Tag: science

Closing in on Ceres’s bright spots

9:33 am

Ceres's bright spots

Cool image time! The Dawn science team has released a new close-up of Ceres’s Double Bright Spot.

The new up-close view of Occator crater from Dawn’s current vantage point reveals better-defined shapes of the brightest, central spot and features on the crater floor. Because these spots are so much brighter than the rest of Ceres’ surface, the Dawn team combined two different images into a single composite view — one properly exposed for the bright spots, and one for the surrounding surface.

They have also released a detailed topographic map of the crater as well as a fly-around video, which I have posted below the fold. The interesting take-away from this new data is that, while the bright spots look at first glance remarkably like the snow-cap on a mountain-top, they are actually at the low spots in the crater. This suggests that they are instead material that has either bubbled up from below, or flowed downward to the crater bottom.

Be sure you click on the link and look at the full resolution image.
» Read more

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Venus probe about to rise from the dead

9:07 am

Five years after it failed to enter Venus orbit as planned, the Japanese probe Akatsuki is about to try again, in December.

The article provides an interesting and detailed explanation of what had gone wrong in 2010, and then describes the amazing things engineers have done to make this second attempt even possible. If they succeed it will be one of the most brilliant achievements in the history of space exploration.

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The Earth has a lot of trees!

9:32 am

The uncertainty of science: A new estimate of the number of trees on Earth has increased that estimate seven-fold, from about 400 billion to 3 trillion.

The previously accepted estimate of the world’s tree population, about 400 billion, was based mostly on satellite imagery. Although remote imaging reveals a lot about where forests are, it does not provide the same level of resolution that a person counting trunks would achieve.

Crowther and his colleagues merged these approaches by first gathering data for every continent except Antarctica from various existing ground-based counts covering about 430,000 hectares. These counts allowed them to improve tree-density estimates from satellite imagery. Then the researchers applied those density estimates to areas that lack good ground inventories. For example, survey data from forests in Canada and northern Europe were used to revise estimates from satellite imagery for similar forests in remote parts of Russia.

That these same scientists can, in this same story, also claim with almost certainty that the number of trees on Earth has declined precisely 46% since homo sapiens appeared 12,000 years ago illustrates the difficulty humans have to remain skeptical. How do they get this precise number for the tree count 12,000 years ago? It appears to me that they have allowed the modern environmental agenda of blaming the evil destruction of the environment on humanity to cloud their thinking.

If scientists have discovered a seven-fold error in their count today, I am sure the margin of error for an estimate for 12,000 years ago will be much higher.

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High res radar instrument fails on Earth observation satellite

9:18 am

Only seven months after launch one of the two instruments on NASA’s Soil Moisture Active Passive (SMAP) Earth observation satellite has failed.

Launched on Jan. 31, the Soil Moisture Active Passive spacecraft’s objective is to map global soil moisture and to detect whether soils are frozen or thawed. It is the first mission where scientists have attempted to collect high-resolution, high-accuracy soil moisture data, said Kent Kellogg, SMAP’s JPL-based project manager.

NASA budgeted $916 million for the mission and has been working on it for the past eight years. “We do a lot of testing on the ground to make sure the designs will be built properly and will last in the environment,” Kellogg said. “But space is a very unforgiving place, and we can have these kinds of problems where despite our best efforts with design and vigorous testing, something surprises us. It’s very uncommon, but these things can happen occasionally.”

SMAP’s two scientific tools are an active radar and a passive radiometer. They complement each other, making up for the other’s measurement limitations. The broken radar collected soil moisture and freeze-thaw measurements at a higher resolution of up to 1.9 miles. The still functioning radiometer generates more accurate measurements but its resolution is lower at about 25 miles. [emphasis mine]

I am not satisfied by the explanation for the failure expressed above. NASA spent a lot of money for this science satellite over almost a decade. In addition, we have been launching instruments like this for almost half a century, and have by now learned quite well the engineering necessary to keep them operating under the conditions in low Earth orbit. I suspect a screw-up somewhere, which we might or might not ever identify.

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Apollo lunar samples crumbling to dust

9:08 am

The uncertainty of science: A comparison between the average particle size of 20 Apollo moon soil samples has discovered that their size has decreased by more than half in the past 40 years.

The differences between the two datasets are stark. For example, the median particle diameter has decreased from 78 microns (0.0031 inches) to 33 microns (0.0013 inches). And in the original sieve data, 44 percent of soil particles were between 90 and 1,000 microns (0.0035 to 0.039 inches) wide; today, just 17 percent of the particles are that large.

The most likely explanation for the degradation is damage caused by water vapor, the scientists say. “Leaching by water vapor causes the specific surface area of a lunar soil sample to multiply, and a system of pores develops,” they wrote in the study, which was published online last week in the journal Nature Geoscience. “These structural changes may be attributed to the opening of existing, but previously unavailable, pore structure or the creation of new surfaces through fracturing of cement or dissolution of amorphous particles.”

I was surprised that in the article above the scientists made no mention of gravity as a factor. These particles were originally formed under lunar gravity, 1/6 that of Earth. I would have thought that their structural strength was partly determined by this, and once brought to Earth’s heavier gravity would have thus slowly deteriorated over time.

Either way, the study illustrates why saving these samples for future researchers was a foolish mistake. Time changes all things, and that change has made these samples no longer a good representation of the Moon. The NASA scientists and managers who decided to store these samples instead of distributing them all for immediate study forgot this basic fact.

The scientists who did this study appear to have not learned this lesson as well. They suggest future samples be stored off-Earth, in a place like ISS. I say, we should instead go to the Moon so often we don’t need to store any samples. When we want a sample, we go and get one.

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Technical problems for cosmic ray detector on ISS

9:53 am

The failure of a second of four cooling pumps on the Alpha Magnetic Spectrometer on ISS threatens the science instrument’s ability to continue its observations.

The AMS continues to gather science data using the three remaining pumps. They are part of a liquid carbon dioxide cooling system that is meant to dissipate heat as the AMS, which is on the outside of the space station, cycles in and out of sunlight during each 90-minute orbit of Earth Only one pump is needed at any given time. One failed in February 2014 and at least one of the other three is showing possible signs of trouble.

Since the 8.5-tonne AMS began operating in 2011, it has tracked more than 69 billion cosmic rays flying through its detectors. Its goal is to search for antimatter and dark matter. In 2013, AMS scientists reported measuring numbers and energies of positrons that hinted at, but did not confirm, the existence of dark matter.

The news article suggests that the instrument is now working with only one reliable pump. It also is possible that repairs might be done by astronauts on ISS during a spacewalk.

Some background: AMS cost $2 billion and about 20 years to build. It only got launched because Congress ordered NASA to launch one more shuttle mission to ISS to get it there.

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Curiosity spots a spoon on Mars!

9:04 am

The spoon on Mars

Very cool image time! In one of Curiosity’s recent images of the Martian surface on the slopes of Mount Sharp appears what looks like a long thin spoon jutting horizontally out of the ground.

The shadow below the feature is strong evidence that that this almost certainly a real object, shaped exactly as we see it. However, it is not an artificially created spoon. If you look at both the full raw image as well as zoom in on the feature itself, you will see that it is something that formed naturally due to Mars’ low gravity and the geology here. The spoon is a thin prong of harder material that has remained intact as the ground below it has been slowly eroded away by the ever-present but very weak Martian wind. If you look close you can see that harder material extend back into the rock behind the spoon.

Some of that erosion might also have been caused by flowing water sometime in the past, but to confirm this will take additional geological research.

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Data from New Horizons does not match what is seen from Earth

9:10 am

The uncertainty of science: Planetary geologists are presently baffled by a conflict in the atmospheric data between New Horizons and data gathered from Earth.

On 29 June, a few weeks before the fly-by, Young organized astronomers across New Zealand and Australia to watch Pluto as it passed in front of a distant star. Tracking how the star’s light faded during the passage provided information on how much gas is in Pluto’s atmosphere. Using the same method, planetary scientists have seen the atmosphere grow denser since 1988 — and analysis of the 29 June observations shows that the trend remains intact. Young calculates that the current atmospheric pressure at Pluto’s surface is 22 microbars (0.022 pascals), or 22-millionths the pressure at sea level on Earth.

But on 14 July, New Horizons measured Pluto’s surface pressure as much lower than that ­— just 5 microbars. “How we link the two, we’re still working on,” says Cathy Olkin, a deputy project scientist for New Horizons at SwRI.

The difference could simply be that Pluto’s atmosphere is not smooth, that some regions are dense while others are thin, and New Horizons happened to look at a thin place. The Earth observations don’t have the resolution to separate the two.

There are other proposals to explain the problem. Regardless, the answer is likely hidden in the data from New Horizons that has still not been downloaded back to Earth. In a few months, all might very well become clear.

Or not, as is the natural state of science.

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On the radio

5:07 pm

I will be doing another two hours with Georgy Noory on Coast to Coast on Tuesday night from midnight to 2 am, providing him an update of some of the real space and science news that has occurred in the past month, since my last appearance. Tune in for some fun stuff!

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New Horizons team picks its next Kuiper Belt target

3:07 pm

The New Horizons science team has picked its next Kuiper Belt fly-by target beyond Pluto.

New Horizons will perform a series of four maneuvers in late October and early November to set its course toward 2014 MU69 – nicknamed “PT1” (for “Potential Target 1”) – which it expects to reach on January 1, 2019. Any delays from those dates would cost precious fuel and add mission risk. “2014 MU69 is a great choice because it is just the kind of ancient KBO, formed where it orbits now, that the Decadal Survey desired us to fly by,” said New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI) in Boulder, Colorado. “Moreover, this KBO costs less fuel to reach [than other candidate targets], leaving more fuel for the flyby, for ancillary science, and greater fuel reserves to protect against the unforeseen.”

The press release includes some silly gobbly-gook about how the science team can’t announce this as its official target because they still have to write up a proposal to submit to NASA, which then must ponder their decision and decree it valid. We all know this is ridiculous. Will NASA sit and ponder and make them miss their target? I doubt it.

The fly-by itself will be really exciting, because this object will truly be the most unusual we will have ever gotten a close look at, as it has spent its entire existence far out in the dim reaches of the solar system.

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Comet 67P/C-G goes boom!

7:48 am

Outburst on Comet 67P/C-G

Cool image time! On August 22, just days after its closest approach to the sun, Rosetta caught the outburst, image above, from the larger lobe on Comet 67P/C-G.

The image scale is 28.6 m/pixel and the image measures 29.3 km across. Although the activity is extraordinarily bright even in the original (below), the image above has been lightly enhanced to give a better view of the outline of the nucleus in the lower part of the image, as well as to show the full extent of the activity.

The most interesting images, I think, will actually come later, when the activity dies down and they can bring Rosetta in closer again. We will then be able to compare the nucleus both before and after this outburst, getting a sense of how the comet changes with each close pass to the sun.

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More than half of published psychology papers cannot be replicated

11:51 am

The uncertainty of science: An attempt to replicate 98 different psychological research studies has found that significantly less than half could be replicated.

In the biggest project of its kind, Brian Nosek, a social psychologist and head of the Center for Open Science in Charlottesville, Virginia, and 269 co-authors repeated work reported in 98 original papers from three psychology journals, to see if they independently came up with the same results. The studies they took on ranged from whether expressing insecurities perpetuates them to differences in how children and adults respond to fear stimuli, to effective ways to teach arithmetic.

According to the replicators’ qualitative assessments, as previously reported by Nature, only 39 of the 100 replication attempts were successful. … There is no way of knowing whether any individual paper is true or false from this work, says Nosek. Either the original or the replication work could be flawed, or crucial differences between the two might be unappreciated. Overall, however, the project points to widespread publication of work that does not stand up to scrutiny. [emphasis mine]

None of this surprises me. The focus of much science research, especially in the soft sciences like psychology, is statistical in nature and easily manipulated. In fact, most of it isn’t science at all, but an attempt to use mere statistics to prove a point. Science would instead try to find out why something happens, not just demonstrate through statistics that it does.

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IAU balks at some Pluto names picked by New Horizons team

9:12 am

Irritated that the New Horizons team did not consult with the International Astronomical Union (IAU) before it announced its proposed names for many Pluto features, IAU officials are now threatening to reject them once submitted.

“Frankly, we would have preferred that the New Horizons team had approached us before putting all these informal names everywhere,” said Rosaly Lopes, a senior research scientist at NASA’s Jet Propulsion Laboratory who is a member of the IAU’s Working Group for Planetary System Nomenclature.

The group’s chair, Rita Schulz of the European Space Agency, said the New Horizons team has not yet submitted a formal proposal for naming features on Pluto and its moons. “Usually, there are always some features for which this process goes rather fast, some for which more checks and balances are required (which then takes a bit longer) and there are usually also some names or descriptors that cannot be approved and need to be replaced by others,” she told GeekWire in an email.

There has been a conflict between the IAU and the principal investigator for New Horizons, Alan Stern, for years now. Stern also runs the private company Uwingu, which offers citizens the ability to name unnamed craters on Mars for a fee, without asking the IAU. Stern, like myself, believes that the IAU’s claim that it is the only authority that can approve names for every object not on Earth is hogwash. Stern also strongly objects to the IAU’s decision to demote Pluto’s planetary status to a dwarf planet.

These comments by IAU officials suggest that they are being somewhat petty and are threatening to reject the New Horizons names to get back at Stern.

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New Hubble image of Twin Jet Nebula

8:27 am

Twin Jet Nebula

Astronomers using the Hubble Space Telescope have taken a new image of the Twin Jet Nebula, a planetary nebula officially called PM M2-9.

The M in this name refers to Rudolph Minkowski, a German-American astronomer who discovered the nebula in 1947. The PN, meanwhile, refers to the fact that M2-9 is a planetary nebula. The glowing and expanding shells of gas clearly visible in this image represent the final stages of life for an old star of low to intermediate mass. The star has not only ejected its outer layers, but the exposed remnant core is now illuminating these layers — resulting in a spectacular light show like the one seen here. However, the Twin Jet Nebula is not just any planetary nebula, it is a bipolar nebula.

The bipolar nature of the nebula is thought to be caused by the interaction of a binary star system. I like to say that the orbiting stars act like the blades in a blender, mixing the ejected layers of material to produce the jets and shapes that make planetary nebula so beautiful.

Hubble first imaged this nebula in 1997. This image, using the telescope’s newer instruments, is important because it shows the complex layers within each jet, suggesting multiple ejection events in the past.

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An update on Gaia’s first year of astronomical observations

11:43 pm

European scientists today released an update on the status and scientific observations of their space telescope Gaia, designed to survey the location and distance of a billion stars.

The press release provides a basic summary of the spacecraft’s condition, which appears good, as well as an overview of some of the most interesting observations, though with little detail. This is because the first scheduled release of Gaia hard data will not happen until a year from now, thus giving the scientists who run the project a year to analyze it and publish their own papers.

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Cubesats to the Moon!

5:05 pm

NASA has chosen three cubesat missions to fly lunar planetary orbiters to the Moon, to be launched on the first SLS flight in 2018.

LunaH-Map, along with a number of other deep-space CubeSats, is a candidate to fly to lunar orbit on Exploration Mission-1, the first flight of NASA’s Space Launch System (SLS), which will be the most powerful rocket ever built and will enable astronauts in the Orion spacecraft to travel deeper into the solar system. NASA will provide several CubeSat missions spots on the maiden SLS mission. LunaH-Map is a 6U (“6 unit”) CubeSat. One “unit” is a cube measuring 4.7 inches on a side; LunaH-Map strings six of these CubeSat building blocks together and weighs as much as a small child (about 30 pounds). …

“NASA has funded three different CubeSats to learn more: Lunar IceCube, Lunar FLASHLIGHT and LunaH-Map. They all look for water in different ways and provide different types of information,” [said principal investigator Craig Hardgrove].

The article is focused on LunaH-Map, not on the other two cubesats, but the fact that NASA plans to use “the most powerful rocket ever built” to launch the first three planetary cubesats, so small they could almost be launched by a model rocket, illustrates some of the problems of the SLS program. Even though that first SLS flight is likely to happen, I suspect that, should it falter for any reason (something that would not surprise me), these cubesats could easily be launched on another rocket, and will be.

Putting SLS aside, however, the building of these first planetary cubesats is a very significant development. It once again signals the way unmanned satellite engineering is evolving, finding ways to build spacecraft smaller and less costly.

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