Tag: astronomy

Astronomers produce best image yet of a star

2:11 pm

The uncertainty of science: Astronomers have produced the best image so far of the surface face of a star.

The star is Antares, and it provides some details of the star’s complex outer layers. If I was home and had good internet access, I’d post it here.

At the same time, it should be noted that this is not a real image. It is recreated from four telescopes, using interferometry to combine the images, and also includes it a great deal of assumptions and uncertainties in its creation.

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To protect students from eclipse some schools will close Monday, or will keep their students indoors

9:54 am

The coming dark age: Fearful of the thunder gods, some school administrators have decided to close their schools or to keep their students indoors so they can’t see the eclipse on Monday.

CBS Miami reports some local schools in South Florida are giving kids an excused absence or even the day off to enjoy the eclipse, while others have decided to keep students inside for their safety.

The Scottsdale Unified School District in Arizona decided it was just too dangerous to let kids view the eclipse, especially after some reports of fake eclipse glasses on the market that might put eyes at risk, CBS Phoenix affiliate KPHO reports. “So without us being able to control the equipment that’s being used, if it’s donated or something, and also when you’re talking about a large amount of children it’s also very difficult to convince all of the kids to not look up. That’s not to say our kids won’t be very well behaved but if there’s even a question that there could be something unsafe, Scottsdale’s not going to take the chance,” said Erin Helm with Scottsdale Unified.

The quote is from the second link above. The first link describes the decision of Ohio schools to close.

It is horrifying that there are school officials out there who would actually act to prevent children from experiencing the eclipse out of fear. Kids are smart enough to know not to look at the Sun, if you tell them not to. And it is the responsibility of the school to provide them the right kinds of eclipse glasses, which do not cost a lot and can easily be purchased.

In fact, it is revealing that the schools doing this are all public schools, and thus provides more evidence that the public schools might be the worst place to send kids to get educated.

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“One of the greatest discoveries of the century is based on these things and we don’t even know what they are, really.”

9:42 am

The uncertainty of science: New research suggests that astronomers have little understanding of the supernovae that they use to estimate the distance to most galaxies, estimates they then used to discover dark energy as well as measure the universe’s expansion rate.

The exploding stars known as type Ia supernovae are so consistently bright that astronomers refer to them as standard candles — beacons that are used to measure vast cosmological distances. But these cosmic mileposts may not be so uniform. A new study finds evidence that the supernovae can arise by two different processes, adding to lingering suspicions that standard candles aren’t so standard after all.

The findings, which have been posted on the arXiv preprint server and accepted for publication in the Astrophysical Journal, could help astronomers to calibrate measurements of the Universe’s expansion. Tracking type Ia supernovae showed that the Universe is expanding at an ever-increasing rate, and helped to prove the existence of dark energy — advances that secured the 2011 Nobel Prize in Physics.

The fact that scientists don’t fully understand these cosmological tools is embarrassing, says the latest study’s lead author, Griffin Hosseinzadeh, an astronomer at the University of California, Santa Barbara. “One of the greatest discoveries of the century is based on these things and we don’t even know what they are, really.”

The key to understanding this situation is to maintain a healthy skepticism about any cosmological theory or discovery, no matter how enthusiastically touted by the press and astronomers. The good astronomers do not push these theories with great enthusiasm as they know the feet of clay on which they stand. The bad ones try to use the ignorant mainstream press to garner attention, and thus funding.

For the past two decades the good astronomers have been diligently checking and rechecking the data and the supernovae used to discover dark energy. Up to now this checking seems to still suggest the universe’s expansion is accelerating on large scales. At the same time, our knowledge of supernovae remains sketchy, and thus no one should assume we understand the universe’s expansion rate with any confidence.

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Ten planetary probes track a solar eruption through the solar system

9:02 am

The path of an October 2014 solar eruption was tracked by ten different spacecraft, including Curiosity on the surface of Mars, as its blast moved outward through the solar system.

The measurements give an indication of the speed and direction of travel of the CME [Coronal Mass Ejection], which spread out over an angle of at least 116 degrees to reach Venus Express and STEREO-A on the eastern flank, and the spacecraft at Mars and Comet 67P Churyumov–Gerasimenko on the western flank.

From an initial maximum of about 1000 kilometers per second (621 miles per second) estimated at the sun, a strong drop to 647 kilometers per second (402 miles per second) was measured by Mars Express three days later, falling further to 550 kilometers per second (342 miles per second) at Rosetta after five days. This was followed by a more gradual decrease to 450–500 kilometers per second (280-311 miles per second) at the distance of Saturn a month since the event.

The CME was first detected by solar observatories Proba-2, SOHO, Solar Dynamics Observatory, and STEREO-A.It was then tracked as it moved outward by Venus Express, Mars Express, MAVEN, Mars Odyssey, Curiosity, Rosetta, Cassini, and even New Horizons and Voyager 2.

On my last appearance on Coast to Coast, I was specifically asked if the probes to Venus, Mars, and other planets have the capability to track solar events. I knew that the Voyager spacecraft had equipment to do this, but was unsure about other planetary probes. This article answers that question.

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Amazon refunding customers who bought fake eclipse glasses

9:43 am

Amazon is issuing refunds to any customers who bought fake eclipse glasses through the site.

It is essential for people who are going to view the eclipse to understand that as long as the Sun is even partially visible, even by a sliver, it can cause significant eye damage if viewed without proper protection. Make sure your eclipse glasses or filters are safe! And remember, only during the short 2 minute or so totality that will occur in the narrow strip across the country will it be safe to look at the Sun without protection. Even so, you must do so with great caution so that you don’t mistakenly view the Sun unprotected when it is partially exposed.

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Unexpected big storm on Neptune

9:17 am

The uncertainty of science: Astronomers have spotted a new very big storm on Neptune, occurring unexpectedly near the plane’s equator.

A large, high-pressure vortex system deep within Neptune’s atmosphere is thought to drive the white storm clouds. As methane gases rise up in the vortex, they cool below the condensation temperature, forming clouds in the same way that water vapor does on Earth.

The location of the vortex caught astronomers by surprise, though. “Historically, bright clouds have occasionally been seen on Neptune, but usually at latitudes closer to the poles, around 10 to 60 degrees north or south” says de Pater. “Never before has a cloud been seen at, nor close to the equator, or anything so bright.”

Neptune is the windiest planet in the solar system, with observed equatorial wind speeds of up to 1,000 miles per hour (450 m/s). Since wind speeds vary drastically with latitude, a storm crossing more than 30° of latitude should quickly break apart. Something, such as an underlying vortex, must be holding it together. But a long-lasting vortex right at the equator would be hard to reconcile with our current understanding of the planet’s atmosphere.

I think any theory about Neptune’s weather should treated with a great deal of skepticism. I am sure the theories are based on what is known, but what is known is very little. Until we have been able to observe this gas giant up close and for decades, our understanding of its weather is going to be sketchy, at best.

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Chinese engineers and astronomers fight over new telescope design

9:10 am

A dispute over the design of a new Chinese optical telescope has broken out between the astronomers who will use it and the engineers who will build it.

In April, an international committee convened by [Chinese Academy of Science’s] Center for Astronomical Mega-Science, which is responsible for the project, reviewed the competing designs and recommended the three-mirror option [the preference of astronomer Jiansheng Chen and China’s astronomers]. On 10 July, [Xiangqun Cui, the instrument’s chief engineer] organized her own review committee that picked the SYZ design as better. Cui’s panel “leaned toward one side,” Chen says. And one member says that the three-mirror design was not sufficiently presented, partly because no one from the Huazhong team was there. Cui and Su explain in their open letter that a member of their own group who knows it well introduced the Huazhong design. “Members were repeatedly reminded they could abstain from voting,” they write. One-third of the 21 committee members did abstain.

Meanwhile, to date, more than 130 young astronomers have signed an open letter to the astronomical community urging that the recommendations of the international panel be respected.

The fundamental disagreement, according to Chen, is “whether a large science project should be technically or scientifically oriented.” Cui and Su say the choice is between incorporating “rapidly developing new technologies” that ensure a long life for the facility, or “simply replicating a 10-meter telescope built 30 years ago.”

This spat reinforces the impression gained from the recent other story about China’s inability to find a manager for its newly built radio telescope. Its top-down management approach (where decisions are made by well-connected powerful bureaucrats at the top of the chain of command) produces office politics that generally does not lead to good technical decisions.

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China has a giant radio telescope and no one to run it

9:04 am

China’s effort to become a major player in the astronomy and space exploration field has run up against a strange problem.

China has built a staggeringly large instrument in the remote southern, mountainous region of the country called the Five hundred-meter Aperture Spherical Telescope, or FAST. The telescope measures nearly twice as large as the closest comparable facility in the world, the US-operated Arecibo radio telescope in Puerto Rico. Radio telescopes use a large, parabolic dish to collect radio waves from distant sources, such as pulsars and black holes—or even alien civilizations.

According to the South China Morning Post, the country is looking for a foreigner to run the observatory because no Chinese astronomer has the experience of running a facility of such size and complexity. The Chinese Academy of Sciences began advertising the position in western journals and job postings in May, but so far there have been no qualified applicants.

Part of the problem here is that it appears the telescope was built by order of the Chinese government, not Chinese astronomers. It would have been better for China to have built something its own astronomers were qualified to run. Instead, they built something to impress the world, and now can’t find a way to use it.

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Hawaiian protesters fail to block mirror for solar telescope

11:21 pm

The coming dark age: Protesters today tried, and failed, to block the delivery of the primary mirror of a new solar telescope being built on top of Haleakalā on the island of Maui.

Protesters chanted, sang, marched, and blocked the road with two bamboo altars on which they presented offerings of flowers and garlands in a traditional ceremony. Police stood by for about an hour, periodically coming forward to talk with protest organizers.

At 4 a.m., they moved in to clear the road. Protesters were lying down in the road with their arms linked. Police lifted them out of the way to allow the trucks to pass. Several men then rushed forward and threw themselves in front of and under the massive trucks. Police removed the men, along with several others, as protesters shouted, “auwe” (alas), and “shame.” Organizers say three men and two women were arrested.

I think this quote from one of the protest organizers (who happens to be an assistant professor of Hawaiian Studies & Language at the University of Hawaii, epitomizes their movement:

Earlier in the evening, organizer Kahele Dukelow vowed to continue to oppose future construction and to ultimately bring existing telescopes down. “This struggle is going to go on for generations. It’s not going to stop with us,” she told protesters. “We will never accept it.”

Apparently the idea of gaining knowledge about the universe is unacceptable to this college professor and her allies. Such knowledge is evil, and must be blocked at all cost. The only knowledge that matters is the ethnic race heritage of native Hawaiians, no matter how primitive and uncivilized.

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Cameras on next Kepler-like exoplanet space telescope out of focus

9:34 am

NASA has revealed that the cameras on the Transiting Exoplanet Survey Satellite (TESS) become slightly out of focus when they are cooled to -75 Celsius, the temperature they will experience in space.

NASA has also decided that the fuzziness is not enough to require a fix, and is proceeding with the mission as is, despite concerns expressed by scientists.

Alan Boss, an astronomer with the Carnegie Institution, brought up the issue in a summary of a meeting last week of the Astrophysics Advisory Committee, of which he is a member. “That could have some big effects on the photometry,” he said of the focus problem. “This is certainly a concern for the folks who know a lot about photometry.”

TESS will use those cameras to monitor the brightness of the nearest and brightest stars in the sky, an approach similar to that used by Kepler, a spacecraft developed originally to monitor one specific region of the sky. Both spacecraft are designed to look for minute, periodic dips in brightness of those stars as planets pass in front of, or transit, them. Chou said that since TESS is designed to conduct photometry, measuring the brightness of the stars in its field of view, “resolution is less important compared to imaging missions like Hubble.” However, astronomers are concerned that there will be some loss of sensitivity because light from the stars will be spread out onto a slightly larger area of the detector.

“The question is how much science degradation will there be in the results,” Boss said. “The TESS team thinks there will be a 10 percent cut in terms of the number of planets that they expect to be able to detect.”

It could be that NASA has decided that the cost and delay required to fix this is not worth that 10% loss of data.

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Judge okays TMT permit

9:14 am

In a 305-page decision, an Hawaiian judge has approved a new construction permit for the Thirty Meter Telescope (TMT) on Mauna Kea.

This does not mean that the project now proceeds.

This isn’t the final say on whether the embattled project will proceed.

Now that Amano has issued her 305-page proposed decision and order, the state land board will set a deadline for telescope opponents and permit applicants to file arguments against her recommendations. The board will later hold a hearing and then make the final decision on the project’s conservation district use permit.

Not surprisingly, the Democratic governor of Hawaii issued a short, non-committal statement, stating that he supports “the co-existence of astronomy and culture on Mauna Kea,” whatever that means.

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Astronomers find unexpected comets in outer reaches of solar system

11:49 am

Using data from the WISE space telescope, astronomers have found that there are more comets lurking in the far reaches of the solar system than they had predicted.

Scientists found that there are about seven times more long-period comets measuring at least 0.6 miles (1 kilometer) across than had been predicted previously. They also found that long-period comets are on average up to twice as large as “Jupiter family comets,” whose orbits are shaped by Jupiter’s gravity and have periods of less than 20 years. Researchers also observed that in eight months, three to five times as many long-period comets passed by the Sun than had been predicted.

These are comets whose orbits never allow them to come close to the inner solar system, which allows them to remain puffy and large.

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Hubble shoots movie of Phobos

10:34 am

Phobos over Mars

Cool image time! By taking a quick series of thirteen images, the Hubble Space Telescope was able to shoot a short movie of the rotation of Phobos above the surface of Mars. The gif animation on the right is the smaller of the two animations released today. Be sure and view the full resolution version.

What is even cooler is that movie was apparently unplanned. From the link:

Over the course of 22 minutes, Hubble took 13 separate exposures, allowing astronomers to create a time-lapse video showing the diminutive moon’s orbital path. The Hubble observations were intended to photograph Mars, and the moon’s cameo appearance was a bonus.

In terms of science this movie has a somewhat limited value. In terms of space engineering it is triumph, and once again illustrates the unprecedented value of having an optical telescope in space. Woe to us all when Hubble finally dies, as we have no plans to replace it.

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China’s giant single dish radio telescope FAST nears completion

10:19 am

The new colonial movement: The completion of FAST, the world’s largest single dish radio telescope in China, nears completion.

The article over emphasizes one of the telescope’s minor research projects, the search for alien life. However, it also provides a good overview of the telescope’s status. The main dish is finished, and they are presently building the instruments that will use that dish to do astronomical research.

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NASA and JAXA approve replacement of failed Japanese X-ray space telescope

10:39 am

NASA and JAXA have agreed to build a replacement for the Japanese Hitomi X-ray space telescope that failed after only a few weeks in orbit in March 2016.

The X-ray Astronomy Recovery Mission, or XARM, could launch as soon as March 2021, filling a potential gap in astronomers’ X-ray vision of the universe, according to the Japan Aerospace Exploration Agency, or JAXA. NASA has agreed to a junior partner in XARM — pronounced “charm” — and supply X-ray telescopes and a spectrometer instrument for the Japanese-led mission, according to Paul Hertz, directory of NASA’s astrophysics division.

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New Horizons’ next target might be smaller than predicted

10:43 am

The uncertainty of science: Because all attempts to observe an occultation of a star on June 3 by New Horizons’ next target failed, astronomers now think Kuiper Belt object 2014 MU69 is much smaller than previously believed.

The discovery observations using Hubble and other ground-based telescopes had estimated its size as between 12 to 25 miles in diameter. The null result from the June 3 event suggests it is smaller than that.

More occultations are upcoming, so stay tuned.

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Fastest stars in Milky Way escaped from Large Magellanic Cloud?

9:01 am

Astronomers have proposed that the fastest stars in Milky Way actually escaped from the Large Magellanic Cloud (LMC), the largest nearby satellite dwarf galaxy.

The LMC is the largest and fastest of the dozens of dwarf galaxies in orbit around the Milky Way. It only has 10% of the mass of the Milky Way, and so the fastest runaways born in this dwarf galaxy can easily escape its gravity. The LMC flies around the Milky Way at 400 kilometres per second and, like a bullet fired from a moving train, the speed of these runaway stars is the velocity they were ejected at plus the velocity of the LMC. This is fast enough for them to be the hypervelocity stars. “These stars have just jumped from an express train – no wonder they’re fast,” said co-author Rob Izzard, a Rutherford fellow at the Institute of Astronomy. “This also explains their position in the sky, because the fastest runaways are ejected along the orbit of the LMC towards the constellations of Leo and Sextans.”

Their calculations predict how many hypervelocity stars should be detectable and where in the sky they should be. If right, the data from Gaia, soon to be released, should prove them right or wrong.

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Astronomers take best image of Betelgeuse yet

5:21 pm

Betelqeuse

Using the Atacama Large Millimeter/submillimeter Array Telescope (ALMA), astronomers have produced the best picture of the red giant star Betelgeuse taken so far.

Using ESO’s Very Large Telescope astronomers discovered a vast plume of gas almost as large as our Solar System. Astronomers have also found a gigantic bubble that boils away on Betelgeuse’s surface. These features help to explain how the star is shedding gas and dust at tremendous rates (eso0927, eso1121). In this picture, ALMA observes the hot gas of the lower chromosphere of Betelgeuse at sub-millimeter wavelengths — where localised increased temperatures explain why it is not symmetric.

The image on the right is that image, slightly reduced to post here. The bulge on the star’s left illustrates the unevenness of the star’s upper atmosphere. I suspect that continuous observations would reveal the outer atmosphere waxing and waning almost like the stuff inside a lava lamp.

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Astronomers discover complex molecules in protostar accretion disk

10:18 am

Astronomers have discovered several complex molecules in the accretion disk surrounding a very young baby star about 1300 light years away in the constellation Orion.

The research team’s ALMA observations have clearly detected an atmosphere of complex organic molecules above and below the disk. These include methanol (CH3OH), deuterated methanol (CH2DOH), methanethiol (CH3SH), and formamide (NH2CHO). These molecules have been proposed to be the precursors for producing biomolecules such as amino acids and sugars. “They are likely formed on icy grains in the disk and then released into the gas phase because of heating from stellar radiation or some other means, such as shocks,” says co-author Zhi-Yun Li of the University of Virginia.

What is even most interesting about this discovery is that these complex molecules are not scattered throughout the disk, but are concentrated in regions above and below its central plane, what the astronomers are labeling “an atmosphere.” This suggests that differentiation — the same process that separates the heavier molecules from lighter ones both in centrifuges and in the cores of planets — occurs quickly in accretion disks as well.

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Uranus’s magnetic field switches on and off daily

9:54 am

Using data from the Voyager 2 flyby of Uranus in 1986, scientists now think that the gas giant’s magnetic field switches on and off each day as the planet rotates.

Uranus’s magnetosphere, in contrast [to Earth], exhibits precise regularity in its mode changes. This, say the researchers, is because it lies at an angle of roughly 60 degrees to the planet’s spin axis, causing its interaction with incoming solar winds to vary dramatically during the 17 hours it takes for a full rotation. “Uranus is a geometric nightmare,” says Paty.

“The magnetic field tumbles very fast, like a child cartwheeling down a hill head over heels. When the magnetised solar wind meets this tumbling field in the right way, it can reconnect and Uranus’s magnetosphere goes from open to closed to open on a daily basis.”

The researchers suggest the robust and regular changes to the magnetosphere may mean that the icy planet has spectacular auroras across its breadth every day.

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