Tag: science

Largest ancient meteorite impact found?

9:13 am

The uncertainty of science: Scientists doing geothermal research in Australia have discovered evidence of what they think is the largest known impact zone from an meteorite on Earth.

The zone is thought to be about 250 miles across, and suggests the bolide split in two pieces each about 6 miles across before impact. The uncertainty is that the evidence for this impact is quite tentative:

The exact date of the impacts remains unclear. The surrounding rocks are 300 to 600 million years old, but evidence of the type left by other meteorite strikes is lacking. For example, a large meteorite strike 66 million years ago sent up a plume of ash which is found as a layer of sediment in rocks around the world. The plume is thought to have led to the extinction of a large proportion of the life on the planet, including many dinosaur species.

However, a similar layer has not been found in sediments around 300 million years old, Dr Glikson said. “It’s a mystery – we can’t find an extinction event that matches these collisions. I have a suspicion the impact could be older than 300 million years,” he said.

In other words, they find some evidence that an impact occurred, but not other evidence that is expected to be found with such an impact. Moreover, the rocks at the sedimentary layer where the impact is found are dated around 300 million years ago, a time when no major extinction took place. Either this impact didn’t really happen, or it didn’t happen when it appears it should have, or it shows that large impacts don’t necessarily cause mass extinctions.

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Want to help name Pluto’s features? You can!

11:10 am

The New Horizons science team is asking the public to help name the planet’s features it expects to see when the spacecraft flies past Pluto on July 14.

I should mention that the project scientist for New Horizons is Alan Stern, who also happened to be a major player in the private space effort called Uwingu, which previously offered the public the opportunity to name features on Mars, without IAU approval.

In the case of New Horizons, Stern is kind of forced to work with the IAU, since the project is funded by NASA and NASA would never challenge a fellow bureaucracy like IAU.

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Did the Moon’s axis shift 3.5 billion years ago?

9:13 am

The uncertainty of science: Because the concentrations of ice on the moon are thought to be located on opposite sides of the planet, both locations 5.5 degrees away from the poles, a team of scientists has proposed that these locations were once the Moon’s poles and that the axis got shifted 3.5 billion years ago when a gigantic volcanic hotspot on the surface erupted.

He and his colleagues assumed that when the ice was deposited, it was centered on the poles. But what kind of event could have moved the poles by 5.5°? Known asteroid impacts were too small or in the wrong location to do the job. Instead, the team hypothesizes that a 3.5-billion-year-old hot spot could have nudged the poles to their present-day position. Pouring out enormous amounts of lava, that hot spot created Oceanus Procellarum, the vast dark spot on the near side of the moon. The Procellarum region is known to have high concentrations of radioactive elements that would have been hot in ancient times. The research team theorizes that this heat would have created a less dense lens in the moon’s mantle that would have caused the axis to wobble into today’s position.

This theory requires that the Moon’s ice is at least this old, which is quite a stretch. Also, if the Procellarum eruption caused a pole shift, I wonder why the other large lunar eruptions, which created the Moon’s other mare, did not shift the poles further and in other directions.

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Rosetta’s first attempt to contact Philae ends with no contact

8:59 am

After eight days of sending signals, listening for Philae, and getting no response, Rosetta has ceased its effort.

“It was a very early attempt; we will repeat this process until we receive a response from Philae,” says DLR Project Manager Stephan Ulamec. “We have to be patient.” On 20 March 2015 at 05:00 CET, the communication unit on the Rosetta orbiter was switched off. Now, the DLR team is calculating when the next favourable alignment between the orbiter and the lander will occur, and will then listen again for a signal from Philae. The next chance to receive a signal from the lander is expected to occur during the first half of April.

They always knew that it was unlikely for the lander to come alive this soon, but they tried anyway. The odds improve, however, in the coming months.

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An iron rain fell on Earth early in its formation

9:35 am

New research attempting to explain why the Earth but not the Moon has so much iron splattered through its mantle has found that iron can be more easily vaporized during impacts than previously thought, and thus rained down on the planet during the early asteroid bombardment.

Principal investigator Kraus said, “Because planetary scientists always thought it was difficult to vaporize iron, they never thought of vaporization as an important process during the formation of the Earth and its core. But with our experiments, we showed that it’s very easy to impact-vaporize iron.” He continued, “This changes the way we think of planet formation, in that instead of core formation occurring by iron sinking down to the growing Earth’s core in large blobs (technically called diapirs), that iron was vaporized, spread out in a plume over the surface of the Earth and rained out as small droplets. The small iron droplets mixed easily with the mantle, which changes our interpretation of the geochemical data we use to date the timing of Earth’s core formation.”

The Moon’s gravity in turn wasn’t sufficient to pull its own iron vapor down. Thus, it does not have much iron in its mantle.

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New evidence of child-smuggling in ancient Mayan human sacrifices

4:58 pm

Isotope testing of the teeth of the skeletons of children found in a cave in Belize has found that none had come from that region, suggesting that the children were kidnapped from other neighboring communities before they were sacrificed to the Mayan gods.

Though the data is still being crunched (the full report will be published when Lorenz presents her thesis later this year), initial analysis indicates that the children whose bones littered the Midnight Terror Cave did not come from the surrounding Upper Roaring River Valley, where the cave is located, or even from Belize. In fact, the young victims appear to have been brought to this spot from as far as 200 miles away (an enormous distance in the 9th century), before being taken deep into the earth to have their beating hearts cut from their chests to appease any number of angry gods.

The article is fascinating not only for the profound archeological discoveries it documents but also for its detailed description of the science process itself. It also is brutally honest. Even though these results cast a poor light on ancient Indian culture, something that is very political incorrect in today’s world, the author minces no words, even if he does wring his hands a bit about these conclusions.

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Water ice volcanoes on Ceres

2:12 pm

Data collected by Dawn since it entered orbit around Ceres on March 6 now strongly suggests that the bright spots on the surface are produced by venting water,

Andreas Nathues, principal investigator for Dawn’s framing camera, says the feature has spectral characteristics that are consistent with ice. Intriguingly, the brightness can be seen even when the spacecraft is looking on edge at the crater rim, suggesting that the feature may be outgassing water vapor above the rim and into space. “Ceres seems to be indeed active,” he says. The feature brightens through the course of the day, and then shuts down at night. Nathues says the behavior is similar to that of comets.

More here. By mid-April Dawn should finally settle this with high resolution images.

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New results from Messenger at Mercury

12:53 pm

Hollows on Mercury

As Messenger nears the end of its lifespan orbiting Mercury, the project scientists have put together a slate of talks on what they have learned, presented today at the 46th annual Lunar and Planetary Science Conference in Houston.

The images that go with these presentations can be found here.

The image on the right is a close-up of the mysterious and unexpected hollows that Messenger found scattered everywhere on Mercury’s surface. According to today’s presentation, scientists now believe they are very recent features, formed when material with a lower boiling point evaporated away because of Mercury’s harsh and very hot environment. Imagine for example a vein of dry ice in a rock crack. The temperature rises above freezing and the dry ice evaporates. And like the convection bubbles in tomato sauce as it simmers, some of that evaporation pushes its way up by popping out a bubble and leaving behind a hollow.

In the case of Mercury the material is likely not dry ice, though scientists as yet are unsure what it is.

They are also presenting talks on magnesium on Mercury, the planet’s many scarps, and detailed observations of the permanently shadowed polar craters that might have water-ice in them.

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New areas of Comet 67P/C-G come out of the shadows

8:56 am

Comet 67P/C-G's smaller lobe

Rosetta has snapped a new image of Comet 67P/C-G’s smaller lobe that not only shows the increased activity around the nucleus but captures areas of the comet that had formally been in darkness. The image also includes the region where engineers think Philae landed, which I think is the area just below the brightest flat area in the center of the lobe. That this area is now in daylight is why engineers are hopeful that Philae might soon wake up.

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Sloppy biosafety procedures found at federal disease center

8:43 am

Does this make you feel safer? An investigation of a federal center for studying dangerous diseases in primates has found serious biosafety procedure violations.

Concerns arose at the center in Covington, Louisiana, after two rhesus macaques became ill in late November with melioidosis, a disease caused by the tropical bacterium Burkholderia pseudomallei. In January, the U.S. Centers for Disease Control and Prevention (CDC) and Department of Agriculture investigators traced the strain infecting the primates to a vaccine research lab working with mice. Last month, as the investigation continued, CDC suspended the primate center’s 10 or so research projects involving B. pseudomallei and other select agents (a list of dangerous bacteria, viruses, and toxins that are tightly regulated). Meanwhile, a report in USA Today suggested the bacterium might have contaminated the center’s soil or water.

…In addition, workers “frequently entered the select agent lab without appropriate protective clothing,” the release says. No center staff has shown signs of illness. On 12 March, however, Tulane announced that blood tests have found that one worker has low levels of antibodies to the bacterium, suggesting possible exposure at the center, according to ABC News.

Is there any area of government expertise that isn’t screwing up royally these days? As far as I can tell, the answer is no. The sooner we as a people can cut back on the government’s resources so that they won’t have the ability to do us harm, the better off we will be.

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Curiosity moves on

9:18 am

After six months and a short pause in work while engineers analyzed a short circuit, Curiosity has finally left the Pahrump Hills are on the slopes of Mount Sharp.

The rover has begun driving away from the Pahrump Hills outcrop where it had spent the last six months. On Thursday, March 12, it drove about 33 feet (about 10 meters) southwestward. The rover team plans on taking Curiosity through a valley called “Artist’s Drive” to reach higher geological layers of Mount Sharp. Curiosity is currently heading towards a rock outcrop known as “Garden City.”

The link has a nice image showing Curiosity’s recent travels as well as its future route.

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Magnetic field science satellites launched

9:26 am

An Atlas 5 rocket successfully launched four NASA research satellites Thursday night designed to study the behavior of the Earth and Sun’s magnetic fields at high resolution.

The quartet of observatories is being placed into an oblong orbit stretching tens of thousands of miles into the magnetosphere — nearly halfway to the moon at one point. They will fly in pyramid formation, between 6 miles and 250 miles apart, to provide 3-D views of magnetic reconnection on the smallest of scales.

Magnetic reconnection is what happens when magnetic fields like those around Earth and the sun come together, break apart, then come together again, releasing vast energy. This repeated process drives the aurora, as well as solar storms that can disrupt communications and power on Earth. Data from this two-year mission should help scientists better understand so-called space weather.

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The neck of Comet 67P/C-G in color

9:16 am

The neck of Comet 67P/C-G

Rosetta’s high resolution camera has taken a color image of Comet 67P/C-G’s narrow neck, the area where the most plume activity has taken place.

When seen with the human eye, comet 67P/Churyumov-Gerasimenko is grey – all over. With its color filters Rosetta’s scientific imaging system OSIRIS, however, can discern tiny differences in reflectivity. To this effect, scientists from the OSIRIS team image the same region on the comet’s surface using different color filters. If, for example, the region appears especially bright in one of these images, it reflects light of this wavelength especially well.

“Even though the color variations on 67P’s surface are minute, they can give us important clues”, says OSIRIS Principal Investigator Holger Sierks from the Max Planck Institute for Solar System Research (MPS) in Germany. In a recent analysis performed by the OSIRIS team, the Hapi region clearly stands out from the rest of the comet: while most parts of 67P display a slightly reddish reflectivity spectrum as is common for cometary nuclei and other primitive bodies, the reflection of red light is somewhat lower in this region.

They as yet do not know exactly why the smooth area at the neck has a very slight blueish tinge, though they suspect it is because of the presence of a higher percentage of frozen water.

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Yutu reveals a complex lunar geology

6:56 pm

The uncertainty of science: The Chinese lunar rover Yutu has uncovered a much more complicated geology history than previously predicted at its landing site on the moon.

Those data paint a detailed portrait of the Chang’e 3 landing site, which sits just 165 feet (50 m) away from a 1,475-foot-wide (450 m) crater known as C1. C1 was gouged out by a cosmic impact that occurred sometime between 80 million and 27 million years ago, the study authors said.

Yutu studied the ground it rolled over, characterized the craters it cruised past and investigated an oddly coarse-textured rock dubbed Loong, which measures about 13 feet long by 5 feet high (4 by 1.5 m). Overall, the rover’s observations suggest that the composition of its landing site is quite different from that of the places visited by NASA’s Apollo missions and the Soviet Union’s Luna program.

The rover found 9 distinct layers, suggesting numerous and different past events that layered the surface.

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Ganymede’s underground salt water ocean

9:33 am

By measuring the interaction of Jupiter and Ganymede’s magnetic fields, scientists have been able to estimate the size of the salt water ocean in Ganymede’s interior.

A team of scientists led by Joachim Saur of the University of Cologne in Germany came up with the idea of using Hubble to learn more about the inside of the moon. “I was always brainstorming how we could use a telescope in other ways,” said Saur. “Is there a way you could use a telescope to look inside a planetary body? Then I thought, the aurorae! Because aurorae are controlled by the magnetic field, if you observe the aurorae in an appropriate way, you learn something about the magnetic field. If you know the magnetic field, then you know something about the moon’s interior.”

If a saltwater ocean were present, Jupiter’s magnetic field would create a secondary magnetic field in the ocean that would counter Jupiter’s field. This “magnetic friction” would suppress the rocking of the aurorae. This ocean fights Jupiter’s magnetic field so strongly that it reduces the rocking of the aurorae to 2 degrees, instead of 6 degrees if the ocean were not present. Scientists estimate the ocean is 60 miles (100 kilometers) thick — 10 times deeper than Earth’s oceans — and is buried under a 95-mile (150-kilometer) crust of mostly ice.

That’s more water than contained in all of Earth’s oceans.

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Tiny grains from the interior ocean of Enceladus

5:16 pm

Using Cassini scientists have detected tiny grains of rock orbiting Saturn that they think were formed on the floor of the interior ocean of Enceladus and then spewed out its vents into space.

They believe that these silicon-rich grains originate on the seafloor of Enceladus, where hydrothermal processes are at work. On the seafloor, hot water at a temperature of at least 90 degrees Celsius dissolves minerals from the moon’s rocky interior. The origin of this energy is not well understood, but likely includes a combination of tidal heating as Enceladus orbits Saturn, radioactive decay in the core and chemical reactions.

As the hot water travels upward, it comes into contact with cooler water, causing the minerals to condense out and form nano-grains of ‘silica’ floating in the water. To avoid growing too large, these silica grains must spend a few months to several years at most rising from the seafloor to the surface of the ocean, before being incorporated into larger ice grains in the vents that connect the ocean to the surface of Enceladus. After being ejected into space via the moon’s geysers, the ice grains erode, liberating the tiny rocky inclusions subsequently detected by Cassini.

Additional data suggest that the interior of Enceladus is very porous, which means that interior ocean might not be one large bubble but a complex liquid-filled cave.

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The Milky Way is like ripples in a pond

10:50 am

Milky Way ripples

The uncertainty of science: New survey data of the stars in the Milky Way suggest that the galaxy is not only corrugated with concentric ripples — like you’d see if you dropped a stone in a pond — it is also about 50% larger than previous estimates.

I have watched the size of the Milky Way fluctuate up and down depending on the research for the past forty years. Sometimes it is larger than expected. Sometimes smaller. Without doubt we are getting a better idea of its actual size, but don’t be surprised if the numbers continue to bounce about for decades, even centuries, to come.

The confirmation that the spiral arms are the equivalent of ripples in a pond is also not surprising, as it confirms the intuitive conclusion of anyone who looks at a whirlpool-shaped spiral galaxy: It is a whirlpool spiraling into the gravity well at its center.

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Two astronauts gear up for one year in space

5:14 pm

The final preparations are under way for sending two astronauts, one American and one Russian, to ISS for a full year.

Their launch is scheduled for March 27 in a Soyuz capsule.

One other cool aspect of this long mission: The American astronaut, Scott Kelly, has a twin brother, Mark Kelly, who is also an astronaut, though retired. Mark will be duplicating some of Scott’s in-space activities during the mission. Doctors will also compare how Scott’s body changes in weightlessness over time, in comparison to his brother here on Earth.

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More evidence NOAA has tampered with climate data

9:30 am

More global-warming fraud: Scientists have uncovered more tampering by NOAA of its climate temperature data to create the illusion that the climate is warming.

When Dr. Roy Spencer looked up summer temperature data for the U.S. Corn Belt, it showed no warming trend for over a century. But that was before temperatures were “adjusted” by National Oceanic and Atmospheric Administration climate scientists. Now the same data shows a significant warming trend.

Spencer, a climate scientist at the University of Alabama in Huntsville, said that the National Climatic Data Center made large adjustments to past summer temperatures for the U.S. Corn Belt, lowering past temperatures to make them cooler. Adjusting past temperatures downward creates a significant warming trend in the data that didn’t exist before. “I was updating a U.S. Corn Belt summer temperature and precipitation dataset from the NCDC website, and all of a sudden the no-warming-trend-since-1900 turned into a significant warming trend,” Spencer wrote on his blog, adding that NCDC’s “adjustments” made the warming trend for the region increase from just 0.2 degrees Fahrenheit per century to 0.6 degrees per century.

As Spencer notes, correcting the data for errors would normally cause adjustments in both directions. NOAA’s adjustments, however, are always in one direction: from cooler to warmer. This suggests manipulation and fraud, not an effort to improve the data. And that they have consistently refused to explain their adjustments in detail further reinforces this conclusion.

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Monitoring for a signal from Philae to begin this week

8:48 am

Beginning on Thursday Rosetta engineers will start searching for a signal from their lander Philae, hidden somewhere on the surface of Comet 67P/C-G.

The likelihood of getting an answer this soon is not high, but the lander is now getting about twice as much sunlight as it did when it landed in November. There is a chance it will warm up enough and get enough stored power to come to life.

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Sunspots crash in February

9:54 am


NOAA today posted its monthly update of the solar cycle, showing the sunspot activity for the Sun in February. As I have done monthly for the past five years, I am posting it here below the fold, with annotations to give it context.

In the past two months I have noted how the ramp down from solar maximum has closely tracked the 2009 prediction of the solar scientist community (indicated by the red curve).

In February, however, that close tracking ended, with sunspots plunging far below the prediction. Note also that sunspot activity in March has also been weak.

» Read more

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Americans demand mandatory food labels for DNA

1:48 pm

We are doomed: A new survey has found that more than 80 percent of Americans support the idea of requiring labels on any foods that contain DNA.

If the government does impose mandatory labeling on foods containing DNA, perhaps the label might look something like this: “WARNING: This product contains deoxyribonucleic acid (DNA). The Surgeon General has determined that DNA is linked to a variety of diseases in both animals and humans. In some configurations, it is a risk factor for cancer and heart disease. Pregnant women are at very high risk of passing on DNA to their children.”

I truly fear for the future, not so much because so many people haven’t the slightest idea what DNA is, but because so many people are so eager to force food labeling (or any other regulation you can think of) on others at the slightest whim.

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Drill design flaw source of short circuit on Curiosity

9:47 am

NASA engineers have confirmed that the rover’s drill is the source of the intermittent short circuit that forced them to shut down Curiosity temporarily.

“The most likely cause is an intermittent short in the percussion mechanism of the drill,” Erickson said in a statement. (Curiosity’s drill doesn’t simply rotate; it hammers into rock, via that percussion mechansism, as well.) “After further analysis to confirm that diagnosis, we will be analyzing how to adjust for that in future drilling.” A brief short occurred during a test on Thursday (March 5) that used the drill’s percussive action, NASA officials explained.

This is not a surprise, as it has been known since before launch that a design flaw in the drill could cause short circuits, possibly serious enough to permanently shut down the rover. They have thus used the drill much less than they had originally planned, and with great care.

Once they get a handle on the specifics causing this short, they say that Curiosity will go back into operation. However, I suspect that they may no longer use the drill, or if they do, they will use it under very very very limited circumstances.

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