebula. The new image on the right, taken by the Hubble Space Telescope, is the best yet of this weirdly shaped object. And it continues to suggest, as I noted whimsically in an article about it for Sky & Telescope back in November 2014, that this is a web being spin by the universe’s largest spider.

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New images of failed Beagle 2 on Mars

9:02 am

By carefully improving the resolution of images taken by Mars Reconnaissance Orbiter of the landing site of the 2003 European Mars lander Beagle 2, scientists think the lander might have successfully landed but failed to deploy its solar shields completely.

Showing a bright blip in dusty terrain, the new picture is four times the resolution of previous images. The image adds weight to the theory that the diminutive spacecraft – just under a metre in diameter – landed as planned on Mars in 2003, but failed to fully unfurl its solar panels. “Given the size of Beagle 2, even with super-resolution images you are not likely to see more than a series of blobs because it is so small,” said Mark Sims, of the University of Leicester and former mission manager for Beagle 2. “What it does show is that it is on the surface and it is at least partially deployed.”

The technique they have developed for improving image resolution will also be useful to tease out new details about the Martian surface.

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Fake images in biology research papers

9:38 am

The uncertainty of peer review: A new study has found that since 1995 as many as 5.5% of all biomedical research papers per year contain duplicate or faked images.

Bik, who is at Stanford University in California, spent two years looking at articles published from 1995 to 2014 in 40 different journals, hunting for instances in which identical images were used to represent different experiments within the same paper. She cross-checked the duplications that she found with her two co-authors, both microbiologists.

Overall, 4% of the inspected papers contained such images, the researchers found. But rates ranged from over 12% in the International Journal of Oncology, to 0.3% in the Journal of Cell Biology, which has since 2002 systematically scanned images in its accepted papers before publication. Journals with higher impact factors generally had lower rates of duplicated images.

…Many of the problems were probably sloppy mistakes where people selected the wrong photograph, says Bik. But half or more look deliberate — because images are flipped or rotated or the same features occur twice in the same photograph. [emphasis mine]

Essentially, a significant number of scientists in medical research are purposely faking data.

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Evidence of water on Ceres?

9:21 am

water on Ceres?

New data from Dawn suggests that there is significant water locked in surface of Ceres’s north polar regions.

These data reflect the concentration of hydrogen in the upper yard (or meter) of regolith, the loose surface material on Ceres. The color information is based on the number of neutrons detected per second by GRaND. Counts decrease with increasing hydrogen concentration. The color scale of the map is from blue (lowest neutron count) to red (highest neutron count). Lower neutron counts near the pole suggest the presence of water ice within about a yard (meter) of the surface at high latitudes.

Note that the data has not detected water. The blue areas on the image to the right suggest an increased amount of hydrogen, which could only be held to the surface if it was locked in some molecule, with water being the most likely candidate. Like the Moon, until we actual capture some samples, it will be difficult to confirm with certainty the presence of water.

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China grows mouse embryos in space

10:51 am

During a two week unmanned biology satellite mission, Chinese scientists successfully demonstrated that mouse embryos can develop in weightlessness.

The team developed an embryo culture system and placed it within a small enclosed chamber [on the spacecraft] that provides the ideal conditions for the embryos to develop in space. While the chamber was in orbit, a camera attached to the experiment took photographs of the embryos as they developed in microgravity, and sent these images back to Earth. With the aid of their imaging technology, the researchers were able to observe how the mammalian two-cell stage embryos developed into blastocysts under microgravity after four days. Blastocysts are structures formed in the very early development of mammals. In humans blastocysts begin to form five days after fertilization.

The researchers will now compare their space-developed embryos to those cultured in normal laboratory environments on Earth to see what differences there are between the two at both a cellular and molecular level.

None of this proves that life can be conceived and grow in weightlessness. It does however suggest that it might be possible.

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Liver damage from weightlessness?

11:28 pm

The uncertainty of science: Mice flown for almost two weeks on the last space shuttle mission in 2011 have shown evidence of the early symptoms of liver disease.

The mice spent time orbiting the Earth on the final space shuttle flight in 2011. Once they returned home, teams of scientists were allowed to share and study their internal organs.

Jonscher’s team found that spaceflight resulted in increased fat storage in the liver, comparing pair-fed mice on Earth to those on the shuttle. This was accompanied by a loss of retinol, an animal form of Vitamin A, and changes to levels of genes responsible for breaking down fats. As a result, mice showed signs of nonalcoholic fatty liver disease (NAFLD) and potential early indicators for the beginnings of fibrosis, which can be one of the more progressive consequences of NAFLD. “It generally takes a long time, months to years, to induce fibrosis in mice, even when eating an unhealthy diet,” Jonscher said. “If a mouse is showing nascent signs of fibrosis without a change in diet after 13 ½ days, what is happening to the humans?”

This result doesn’t prove that weightlessness causes liver damage. It only suggests that more research is needed, though the data from six month to year long missions suggest that the liver harm to humans is either non-existent or temporary.

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Problems with attitude system doomed Hitomi

12:48 am

A series of failures in the attitude system on Japan’s X-ray space telescope Hitomi led to its destruction.

The problem started when the satellite’s inertial reference unit detected Hitomi was rotating around its Z-axis at 21.7 degrees per hour. The spacecraft was actually stable at the time, mission managers from the Japan Aerospace Exploration Agency said Friday. The satellite’s attitude control system commanded Hitomi’s reaction wheels, rapidly-spinning devices which control the pointing of the spacecraft with momentum, to counteract the spin. The action caused the satellite to rotate in the opposite direction as the faulty inertial reference unit indicated, officials said. Momentum accumulated inside the reaction wheel system, and magnetic torquers aboard the satellite were unable to unload the building momentum, which neared the reaction wheels’ design limit.

Hitomi’s computers recognized the dangerous situation and put the satellite into safe hold a few hours later. The satellite tried to stabilize using the craft’s hydrazine-fueled rocket thrusters to aim its solar panels toward the sun. But the trouble was not over, and the spacecraft’s solar sensor was unable to find the sun. Struggling to correct the growing spin rate, small rocket firings inadvertently caused Hitomi to rotate faster due to a bad setting in the thruster system, JAXA officials said.

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Tetanus boosters can work for almost thirty years

9:17 am

The uncertainty of science: A new study has found that tetanus vaccine booster shots might last three times longer than previously believed.

The study looked for tetanus antibodies in 546 adults who had received the tetanus vaccine at some point in the past. Of those 546 adults, the researchers found that 97 percent still had sufficient antibodies to fight off tetanus. Since tetanus boosters are also designed to fight diphtheria, the same percentage also had antibodies to fight off that disease.

The researchers then looked at the amount of antibodies present in each individual compared to the amount of time that had passed since they received their vaccines. The result was that the study determined the half-life of a tetanus booster to be about 14 years, which means that the average person should be able to go about 28 years between boosters, or almost three times as long as the current CDC recommendation.

The half-life for diphtheria immunity was found to be even longer, at about 27 years, or roughly 54 years between boosters.

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An update on Philae

8:21 am

Link here. No big news. The lander remains silent, and has not yet been precisely located on the surface, though they have a pretty good idea where it is. They expect to get images of it on the surface sometime before September, when Rosetta’s mission will end with its own attempted touchdown on Comet 67P/C-G.

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The asteroid didn’t do it all

12:34 am

The uncertainty of science: A new study adds weight to the theory that the dinosaurs were already in decline when the asteroid hit 65 million years ago.

While some have argued that dinosaurs began petering out some 5 million or 10 million years before their final doom, the new paper suggests it started happening much earlier, maybe 50 million years before the asteroid catastrophe. In terms of species, “they were going extinct faster than they could replace themselves,” said paleontologist Manabu Sakamoto of the University of Reading in England. He led a team of British scientists who analyzed three large dinosaur family trees, looking for evidence of when extinctions began to outnumber the appearances of new species.

They found that starting to happen about 50 million years before the asteroid for most groups of dinosaurs. Two other groups showed increases rather than declines; if their results are included, the overall time for the start of dinosaur decline shrinks to 24 million years before the final demise.

I wrote a science article on this subject back in 1999, and even then the science was far from settled, with most paleontologists strongly arguing that the asteroid was only the final blow and that many other factors, including the big volcano eruption in India about that time, also contributed to the dinosaur’s extinction. That journalists and the planetary science community have pushed the asteroid as the sole factor in that extinction has been a disservice to science. The science has never been that certain.

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