Tag: science

Oxygen in Comet 67P/C-G coma

8:38 am

The uncertainty of science: Unexpectedly scientists using Rosetta data have discovered oxygen in the coma of Comet 67P/C-G.

It was not immediately clear where the oxygen came from. The team discovered that water and oxygen were often found together — an indication that similar processes released both molecules. But Bieler and his colleagues ruled out many scenarios in which oxygen arises as a by-product when energetic particles such as photons and electrons split apart water. Instead, the researchers argue that the oxygen is a remnant from when 67P formed billions of years ago, a process that may have trapped the gas in small grains of ice and rock that coalesced to create the comet’s solid core.

But many models of the early Solar System rule this out because most oxygen tends to pair off with hydrogen. Given this affinity, it is tricky to adjust models of the early Solar System to allow for the survival of gaseous O2, says Mike A’Hearn, an astronomer at the University of Maryland in College Park and a co-investigator on Alice. But he adds that it may be possible with the right chemical abundances and temperature conditions.

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A mother and father is still the best for kids

2:14 pm

Science discovers the obvious: Several new studies have found again that children generally do better in a stable family with a mother and a father than in any other combination.

In recent weeks, a barrage of new evidence has come to light demonstrating what was once common sense. “Family structure matters” (in the words of my American Enterprise Institute colleague Brad Wilcox, who is also the director of the National Marriage Project at the University of Virginia). Princeton University and the left-of-center Brookings Institution released a study that reported “most scholars now agree that children raised by two biological parents in a stable marriage do better than children in other family forms across a wide range of outcomes.” Why this is so is still hotly contested.

Another study, co-authored by Wilcox, found that states with more married parents do better on a broad range of economic indicators, including upward mobility for poor children and lower rates of child poverty. On most economic indicators, the Washington Post summarized, “the share of parents who are married in a state is a better predictor of that state’s economic health than the racial composition and educational attainment of the state’s residents.”

I think it amusing that some scientists wonder “why this is so.” I also realize that by stating this obvious fact of nature I and these scientists are being racist homophobes who want to oppress minorities, but who am I to argue with reality?

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Comet 67P/C-G has passed peak brightness

9:31 am

Using both ground-based and Rosetta observations scientists have now measured when the comet reached its peak brightness as well as how much material it lost during this orbit’s closest approach to the Sun.

Based on Rosetta’s pre-perihelion measurements that indicate the dust:gas ratio was approximately 4 , that means roughly 80% of the material being lost is dust, with the rest dominated by water, CO, and CO2 ices. (Note: at the time of that blog post an estimate of 3 was made for perihelion, but the actual data has yet to be analysed.) In any case, using 3 and 4 respectively, the total mass loss rate at its peak is likely in the range of about 100,000–115,000 tonnes per day.

Of course, that’s not a huge amount compared to the comet’s overall mass of around 10 billion tonnes. But nevertheless, a very simple calculation reveals that if, for example, the comet lost that much mass continuously for 100 days, it would correspond to roughly 0.4-0.5 metres of its surface being removed in that time.

In other words, the surface lost about 1.5 feet during close approach.

Peak brightness occurred near the end of August, and has been declining since.

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Dawn begins descent to final orbit around Ceres

8:33 pm

Engineers have fired up Dawn’s ion engine and have begun lowering the spacecraft’s orbit downward.

The spacecraft is now on its way to the final orbit of the mission, called the low-altitude mapping orbit. Dawn will spend more than seven weeks descending to this vantage point, which will be less than 235 miles (380 kilometers) from the surface of Ceres. In mid-December, Dawn will begin taking observations from this orbit, including images at a resolution of 120 feet (35 meters) per pixel.

They’ve also released a nice mosaic showing the double bright spots in Occator Crater as well as the surrounding terrain.

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Pluto’s meandering canyons

8:52 am

canyons of Pluto

Cool image time! In scrolling through the new raw images downloaded from New Horizons today I came across an image, one of several, that showed what clearly appeared to be meandering canyons carved by flowing liquid.

To show it here, I have cropped it and reduced its size somewhat, highlighting the most interesting features. As you can see, the largest canyon not only appears to have a dark floor, it cuts right through an older crater. Smaller canyons do the same thing. In addition, many of the craters seem to be ponded with the same dark material that floors the canyons, while some of the smaller canyons show tributaries that come together, just like rivers. Are these flows of liquid nitrogen?

I eagerly await the conclusions of the scientists, who are probably only slightly less baffled by these features as I am.

Be sure and check out the full image, as well as the other raw images. The data continue to come in from New Horizons, but the science team is no longer under the same kind of public pressure to make announcements or hold press conferences. There are gems hidden there that are worth looking at, even if they are not as yet accompanied by any scientific analysis.

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Pluto in 3D

9:09 am

The New Horizons science team has released its first 3D image of the surface of Pluto.

You need red/blue stereo glasses to view it.

The image shows an ancient, heavily cratered region of Pluto, dotted with low hills and cut by deep fractures, which indicate extension of Pluto’s crust. Analysis of these stereo images shows that the steep fracture in the upper left of the image is about 1 mile (1.6 kilometers) deep, and the craters in the lower right part of the image are up to 1.3 miles (2.1 km) deep. Smallest visible details are about 0.4 miles (0.6 kilometers) across.

My impression of the image, using the glasses, makes me wonder if they have exaggerated the vertical depth so that it would stand out. The craters look more like pits than craters. And if they didn’t exaggerate the vertical depth, then that means that impacts on Pluto produce craters that are very different than those seen in the inner solar system.

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Mysterious piece of space junk to hit Earth

8:34 am

A piece of unidentified space junk, discovered in a long elliptical orbit going out far beyond the Moon, has been calculated to hit the Earth over the Indian Ocean on November 13.

WT1190F was detected by the Catalina Sky Survey, a program aimed at discovering asteroids and comets that swing close to Earth. At first scientists didn’t know what to make of this weird body. But they quickly computed its trajectory, after collecting more observations and unearthing 2012 and 2013 sightings from telescope archives, says independent astronomy software developer Bill Gray, who has been working to track the debris with NASA’s Jet Propulsion Laboratory in Pasadena, California.

WT1190F travels a highly elliptical orbit, swinging out twice as far as the Earth-Moon distance, Gray says. Gray’s calculations show that it will hit the Earth at 6:20 UTC, falling about 65 kilometres off the southern tip of Sri Lanka. Much if not all of it will burn up in the atmosphere, but “I would not necessarily want to be going fishing directly underneath it,” Gray says.

What makes the object interesting is that they don’t know when it was launched or how it got in the orbit it is in. It could even be something from the Apollo lunar missions.

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The largest astronomical image ever

8:44 am

Astronomers have assembled the largest single image of the entire Milky Way ever taken.

It is 46 billion pixels across.

The amazing view of the Milky Way was built out of 268 individual views of the galaxy that includes the sun and the Earth, captured night after night over the course of five years with telescopes in Chile’s Atacama Desert. Astronomers at Ruhr-Universität Bochum used the data to examine stars whose brightness changes over time — and the image portrays more than 50,000 new objects with variable brightness that have never been recorded before.

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Another Pluto Moon revealed

8:16 am

Kerberos

The uncertainty of science: The New Horizons science team has released their best image of Pluto’s moon Kerberos, finding it to be nothing like what they expected.

Before the New Horizons encounter with Pluto, researchers had used Hubble Space Telescope images to “weigh” Kerberos by measuring its gravitational influence on its neighboring moons. That influence was surprisingly strong, considering how faint Kerberos was. They theorized that Kerberos was relatively large and massive, appearing faint only because its surface was covered in dark material. But the small, bright-surfaced, Kerberos now revealed by these new images show that that idea was incorrect, for reasons that are not yet understood.

Instead, Kerberos is much smaller than expected, and its surface is bright, suggesting it is covered by relatively clean ice. It is also double lobed, kind of like Comet 67P/C-G.

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Earth might be one of the universe’s first habitable planets

9:57 pm

The uncertainty of science: An analysis of data from the Hubble Space Telescope and Kepler suggests that the Earth might be one of the first planets in the universe to harbor life.

I label this result uncertain because it is based on what I consider to be a very poor sampling of exoplanets as seen by Kepler. Kepler might have found a lot of exoplanets, but the numbers are still small and skewed by the limited types of suns observed and the short time frame of its observations. Moreover, the data from Hubble is rich, but also quite small, leaving great uncertainties for all of these conclusions.

At the same time, this conclusion might help explain why, after almost a half century of looking, we have yet to detect any evidence of radio communications from any other civilizations. You would think we would have detected something by now. Maybe they don’t exist, and we are the first.

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200 new lunar impact craters discovered

9:18 am

In a paper [pdf] presented this week at a lunar science conference, scientists announced the identification of more than 200 new impact craters on the Moon from Lunar Reconnaissance Orbiter (LRO).

As of 1 May 2015, we have scanned and classified changes in 14,182 NAC temporal pairs using our automated change detection tool leading to the discovery over 200 impact craters ranging in size from 1.5 to 43 m. In addition, we also identified thousands of other surface changes, including about 44,000 low reflectance splotches, 3,500 high reflectance splotches, 850 mixed reflectance splotches, [and] 1 Chinese lander/rover.

They think the splotches are created from impacts too small to see with LRO.

Hat tip James Fincannon.

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New cheap way to turn sea water drinkable?

8:25 am

Egyptian researchers have developed what they think could be a cheap and easy way to desalinate sea water.

In a paper published last month in the journal, Water Science & Technology, researchers Mona Naim, Mahmoud Elewa, Ahmed El-Shafei and Abeer Moneer announced that they have developed a new way to purify sea water using materials that can be manufactured easily and cheaply in most countries, and a method that does not rely on electricity.

The technology uses a method of separating liquids and solids called pervaporation. Pervaporation is a simple, two-step process – the first step involves filtering the liquid through a ceramic or polymeric membrane, while the second step requires vaporizing and collecting the condensed water. Pervaporation is faster, cleaner and more energy efficient than conventional methods, not least because the heat required for the vaporization stage does not necessarily have to be electrically generated.

The technology is not yet proven, but if it bears fruit, many of the world’s water problems will soon vanish.

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Study questions scientific dating method

8:32 am

The uncertainty of science: A new study has raised questions about the methods scientists have used to date the late heavy bombardment in the early solar system.

A study of zircons from a gigantic meteorite impact in South Africa, now online in the journal Geology, casts doubt on the methods used to date lunar impacts. The critical problem, says lead author Aaron Cavosie, a visiting professor of geoscience and member of the NASA Astrobiology Institute at the University of Wisconsin-Madison, is the fact that lunar zircons are “ex situ,” meaning removed from the rock in which they formed, which deprives geoscientists of corroborating evidence of impact. “While zircon is one of the best isotopic clocks for dating many geological processes,” Cavosie says, “our results show that it is very challenging to use ex situ zircon to date a large impact of known age.”

The problem is that the removal of the zircon from lunar rocks changes the data enough to make the dating unreliable. The method might work on Earth, but the dating done on Apollo samples can be questioned. This means that much of the supposed history of the solar system, centered on what planetary scientists call the late heavy bombardment, a period 4 billion years ago when the planets were being hit by innumerable impacts as they cleared the solar system of its dusty debris disk, might not have happened as dated from lunar samples. If so, our understanding of when that bombardment ended and life began to form on Earth might be considerably incorrect.

The solution? Get to the planets in person, where you can obtain many samples in situ and thus gather a much deeper understanding of the geology.

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Fractures on Enceladus’s north pole

6:02 pm

Enceladus's North Pole

The Cassini science team has released the first image from Wednesday’s flyby of the Saturn moon Enceladus.

Scientists expected the north polar region of Enceladus to be heavily cratered, based on low-resolution images from the Voyager mission, but the new high-resolution Cassini images show a landscape of stark contrasts. “The northern regions are crisscrossed by a spidery network of gossamer-thin cracks that slice through the craters,” said Paul Helfenstein, a member of the Cassini imaging team at Cornell University, Ithaca, New York. “These thin cracks are ubiquitous on Enceladus, and now we see that they extend across the northern terrains as well.”

To see more you can browse the raw images here.

The next flyby later this month will be especially interesting as they will dip to within 30 miles of the surface.

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More evidence of giant flash floods on Mars

9:45 am

Mangala Valles

A newly released image from ESA’s Mars Express orbiter shows that catastrophic flooding — caused by ice melted from volcanic activity — created the Mangala Valles channels on Mars.

The perspective image on the right shows the topography of the region, with low points indicated in blue and high points by red. The channel along the right side of the image is Mangala Valles itself, though you can also see additional flood channels to the left of it passing around and through a large crater whose floor now stands above the surrounding terrain caused by the erosion of the rim plus the deposit of sediment inside the crater during the flooding.

I have a soft spot for Mangala Valles. When it was first photographed by the first orbiter missions to Mars in the early 1970s I was struck by its river-like appearance and striking topography. I therefore placed my Martian colony here in one of my efforts at science fiction writing. I figured it a good location for colonization, as there would likely be water and, by roofing over the deep canyon, a colony could be built relatively easily.

Better locations on Mars have since been found, but the location still intrigues me.

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Real clam digging

6:01 pm

An evening pause: Rocco had suggested this short video about the joys of going out and digging clams. I prefer the video below, of a real clam doing its own digging, because it shows us something we normally don’t see and that is really amazing. Who would have thought that a clam could bury itself so quickly, with a single digging foot?

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Kepler finds a star no one can explain

3:56 pm

Observations using Kepler have uncovered a star whose light fluctuations can only be explained in two ways.

First,

If another star had passed through the unusual star’s system, it could have yanked a sea of comets inward. Provided there were enough of them, the comets could have made the dimming pattern. But that would be an extraordinary coincidence, if that happened so recently, only a few millennia before humans developed the tech to loft a telescope into space. That’s a narrow band of time, cosmically speaking.

Second? Maybe the star’s light is being blocked by a swarm of megastructures built by an alien civilization. They intend to look for radio emissions from the star in wavelengths associated with technology to see if this theory has any possibility.

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New global maps of Titan

11:23 am

Titan's North Pole

The Cassini science team has released new maps of Titan, including new maps of both poles, assembled from images taken during the 100 flybys that the spacecraft has made of the moon since it arrived in orbit around Saturn.

The scale is rough, just less than a mile at best, and there is no topographic information because the thick atmosphere allows for no strong sunlight or shadows. The images show differences in surface brightness, which does tell us where Titan’s dark methane lakes are.

This is likely the best we will get of Titan for decades, until another spacecraft is sent there.

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Cassini’s last flybys of Enceladus

2:04 pm

As Cassini approaches the end of its decade-long mission at Saturn it will begin its last series of flybys of the moon Enceladus starting October 14.

Images will arrive a day or two afterward. The last two flybys will take place in late October and then in December, with the second October flyby getting closest, only 30 miles from the surface.

Beginning next year they will shift the spacecraft’s orbit so that it can get a better look at Saturn’s poles during its last two years. In that orbit flybys of the moons cannot be done.

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New weather maps of Jupiter

1:27 pm

Using the Hubble Space Telescope astronomers have compiled a new set of maps of Jupiter, showing changes in the gas giant’s bands and spots, including the Giant Red Spot.

The scientists behind the new images took pictures of Jupiter using Hubble’s Wide Field Camera 3 over a ten-hour period and have produced two maps of the entire planet from the observations. These maps make it possible to determine the speeds of Jupiter’s winds, to identify different phenomena in its atmosphere and to track changes in its most famous features.

The new images confirm that the huge storm, which has raged on Jupiter’s surface for at least three hundred years, continues to shrink, but that it may not go out without a fight. The storm, known as the Great Red Spot, is seen here swirling at the centre of the image of the planet. It has been decreasing in size at a noticeably faster rate from year to year for some time. But now, the rate of shrinkage seems to be slowing again, even though the spot is still about 240 kilometres smaller than it was in 2014.

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Solar ramp down jumps slightly

9:56 am

My original post about NOAA’s October update to its monthly tracking of the Sun’s sunspot cycle contained an incorrect graph. For reasons I do not understand, the first graph they posted did not include the data for September, thus creating for me the illusion that little had changed in September. I am now posting the correct graph here, below the fold, with annotations to give it context.

In September numbers showed a slight jump in sunspot activity, though once again nothing so significant as to change the overall trends. Moreover, the correction doesn’t change what I wrote previously in any way: the rate of decline seems to have transitioned down from the 2009 prediction (red curve) to the 2007 weak prediction (lower green curve). This doesn’t real mean much, as the sunspot number can still vary up and down considerable before we reach solar minimum in two or three years.

» Read more

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Getting India’s first space telescope working

9:12 am

A moment of terror: During the first week of successful operation, there was an initial moment of terror when the engineers checking out Astrosat, India’s first space telescope, thought the spacecraft was unable to point at its target accurately.

During the first orbit, there was a difficulty in detecting this Crab Nebula as the satellite happened to pass through the South Atlantic Anomaly (SAA) region when Crab was in the field of view. SAA avoidance zone was deliberately kept wide to protect the instruments, and detectors were switched OFF in this interval during the initial days of Astrosat operation. When all the data were systematically analysed and data were selected based on the availability of Crab in the detector field of view, one could see the Crab emerging from Earth’s shadow (Fig 3).

Using the Crab Nebula as Astrosat’s first target, the check-out has been proceeding well, with full research operations expected to begin in the next few weeks.

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Back from a weekend underground

9:22 pm

Bob Zimmerman underground

The picture on the right will explain why I have been silent posting since Friday. I have just returned with five friends from three days of caving in New Mexico, doing some wild caving plus my first visit to Carlsbad Caverns since 1992, guided by a local caver who has been helping me with my cave survey project in Arizona.

New Mexico probably has the largest concentration of truly large and spectacularly decorated caves in the entire world. I’ve caved there previously, but this was my first trip driving from Arizona. We went to two wild caves, one of which I had never visited before and a second that I had seen during my 1992 trip. The picture shows me in the latter, standing above a large clear pool near the back of the cave with some giant flowstone speleothems all around me.

The new cave contained a room dubbed Speleogasm, because every formation there, of which there are too many to count, is completely festooned with helectites and sodastraws in a mad protrusion that no geologist can as yet explain. Nor is there any way to describe it adequately or photograph it successfully. To witness it you need to go, requiring the specialized caving skills that include the techniques and equipment required to rappel and climb a 40 foot rope.

As always, the advantages of learning how to do this successfully is the reward of seeing things that few ever see. It is why engineers and scientists strive so hard to get planetary probes to distant planets. And why humans want to travel to the planets. For me, getting inside a remote and beautifully decorated cave will just have to do.

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3D image of Comet 67P/C-G

9:06 am

Do you own red-blue 3-D glasses? Get them out and go to this link. Rosetta scientists have created a 3-D image of Comet 67P/C-G, including the jets of material shooting out from its surface.

[C]reating a 3d anaglyph of dynamic events like this is notoriously difficult: often the jets are too faint or their duration is too short to find two high-quality images taken several minutes apart that are suitable to pair together to create this type of view. However, the OSIRIS team got lucky with this particular event, capturing two images separated by about two-and-a-half minutes.

The image shows a bright, collimated jet embedded in a broader emission structure. The three dimensional perspective also reveals the conical shape of the jet and that the collimated feature is emitted towards the observer.

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Sunlight rolled the rocks on an asteroid

8:53 am

Scientists studying the rounded rocks on the surface of the asteroid 25143 Itokawa, photographed by the Japanese probe Hayabusa, have concluded that sunlight combined with the asteroid’s tiny gravity caused them move and thus erode themselves.

As sunlight bounced off the orbiting boulders, photons provided a tiny push. As they radiated back outward as heat, they triggered a recoil effect that added a gentle spin. Over time, these slowly spinning boulders bumped into each other with enough force to wear their edges into smooth surfaces.

Warning! This is only a model, and thus could very well be wrong. It is reasonable however and worth considering as a factor in studying the early formation history of asteroids.

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