Tag: science

Baby stars at center of galaxy

2:40 pm

New observations of the region surrounding Sagittarius A* (Sgr A*), the super-massive black hole at the center of the Milky Way, has confirmed earlier research by finding what appears to be eleven newly formed baby stars.

Prior observations of the region surrounding Sgr A* by Zadeh and his team had revealed multiple massive infant stars but the finding was not conclusive. These objects, known as proplyds, are common features in more placid star-forming regions, like the Orion Nebula. The new measurements provide more conclusive evidence for young star formation activity. Though the galactic center is a challenging environment for star formation, it is possible for particularly dense cores of hydrogen gas to cross the necessary threshold and forge new stars.

The new ALMA observations, however, revealed something even more remarkable, signs that 11 low-mass protostars are forming within one parsec – a scant three light-years – of the galaxy’s central black hole. Zadeh and his team used ALMA to confirm that the masses and momentum transfer rates – the ability of the protostar jets to plow through surrounding interstellar material – are consistent with young protostars found throughout the disk of our galaxy. “This discovery provides evidence that star formation is taking place within clouds surprisingly close to Sagittarius A*,” said Al Wootten with the National Radio Astronomy Observatory in Charlottesville, Virginia, and co-author on the paper.

They have several theories on how new stars could coalesce in such a violent and turbulent region, but none appears that convincing. Essentially, this is a mystery that does not yet have an answer. It does tell us however that star formation can occur almost anywhere.

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The organic dust of Comet 67P/C-G

11:36 am

A study of the dust released by Comet 67P/C-G and captured by Rosetta shows that carbon molecules appear to comprise the comet’s largest component, and that this material is found in the form of very large macromolecules.

As the study shows, organic molecules are among those ingredients at the top of the list. These account for about 45 percent of the weight of the solid cometary material. “Rosetta’s comet thus belongs to the most carbon-rich bodies we know in the solar system,” says MPS scientist and COSIMA team member Dr. Oliver Stenzel. The other part of the total weight, about 55 percent, is provided by mineral substances, mainly silicates. It is striking that they are almost exclusively non-hydrated minerals i.e. missing water compounds. “Of course, Rosetta’s comet contains water like any other comet, too,” says Hilchenbach. “But because comets have spent most of their time at the icy rim of the solar system, it has almost always been frozen and could not react with the minerals.” The researchers therefore regard the lack of hydrated minerals in the comet’s dust as an indication that 67P contains very pristine material.

…The current findings also touch on our ideas of how life on Earth came about. In a previous publication, the COSIMA team was able to show that the carbon found in Rosetta’s comet is mainly in the form of large, organic macromolecules. Together with the current study, it becomes clear that these compounds make up a large part of the cometary material. Thus, if comets indeed supplied the early Earth with organic matter, as many researchers assume, it would probably have been mainly in the form of such macromolecules.

Organic here does not mean life, but is instead used as chemists use it, to mean the molecule includes the element carbon. The results do suggest however that the early solar system had a lot of carbon available, and that much of it was in a relatively pure form available to interact with other elements.

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Chinese space probe detects possible dark matter signal

8:56 am

The uncertainty of science: A Chinese space probe designed to measure cosmic rays has detected a pattern that could be evidence of the existence of dark matter.

Researchers launched the spacecraft from the Jiuquan Satellite Launch Center in the Gobi Desert, about 1600 kilometers west of Beijing, in December 2015. Its primary instrument—a stack of thin, crisscrossed detector strips—is tuned to observe the incoming direction, energy, and electric charge of the particles that make up cosmic rays, particularly electrons and positrons, the antimatter counterparts of electrons. Cosmic rays emanate from conventional astrophysical objects, like exploding supernovae in the galaxy. But if dark matter consists of WIMPs, these would occasionally annihilate each other and create electron-positron pairs, which might be detected as an excess over the expected abundance of particles from conventional objects.

In its first 530 days of scientific observations, DAMPE detected 1.5 million cosmic ray electrons and positrons above a certain energy threshold. When researchers plot of the number of particles against their energy, they’d expect to see a smooth curve. But previous experiments have hinted at an anomalous break in the curve. Now, DAMPE has confirmed that deviation. “It may be evidence of dark matter,” but the break in the curve “may be from some other cosmic ray source,” says astrophysicist Chang Jin, who leads the collaboration at the Chinese Academy of Science’s (CAS’s) Purple Mountain Observatory (PMO) in Nanjing. [emphasis mine]

I must emphasize the large uncertainty here. They have not detected dark matter. Not even close. What they have detected is a pattern in how the spacecraft is detecting cosmic rays that was predicted by the existence of dark matter. That pattern however could have other causes, and the consistent failure of other efforts to directly find dark matter strengthens the possibility that this break is caused by those other causes.

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“Yeti” DNA found to come from bears and dogs

8:59 am

Scientists analyzing DNA samples said to come from either the legendary yeti in the Himalayas or sasquatch in North America have found that all come from known ordinary animals, mostly bears.

Of the nine “yeti” samples, eight turned out to be from bears native to the area, the researchers report today in the Proceedings of the Royal Society B. The other sample came from a dog. Similar studies of hair samples supposedly related to North America’s big hairy hominid, the sasquatch (aka Bigfoot), have revealed that those fibers came from bears, horses, dogs, and a variety of other creatures—even a human.

Debunking aside, the new study also yielded lots of scientifically useful info, Lindqvist says. The analyses generated the first full mitochondrial genomes for the Himalayan brown bear (Ursus arctos isabellinus) and the Himalayan black bear (Ursus thibetanus laniger), for example. That could help scientists figure out how genetically different these rare subspecies are from more common species, as well as the last time these groups shared maternal ancestors in the past.

While we must always recognize the uncertainties of science, we must also recognize when it provides us clarity. This is an example of the latter.

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Wind eating away the Martian terrain

9:44 am

Yardangs on Mars

Cool image time! The Mars Reconnaissance Orbiter (MRO) image on the right, cropped and reduced in resolution to post here, shows the transition zone between the lower flat plain to the north and the higher but rougher region to the south. What makes it interesting is the north-south aligned mesas. These are yardangs, a geological feature that actually acts like a weather vane.

Yardangs are composed of sand grains that have clumped together and have become more resistant to erosion than their surrounding materials.

As the winds of Mars blow and erode away at the landscape, the more cohesive rock is left behind as a standing feature. (This Context Camera image shows several examples of yardangs that overlie the darker iron-rich material that makes up the lava plains in the southern portion of Elysium Planitia.) Resistant as they may be, the yardangs are not permanent, and will eventually be eroded away by the persistence of the Martian winds.

For scientists observing the Red Planet, yardangs serve as a useful indicator of regional prevailing wind direction. The sandy structures are slowly eroded down and carved into elongated shapes that point in the downwind direction, like giant weathervanes. In this instance, the yardangs are all aligned, pointing towards north-northwest. This shows that the winds in this area generally gust in that direction.

Crater splash

The wind comes from the southeast and blows to the northwest, and is slowly wearing down the southern rougher terrain. Why some of these yardangs are surrounded by dark material remains a mystery, as noted I noted in a previous post.

Meanwhile, the northern plain is not as boring as it seems. Only a short distance to the north is an unusual crater, cropped from the full image to show here on the right. To my eye, when this impact occurred it literally caused a splashlike feature of compressed and more resistant material. Over time, the prevailing wind has eroded away the surrounding less resistant regolith to better reveal that splash, leaving behind a mesa with a crater in its center.

Why the impact created this splash tells us something about the density and make-up of the plain. It suggests to me a surface that was once muddy and soft that over time has hardened like sandstone.

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Worms on Mars!

9:09 am

Scientists growing plants on Earth using a simulated Martian soil have found that earthworms like it.

These slimy invertebrates play a key role in making Earth soil healthy by digesting dead organic matter and excreting a potent fertilizer that helps release nutrients like nitrogen and phosphorus. Their constant burrowing also helps lighten up the soil, allowing air and water to seep through better.

That’s an important improvement for the simulated Mars soil, which water struggled to soak through in previous tests. Altogether, the tests showed that the combination of worms and pig slurry helped the plants grow in Martin soil, and the worms not only thrived but reproduced. “Clearly the manure stimulated growth, especially in the Mars soil simulant, and we saw that the worms were active,” says Wamelink. “However, the best surprise came at the end of the experiment when we found two young worms in the Mars soil simulant.”

Obviously, we do not know yet how the worms would respond to the lower Martian gravity, but it sure would be a significant experiment to see them reproduce there.

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Russia astronauts have found bacteria living on the outside of ISS

8:42 am

Russia astronauts have found bacteria that was not intentionally brought into space living on the outside of ISS.

They are being studied on Earth but most likely they don’t pose any sort of danger, Russian cosmonaut Anton Shkaplerov told TASS on Monday. According to him, during spacewalks from the International Space Station under the Russian program, the cosmonauts took samples with cotton swabs from the station’s external surface. In particular, they took probes from places where the accumulation of fuel wastes were discharged during the engines’ operation or at places where the station’s surface is more obscure. After that, the samples were sent back to Earth.

“And now it turns out that somehow these swabs reveal bacteria that were absent during the launch of the ISS module. That is, they have come from outer space and settled along the external surface.”

I suspect it is a bit of hyperbole to say the bacteria came from outer space. It more likely came from either the station itself, or later spacecraft docking with the station. At the same time, the article is vague about what has been discovered. For example, it says nothing about the bacteria itself.

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A mission to interstellar object Oumuamua?

11:31 am

A private company and a volunteer group dedicated to promoting interstellar travel have written a paper [pdf] exploring the possibility of launching a mission to fly past the interstellar object Oumuamua, now speeding out of our solar system.

As they note in the paper’s abstract,

Can such objects be intercepted? The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess velocity of about 26 km/s; much faster than any vehicle yet launched. This paper presents a high-level analysis of potential near-term options for such a mission. Launching a spacecraft in a reasonable timeframe of 5-10 years requires a hyperbolic solar system excess velocity between 33 to 76 km/s for mission durations between 30 to 5 years. Different mission durations and their velocity requirements are explored with respect to the launch date, assuming direct impulsive transfer to the intercept trajectory. Several technology options are outlined, ranging from a close solar Oberth Maneuver using chemical propulsion, and the more advanced options of solar and laser sails. To maximize science return decelerating the spacecraft at ’Oumuamua is highly desirable, due to the minimal science return from a hyper-velocity encounter. It is concluded that although reaching the object is challenging, there seem to be viable options based on current and near-term technology.

The paper even considers the use of SLS or SpaceX’s Big Falcon Rocket.

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Nobel laureates demand Iran release scientist sentenced to death

8:57 am

Seventy-five Nobel laureates have written and signed a letter to the Iranian government demanding it release the Iranian scientist who it convicted of espionage and sentenced to death.

The group wrote to Gholamali Khoshroo, the Iranian ambassador to the United Nations, on 17 November, and the letter was made public on 21 November. The Nobel laureates express their concern for the conditions of Djalali’s detention; they deem his trial “unfair” and “flawed”, and they urge the Iranian authorities to let him return to Sweden, where he lived.

The list includes prominent names such as Harold Varmus, a former director of the US National Institutes of Health, now at the Weill Cornell Medicine institute in New York, and Andre Geim, a physicist based at the University of Manchester, UK. They wrote: “As members of a group of people and organizations who, according to the will of Alfred Nobel are deeply committed to the greatest benefit to mankind, we cannot stay silent, when the life and work of a similarly devoted researcher as Iranian disaster medicine scholar Ahmadreza Djalali is threatened by a death sentence.”

The scientist, Ahmadreza Djalali, lived in Sweden and was accused by Iran of spying for Israel. He in turn said the conviction was revenge for his refusal to spy for Iran.

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A spot on Mars, as seen by different orbiters over the past half century

9:29 am

Mars as seen over the past half century

The science team of Mars Reconnaissance Orbiter (MRO) have assembled a collection of images of the same location on Mars that were taken by different Martian orbiters, beginning with the first fly-by by Mariner 4 in 1965 and ending with MRO’s HiRise camera. The image on the right, reduced in resolution to post here, shows these images superimposed on that location, with resolutions ranging from 1.25 kilometers per pixel (Mariner 4) down to 50 meters per pixel (MRO).

This mosaic essentially captures the technological history of the first half century of space exploration in a single image. Mariner 4 was only able to take 22 fuzzy pictures during its fly-by. Today’s orbiters take thousands and thousands, with resolutions so sharp they can often identify small rocks and boulders.

The mosaic also illustrates well the uncertainty of science. When Mariner 4 took the first pictures some scientists thought that there might be artificially built canals on Mars. Instead, the probe showed a dead cratered world much like the Moon. Later images proved that conclusion to be wrong as well, with today’s images showing Mars to be a very complex and active world, with a geological history both baffling and dynamic. Even now, after a half century of improved observations, we still are unsure whether life there once existed, or even if exists today.

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New study says recurring dark streaks on Mars are from flowing sand, not water

9:49 am

The uncertainty of science: A new study has concluded that the recurring dark streaks on Martian slopes are caused not from flowing seeps of water but from small sand avalanches.

Continuing examination of these still-perplexing seasonal dark streaks with a powerful camera on NASA’s Mars Reconnaissance Orbiter (MRO) shows they exist only on slopes steep enough for dry grains to descend the way they do on faces of active dunes.

The findings published today in Nature Geoscience argue against the presence of enough liquid water for microbial life to thrive at these sites. However, exactly how these numerous flows begin and gradually grow has not yet been explained. Authors of the report propose possibilities that include involvement of small amounts of water, indicated by detection of hydrated salts observed at some of the flow sites.

The results do not exclude the possibility that water plays a part, but do suggest it plays a much smaller part, or none at all.

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Arecibo gets a backer to keep it running

10:59 pm

The National Science Foundation has found at least one backer to pick up the majority of the cost for running the Arecibo Observatory in Puerto Rico, thus keeping it operational.

For about a decade, the National Science Foundation, which owns the observatory and supplies about two-thirds of its $12 million budget, had been mulling downsizing or even shuttering the telescope to free up funds for other projects. Instead, the NSF will continue scientific operations at the facility in collaboration with an unnamed partner organization, according to a Record of Decision signed this week.

Arecibo sustained $4 million to $8 million in damage during the hurricane, according James Ulvestad, acting assistant director for the agency’s mathematical and physical sciences directorate. Some scientists worried that would weaken the case for keeping the observatory operational.

But Ulvestad said the agency’s Record of Decision reflects that it has received viable partnership proposals from one or more collaborators — though he would not provide details about those proposals. This announcement allows the NSF to move forward with negotiations on a new management contract.

Under the new plan, the agency will reduce its annual contribution to the observatory from about $8.2 million to $2 million over the next five years. It is also committed to funding any repairs required to restore Arecibo to its pre-hurricane condition, Ulvestad said.

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Mars rover update: November 16, 2017

10:17 am

Summary: Curiosity does drill tests, crosses Vera Rubin Ridge. Opportunity finds evidence of either ice or wind scouring on rocks in Perseverance Valley.

Curiosity

For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.

Curiosity looks up Vera Rubin Ridge, Sol 1850

Since my last update on September 6, Curiosity has continued its travels up and across Vera Rubin Ridge, a geological bedding plain dubbed the Hematite Unit. The panorama above, created by reader Phil Veerkamp, shows the view looking up the ridge slope. If you click on it you can see the full resolution image, with lots of interesting geological details.

The panorama below, also created by Veerkamp, shows the view on Sol 1866, two weeks later, as the slope begins to flatten out and the distant foothills of Mount Sharp become visible. (If you click on the image you can see a very slightly reduced version of the full resolution panorama.) This image also shows the next change in geology. From orbit the Hematite Unit darkens suddenly at its higher altitudes, and Curiosity at this point was approaching that transition. The rover is now, on Sol 1876, sitting on that boundary, where they will spend a few days making observations before moving on.

Curiosity on the Hematite Unit, Sol 1866

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The image on the right shows Curiosity’s approximate position, about halfway across the Hematite Unit and with the rover’s approximate future route indicated, as shown in this October 3, 2016 press release.

In the two months since my last rover update the Curiosity engineering team has spent a lot of time imaging and studying the Hematite Unit. They have also spent a considerable amount of time doing new tests on the rover’s drill in an effort to get around its stuck feed mechanism in order to drill again. Only yesterday they took another series of close-up images of the drill in this continuing effort.

As indicated by the October 3 2016 press release, the rover still has a good way to go before it begins entering the distant canyons and large foothills. While they should leave the Hematite Unit and enter the Clay Unit beyond in only a few more months, I expect it will be at least a year before they pass through the Clay Unit and reach the much more spectacular Sulfate Unit, where the rover will explore at least one deep canyon as well as a recurring dark feature on a slope that scientists think might be a water seep.

Opportunity

For the context of Opportunity’s recent travels along the rim of Endeavour Crater, see my May 15, 2017 rover update.
» Read more

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Another LIGO black hole merger detected

8:47 am

Astronomers have announced another black hole merger detected by the LIGO gravitational wave observatory.

Dubbed GW170608, the latest discovery was produced by the merger of two relatively light black holes, 7 and 12 times the mass of the sun, at a distance of about a billion light-years from Earth. The merger left behind a final black hole 18 times the mass of the sun, meaning that energy equivalent to about 1 solar mass was emitted as gravitational waves during the collision.

This event, detected by the two NSF-supported LIGO detectors at 02:01:16 UTC on June 8, 2017 (or 10:01:16 pm on June 7 in US Eastern Daylight time), was actually the second binary black hole merger observed during LIGO’s second observation run since being upgraded in a program called Advanced LIGO. But its announcement was delayed due to the time required to understand two other discoveries: a LIGO-Virgo three-detector observation of gravitational waves from another binary black hole merger (GW170814) on August 14, and the first-ever detection of a binary neutron star merger (GW170817) in light and gravitational waves on August 17.

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Petroglyphs found depicting the earliest leashed dogs?

8:43 am

Archaeologists have found petroglyphs in Saudi Arabia that could be the earliest depiction of dogs being held by leashes.

Carved into a sandstone cliff on the edge of a bygone river in the Arabian Desert, a hunter draws his bow for the kill. He is accompanied by 13 dogs, each with its own coat markings; two animals have lines running from their necks to the man’s waist.

The engravings likely date back more than 8000 years, making them the earliest depictions of dogs, a new study reveals. And those lines are probably leashes, suggesting that humans mastered the art of training and controlling dogs thousands of years earlier than previously thought.

The dating however remains uncertain. The carvings could be much younger.

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Haze on Pluto lowers its global climate temperature 54º F

8:32 am

Using data collected during New Horizons’ fly-by, scientists have found that the planet’s atmosphere is 54º F colder than predicted, and from this they theorize that the presence of haze in that atmosphere is what cools it.

Pluto’s atmosphere is made mostly of nitrogen, with smaller amounts of compounds such as methane. High in the atmosphere — between 500 and 1,000 kilometres above the surface — sunlight triggers chemical reactions that transform some of these gases into solid hydrocarbon particles.

The particles then drift downward and, at around 350 kilometres above Pluto’s surface, clump with others to form long chemical chains. By the time they reach 200 kilometres’ altitude, the particles have transformed into thick layers of haze, which the New Horizons spacecraft saw dramatically blanketing Pluto.

Zhang and his colleagues compared the heating and cooling effects of the atmosphere’s gas molecules to those of its haze particles. Earlier studies have suggested that the presence of gas molecules, such as hydrogen cyanide, could help explain why Pluto’s atmosphere is so cold. But Zhang’s team found that including haze was the only way to get their model to match the temperatures that New Horizons measured as it flew by the dwarf planet.

This theory remains unproven. Moreover, there are other explanations proposed for the cold atmosphere by other scientists. It will take new instruments and future probes to resolve the question.

The post has been corrected. My math in calculating the conversion from Celsius to Fahrenheit was initially faulty. Thanks to reader Kirk for spotting the error.

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Interstellar object resembles asteroid

6:43 pm

Astronomers who have been observing the interstellar object that zipped past the Sun last month have concluded that it mostly resembles asteroids seen in our own solar system.

From its changing brightness, the team inferred that U1 is highly elongated with rough dimensions 30m x 30m x 180m. About twice the height of the Statue of Liberty, the 6:1 aspect ratio of U1 is “similar to the proportions of a fire extinguisher — although U1 is not as red as that,” says David Jewitt (UCLA), the first author of the study.

“With such an elongated shape, U1 probably needs a little cohesive strength to hold it together. But that’s not really unusual,” remarked study coauthor Jayadev Rajagopal (National Optical Astronomy Observatory). Commenting on its size, rotation, and color, Rajagopal mused that, “the most remarkable thing about U1 is that, except for its shape, how familiar and physically unremarkable it is.”

I wonder if they are still tracking it.

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Astronomers find habitable Earth-mass planet 11 light years away

9:15 am

Worlds without end: Astronomers have found an Earth-mass planet 11 light years away, orbiting a quiet red dwarf star in the habitable zone.

Unlike Proxima Centauri, which periodically has large flares which make its Earth-sized planet less hospitable to life, this red dwarf, Ross 128, is more stable.

Many red dwarf stars, including Proxima Centauri, are subject to flares that occasionally bathe their orbiting planets in deadly ultraviolet and X-ray radiation. However, it seems that Ross 128 is a much quieter star, and so its planets may be the closest known comfortable abode for possible life.

Although it is currently 11 light-years from Earth, Ross 128 is moving towards us and is expected to become our nearest stellar neighbour in just 79 000 years — a blink of the eye in cosmic terms. Ross 128 b will by then take the crown from Proxima b and become the closest exoplanet to Earth!

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Zwicky Transient Facility sees first light

10:54 am

Astronomers announced today that the Zwicky Transient Facility at the Palomar Observatory in California has seen first light, and will begin full operations in 2018.

When fully operational in 2018, the ZTF will scan almost the entire northern sky every night. Based at the Palomar Observatory in southern California and operated by Caltech, the ZTF’s goal is to use these nightly images to identify “transient” objects that vary between observations — identifying events ranging from supernovae millions of light years away to near-Earth asteroids.
an image of stars and the night sky

In 2016, the UW Department of Astronomy formally joined the ZTF team and will help develop new methods to identify the most “interesting” of the millions of changes in the sky — including new objects — that the ZTF will detect each night and alert scientists. That way, these high-priority transient objects can be followed up in detail by larger telescopes, including the UW’s share of the Apache Point Observatory 3.5-meter telescope.

By producing new high resolution images of the entire northern sky every night, this telescope instrument is going to discover gobs of new transients, from supernovae to binaries to novae to things we haven’t even seen before.

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