Tag: astronomy

Hubble captures on-going comet break-up

10:47 am

animation of comet debris

Cool image time! The animation to the right, taken over three days by the Hubble Space Telescope, cropped and reduced to fit here, shows the debris flying away from Comet 332P/Ikeya-Murakami. It also shows a new piece of debris close to the comet on the lower left.

The research team calculated that the comet probably shed material over several months, between October and December 2015. Jewitt suggests that even some of the ejected pieces have themselves fallen to bits in a kind of cascading fragmentation. “Our analysis shows that the smaller fragments are not as abundant as one might expect based on the number of bigger chunks,” he said. “This is suggestive that they’re being depleted even in the few months since they were launched from the primary body. We think these little guys have a short lifetime.”

Hubble’s sharp vision also spied a chunk of material close to the comet, which may be the first salvo of another outburst. The remnant from still another flare-up, which may have occurred in 2012, is also visible. The fragment may be as large as Comet 332P, suggesting the comet split in two. But the icy remnant wasn’t spotted until Dec. 31, 2015, by the Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) telescope in Hawaii, in work supported by the Near-Earth Object Observations program in NASA’s Planetary Defense Coordination Office. That discovery prompted Jewitt and colleagues to request Hubble time to look at the comet in detail. Around the same time, astronomers around the world began to notice a cloudy patch of material near the comet – which Hubble later resolved into the 25 pieces.

The scientists think they actually “may be seeing a comet fragmenting itself into oblivion.”

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NASA extends Hubble contract through 2021

5:00 pm

NASA has extended its contract with Lockheed Martin for the operation of the Hubble Space Telescope until June 2021.

This contract is for non-science operations. Science operations are controlled by the Space Telescope Science Institute in Baltimore.

Note that when the last repair mission to Hubble took place in 2009, they expected it to add five years to the telescope’s life. This contract says they now expect it to last at least until 2021, which will also be 31 years after its launch and almost forty years since its actual construction. Not a bad track record when you think about it, especially since its original mission was set at 15 years, ending in 2005.

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Scientists discover exoplanets orbiting both stars of binary system

9:46 am

Worlds without end: Scientists have discovered a stellar binary system which has giant exoplanets orbiting each of the system’s stars.

The twin stars studied by the group are called HD 133131A and HD 133131B. The former hosts two moderately eccentric planets, one of which is, at a minimum, about 1 and a half times Jupiter’s mass and the other of which is, at a minimum, just over half Jupiter’s mass. The latter hosts one moderately eccentric planet with a mass at least 2.5 times Jupiter’s.

The two stars themselves are separated by only 360 astronomical units (AU). One AU is the distance between the Earth and the Sun. This is extremely close for twin stars with detected planets orbiting the individual stars. The next-closest binary system that hosts planets is comprised of two stars that are about 1,000 AU apart.

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New and very distance outer solar system objects beyond Neptune

10:11 am

Astronomers have discovered several new objects orbiting the Sun at extremely great distances beyond the orbit of Neptune.

The most interesting new discovery is 2014 FE72:

Another discovery, 2014 FE72, is the first distant Oort Cloud object found with an orbit entirely beyond Neptune. It has an orbit that takes the object so far away from the Sun (some 3000 times farther than Earth) that it is likely being influenced by forces of gravity from beyond our Solar System such as other stars and the galactic tide. It is the first object observed at such a large distance.

This research is being done as part of an effort to discover a very large planet, possibly as much as 15 times the mass of Earth, that the scientists have proposed that exists out there.

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More details about Proxima Centauri’s Earthlike exoplanet

8:50 am

Link here. Lots of background into the discovery itself, but I think these paragraphs really sum things up:

“The search for life starts now,” says Guillem Anglada-Escudé, an astronomer at Queen Mary University of London and leader of the team that made the discovery.

Humanity’s first chance to explore this nearby world may come from the recently announced Breakthrough Starshot initiative, which plans to build fleets of tiny laser-propelled interstellar probes in the coming decades. Travelling at 20% of the speed of light, they would take about 20 years to cover the 1.3 parsecs from Earth to Proxima Centauri.

Proxima’s planet is at least 1.3 times the mass of Earth. The planet orbits its red-dwarf star — much smaller and dimmer than the Sun — every 11.2 days. “If you tried to pick the type of planet you’d most want around the type of star you’d most want, it would be this,” says David Kipping, an astronomer at Columbia University in New York City. “It’s thrilling.”

The human race now has a real interstellar target to aim for. Don’t be surprised if we get there sooner than anyone predicts.

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TMT will probably not go to India

10:04 am

An Indian astronomer, in testimony to India’s parliament, has explained that for engineering and technical reasons India will likely not be the new location of the Thirty Meter Telescope (TMT).

Essentially, the skies are clearer in the Canary Islands and in Chile.

This story is important in that it confirms that the consortium building TMT is now very seriously considering abandoning Hawaii, and might already have decided to do so. It also suggests that the Canary Islands is in the lead as the new location, since they want a site that can see the skies of the northern hemisphere, something that won’t be possible in Chile.

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Physicists fail to find sterile neutrino

9:02 am

The uncertainty of science: A year’s collection of data using IceCube, a gigantic neutrino telescope built in the icecap of Antarctica, has found no evidence of a theorized fourth type of neutrino.

To search for sterile neutrinos, Halzen’s team looked for the arrival of muon neutrinos that started life on the other side of Earth. These were originally produced by the collision of cosmic rays with air molecules in the atmosphere, and passed through the planet to reach the detector. The IceCube team hoped to find a dearth of muon neutrinos at particular energies. That would have suggested that some muon neutrinos had temporarily mutated into sterile neutrinos during their voyage.

But, after analysing the results of a year’s worth of data, the researchers found no feature suggesting the existence of sterile neutrinos around 1 eV. This is line with results from the European Space Agency’s Planck observatory, which concluded from cosmological evidence that there should only be three families of neutrinos in that mass range. “I hope that with our result and with the Planck result we are slowly walking our way back from this story,” says Halzen. The IceCube team are still taking data in their sterile neutrino hunt, but don’t expect their results to change, he adds.

Despite this null result, there is still a possibility that sterile neutrinos exist, but not at the mass predicted.

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A big Perseid meteor shower on Friday?

8:29 am

According to a new computer model of the Perseid meteor shower, astronomers predict that there could be a big peak of shooting stars on Friday.

Russian astronomer Mikhail Maslov and Finnish astronomer Esko Lyytinen predict that this year the Earth will pass through a stream of cometary material shifted towards us by Jupiter’s gravitational field. According to their model, and work by French scientist Jeremie Vaubaillon, we could see a steep rise in activity from late evening on 11 August to 0500 BST on 12 August.

The Perseids are typically active from around 17 July to 24 August, although for most of that period only a few meteors an hour will be visible. During the peak, and if the predictions by Maslov, Lyytinen and Vaubaillon are right, as many as 100 meteors or more may be seen each hour. This year, the light from the waxing gibbous Moon will interfere to some extent for the first part of the night, so observers are advised to look out in the early morning hours after midnight when the Moon is very low in the sky or has set.

If this is true, Diane and I might have lucked out, as we will be heading for our annual Grand Canyon hike to the bottom on Friday.

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The mystery of Tabby’s Star deepens

11:15 pm

The uncertainty of science: New data from Kepler has made it even more difficult for scientists to explain the strange fluctuations and dimming of Tabby’s Star.

KIC 8462852, as it is more properly known, flickers so erratically that one astronomer has speculated that nothing other than a massive extraterrestrial construction project could explain its weird behaviour. A further look showed it has been fading for a century. Now, fresh analysis suggests the star has also dimmed more rapidly over the past four years – only adding to the enigma. “It seems that every time someone looks at the star, it gets weirder and weirder,” says Benjamin Montet at the California Institute of Technology, who led the study.

There are as yet no natural explanations for the star’s dimming.

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Poll shows Hawaiians strongly favor TMT

11:14 pm

A new poll shows that by a 2 to 1 margin Hawaiians are in favor of building the Thirty Meter Telescope (TMT).

  • 89 percent of Hawaii Island residents agree there should be a way for science and Hawaiian culture to co-exist on Maunakea
  • 76 percent of Hawaii Island residents agree that TMT will help create good paying jobs and economic and educational benefits for those living on Hawaii Island
  • 70 percent of Hawaii Island residents agree that failure to move forward with TMT will hurt educational opportunities for Hawaii Island children with the termination of TMT’s annual $1 million contribution to the THINK Fund and workforce pipeline program
  • 69 percent of Hawaii Island residents agree that TMT has followed a lengthy approval process, so work should proceed

Based on what I’ve seen for the past forty years, this poll will mean nothing. The poll also found that the native Hawaiian population was much less supportive, with only 46 percent in support of the project and 45 percent opposed. And since the Democratic Party that runs Hawaii is a party that cares almost exclusively for the concerns of oppressed minorities over that of the non-native majority, you can bet they will do what the native population wants. The telescope will never get built in Hawaii, and the consortium building TMT had better face this reality and find another location.

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Astrobiologists meet to better their search for exoplanet life

9:25 am

The uncertainty of science: Astrobiologists are meeting this week in Seattle to discuss and refine their methods for detecting astrobiology on exoplanets.

The Seattle meeting aims to compile a working list of biosignature gases and their chemical properties. The information will feed into how astronomers analyse data from NASA’s James Webb Space Telescope, slated for launch in 2018. The telescope will be able to look at only a handful of habitable planets, but it will provide the first detailed glimpse of what gases surround which world, says Nikole Lewis, an astronomer at the Space Telescope Science Institute in Baltimore, Maryland.

No single gas is likely to be a slam-dunk indicator of alien life. But Domagal-Goldman hopes that the workshop will produce a framework for understanding where scientists could trip themselves up. “We don’t want to have a great press release,” he says, “and then a week later have egg on everybody’s faces.”

A few years ago I was told by one astronomer that the field’s biggest and most exciting area of research in the coming decades will be the effort to study the thousands exoplanets they only just discovered. I agree. The Webb telescope might have been built to study cosmology, but the data it will produce about exoplanets will be much more real and less uncertain, thus making it more compelling and convincing.

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“They can’t be real.”

8:56 am

The uncertainty of science: Astronomers have now detected and measured a new class of large but very dim galaxy that previously was not expected to exist.

‘Ultradiffuse’ galaxies came to attention only last year, after Pieter van Dokkum of Yale University in New Haven, Connecticut, and Roberto Abraham of the University of Toronto in Canada built an array of sensitive telephoto lenses named Dragonfly. The astronomers and their colleagues observed the Coma galaxy cluster 101 megaparsecs (330 million light years) away and detected 47 faint smudges.

“They can’t be real,” van Dokkum recalls thinking when he first saw the galaxies on his laptop computer. But their distribution in space matched that of the cluster’s other galaxies, indicating that they were true members. Since then, hundreds more of these galaxies have turned up in the Coma cluster and elsewhere.

Ultradiffuse galaxies are large like the Milky Way — which is much bigger than most — but they glow as dimly as mere dwarf galaxies. It’s as though a city as big as London emitted as little light as Kalamazoo, Michigan.

More significantly, they have now found that these dim galaxies can be as big and as massive as the biggest bright galaxies, suggesting that, surprise!, there are a lot more stars and mass hidden out there and unseen than anyone had previously predicted.

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WIMP detector finds nothing

8:36 am

The uncertainty of science: A detector buried a mile underground so that it could only detect the predicted Weak Interacting Massive Particles (WIMP) thought to comprise dark matter has found nothing

Dark matter is thought to account for more than four-fifths of the mass in the universe. Scientists are confident of its existence because the effects of its gravity can be seen in the rotation of galaxies and in the way light bends as it travels through the universe, but experiments have yet to make direct contact with a dark matter particle. The LUX experiment was designed to look for weakly interacting massive particles, or WIMPs, the leading theoretical candidate for a dark matter particle. If the WIMP idea is correct, billions of these particles pass through your hand every second, and also through the Earth and everything on it. But because WIMPs interact so weakly with ordinary matter, this ghostly traverse goes entirely unnoticed.

…“We worked hard and stayed vigilant over more than a year and a half to keep the detector running in optimal conditions and maximize useful data time,” said Simon Fiorucci, a physicist at Berkeley Lab and Science Coordination Manager for the experiment. “The result is unambiguous data we can be proud of and a timely result in this very competitive field—even if it is not the positive detection we were all hoping for.”

This null result, which has its own uncertainties that require confirmation by another experimental test, places significant constraints on the possible nature of the dark matter particle, assuming it exists. And if confirmed, this result makes the hunt to explain the gravitational data of galaxy rotation, something that has been confirmed repeatedly, far more difficult.

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Nearby exoplanets have Earthlike atmospheres

10:58 am

Worlds without end: New data from Hubble suggests that two rocky exoplanets only 40 light years away have atmospheres more similar to Earth’s than to that of gas giants.

Specifically, they discovered that the exoplanets TRAPPIST-1b and TRAPPIST-1c, approximately 40 light-years away, are unlikely to have puffy, hydrogen-dominated atmospheres usually found on gaseous worlds. “The lack of a smothering hydrogen-helium envelope increases the chances for habitability on these planets,” said team member Nikole Lewis of the Space Telescope Science Institute (STScI) in Baltimore, Maryland. “If they had a significant hydrogen-helium envelope, there is no chance that either one of them could potentially support life because the dense atmosphere would act like a greenhouse.”

The actual make-up of these atmospheres remains unknown. Also, the central star, a red dwarf, is estimated to be about a half billion years old. Both the star’s make-up — red dwarfs are not as rich in elements as a G-type sun — and age do not provide much margin for the development of life.

Nonetheless, the new data increases again the likelihood that we will eventually find habitable worlds orbiting other stars, and we will find them in large numbers.

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TMT likely to abandon Hawaii

3:55 pm

Officials from the consortium that is building the Thirty Meter Telescope (TMT) have revealed that they are looking very seriously at alternative locations.

Officials behind the proposed Thirty Meter Telescope (TMT) are considering new locations for the $1.4bn facility, and expect to decide whether to opt for a new site early next year. The TMT is due to be built on Hawaii’s Mauna Kea mountain but, following protests from local residents, its building permit was revoked last December by the state’s Supreme Court. New locations that are being considered include Baja California in Mexico, the Canary Islands and Chile, as well as locations in India and China.

They claim that Hawaii is still their first choice, but if they don’t see any progress by summer in the permitting process, I expect them to tell Hawaii to go to hell (though not in those words) and pick somewhere else.

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A planet with three suns

3:18 pm

Astronomers, using instruments on the Very Large Telescope in Chile, have discovered an exoplanet that orbits around three suns.

Located about 340 light years from Earth in the constellation Centaurus, HD 131399Ab is believed to be about 16 million years old, making it one of the youngest exoplanets discovered to date, and one of very few directly imaged planets. With a temperature of 850 Kelvin (about 1,070 degrees Fahrenheit or 580 degrees Celsius) and weighing in at an estimated four Jupiter masses, it is also one of the coldest and least massive directly imaged exoplanets.

“HD 131399Ab is one of the few exoplanets that have been directly imaged, and it’s the first one in such an interesting dynamical configuration,” said Daniel Apai, an assistant professor of Astronomy and Planetary Sciences who leads a research group dedicated to finding and observing exoplanets at the UA.

“For about half of the planet’s orbit, which lasts 550 Earth-years, three stars are visible in the sky, the fainter two always much closer together, and changing in apparent separation from the brightest star throughout the year,” said Kevin Wagner, a first-year PhD student in Apai’s research group and the paper’s first author, who discovered HD 131399Ab. “For much of the planet’s year the stars appear close together, giving it a familiar night-side and day-side with a unique triple-sunset and sunrise each day. As the planet orbits and the stars grow further apart each day, they reach a point where the setting of one coincides with the rising of the other – at which point the planet is in near-constant daytime for about one-quarter of its orbit, or roughly 140 Earth-years.”

The orbit of the planet remains somewhat uncertain, and thus it might not be stable.

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New Hubble image of Crab Nebula

9:42 am

Crab Nebula

Cool image time! Scientists have released a new Hubble Space Telescope image taken of the innermost regions of the Crab Nebula, the remains of a supernova explosion that took place a thousand years ago in 1054.

On the right is a reduced resolution version of this new image. I have also cropped it to focus on the nebula’s center, where the pulsar is located. The circular concentric rings are exactly what they appear to be, ripples of energy spreading out from the pulsar. Back in 2002 Hubble took a series of images of the Crab Nebula over several days, which scientists then assembled into a movie showing these waves as they emanated out from the nebula’s center.

My only complaint with this beautiful new image is that they did not take a longer series of new exposures to create a longer movie, to better show the actual daily changes that the nebula undergoes. It seemed obvious to do then, and obvious to do now. Yet, it hasn’t happened.

The image download page for today’s release is here.

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Hubble images Jupiter and its aurora

9:03 am

Jupiter and its aurora

Cool image time! In anticipation of the arrival of Juno in orbit around Jupiter on July 4, scientists have released a spectacular image of Jupiter and its aurora, taken by the Hubble Space Telescope. The image on the right has been reduced slightly to fit on the webpage.

The main focus of the imaging is the aurora.

To highlight changes in the auroras, Hubble is observing Jupiter almost daily for several months. Using this series of far-ultraviolet images from Hubble’s Space Telescope Imaging Spectrograph, it is possible for scientists to create videos that demonstrate the movement of the vivid auroras, which cover areas bigger than the Earth.

Not only are the auroras huge in size, they are also hundreds of times more energetic than auroras on Earth. And, unlike those on Earth, they never cease. While on Earth the most intense auroras are caused by solar storms — when charged particles rain down on the upper atmosphere, excite gases, and cause them to glow red, green, and purple — Jupiter has an additional source for its auroras.

The strong magnetic field of the gas giant grabs charged particles from its surroundings. This includes not only the charged particles within the solar wind, but also the particles thrown into space by its orbiting moon Io, known for its numerous and large volcanos.

I have embedded below the fold one of the videos of the aurora, taken over time by Hubble. Quite amazing.
» Read more

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Moon discovered orbiting Kuiper Belt Object Makemake

6:57 pm

Worlds without end: Astronomers have discovered a moon orbiting Makemake, the fouth largest object in the Kuiper Belt.

A nearly edge-on orbital configuration helped it evade detection, placing it deep within the glare of the icy dwarf during a substantial fraction of its orbit. Makemake is one of the largest and brightest known Kuiper Belt Objects (KBOs), second only to Pluto. The moon is likely less than 100 miles wide while its parent dwarf planet is about 870 miles across. Discovered in 2005, Makemake is shaped like football and sheathed in frozen methane.

Tracking this moon’s orbit will help astronomers get a better understanding of Makemake itself, whose oblong shape has baffled them since its discovery.

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Newly discovered asteroid quasi-moon of Earth

11:41 pm

A newly discovered asteroid has a solar orbit that makes it Earth’s constant companion.

As it orbits the sun, this new asteroid, designated 2016 HO3, appears to circle around Earth as well. It is too distant to be considered a true satellite of our planet, but it is the best and most stable example to date of a near-Earth companion, or “quasi-satellite.”

“Since 2016 HO3 loops around our planet, but never ventures very far away as we both go around the sun, we refer to it as a quasi-satellite of Earth,” said Paul Chodas, manager of NASA’s Center for Near-Earth Object (NEO) Studies at the Jet Propulsion Laboratory in Pasadena, California. “One other asteroid — 2003 YN107 — followed a similar orbital pattern for a while over 10 years ago, but it has since departed our vicinity. This new asteroid is much more locked onto us. Our calculations indicate 2016 HO3 has been a stable quasi-satellite of Earth for almost a century, and it will continue to follow this pattern as Earth’s companion for centuries to come.”

The asteroid is thought to be between 120 to 300 feet across.

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National Science Foundation considers shuttering Arecibo

9:33 am

Faced with tight budgets, the National Science Foundation (NSF) is considering several options for the future operation of the Arecibo Observatory, the world’s largest single radio telescope dish, including its complete removal.

[T]he NSF could mothball the site, shutting it down in such a way that it could restart (sometime in the future). Or it could dismantle the telescope altogether and restore the area to its natural state, as required by law if the agency fully divests itself of the observatory and closes it. Previous studies have said such a process could cost around $100 million—more than a decade’s worth of its current funding for telescope operations. Jim Ulvestad, director of the NSF Division of Astronomical Sciences, says the agency is still investigating, not concluding. “No alternative has been selected at this juncture,” he says. And much consideration will go into the final financial decision, whatever it may be. Some outside the agency see writing on the wall. “NSF is dead serious about offloading Arecibo funding to someone else—anyone else,” says Ellen Howell, a former staff scientist at Arecibo and now a faculty member at the Lunar and Planetary Laboratory (LPL) in Tucson, Arizona.

The article spends a lot of time talking about how wonderful Arecibo is, but never tells us how many astronomers actually demand to use it. Is it oversubscribed, like Hubble, where five times the number of astronomers request time than can be handled, or does it often sit unused because not enough astronomers require its use? NSF and the government do not have unlimited funds, and need to focus their spending where the demand is. If Arecibo is not in demand, then they are wise to consider closing it, or handing it off to someone who wants it.

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LISA Pathfinder proves space-based gravity wave detection technology

8:43 am

Engineers have announced that the gravity wave detection technology being tested in orbit by Europe’s LISA Pathfinder works.

To show that the necessary sensitivity is possible, LISA Pathfinder measures the distance between two masses, both of which are inside the spacecraft. “We’ve shrunk the arm of a large gravitational wave antenna to 35 centimeters so we could show it works properly,” Paul McNamara, LISA Pathfinder project scientist, told the press conference.

LISA Pathfinder was launched in December 2015 to a spot 1.5 million kilometers from Earth. When its test masses where first released to float free in February, “the relief was unbelievable,” McNamara says. Science operations began on 1 March and on that first day the team was able to measure distance variations between the masses much smaller than LISA Pathfinder’s mission requirements, Stefano Vitale, the mission’s principle investigator, told reporters. After a month, the variations were even smaller, “very close to [eLISA] requirements,” he says.

They now hope to launch an array of at least three such spacecraft by the mid-2030s.

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Titan over Saturn’s rings

9:35 am

Titan over Saturn's rings

Cool image time! The picture on the right, taken on January 26, 2016 by Cassini and reduced and cropped to show here, captures Titan above Saturn’s rings, which are themselves partly obscured by the shadow of Saturn (unseen on the right) that falls across them.

Make sure you go to look at the full image. This is the kind of vista that artists in the 1950s imagined we’d see once we began to explore the solar system.

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Hawaii turns down requests to remove TMT hearings officer

9:10 am

The state of Hawaii has decided to not replace the hearings officer in charge of the new permitting process for the Thirty Meter Telescope, despite a request by TMT to remove her.

There are different reasons for wanting to replace her. Telescope opponents raise conflict-of-interest concerns over her paid family membership to the Imiloa Astronomy Center. The university takes issue with her mediating another matter involving the Manoa campus. The nonprofit telescope company says replacing her with an alternate would avoid further delay.

“With due respect and consideration to the parties’ various interests and reasons for asking the board to replace Judge Amano, the board cannot and will not sidestep its own administrative responsibility to exercise judgment and common sense regarding whether the selection process up until now has objectively appeared to be fair,” the order said. “Common sense must prevail.”

The situation is a strange one. Despite the fact that the judge would likely rule fairly, TMT wanted her removed because they expect their opponents to eventually dispute any favorable decision she makes because of her link to the astronomy center. By refusing to remove her, the state is actually taking the side of the telescope’s opponents, since their main tactic is delay.

I hope TMT’s builders are making serious plans for finding an alternative site. I do not expect them to ever get permission to build in Hawaii.

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New data challenges consensus on galaxy formation

8:54 am

The uncertainty of science: A new study has found that the accepted consensus for the formation of large elliptical galaxies does not work, and that, rather than forming from the merger of smaller spiral galaxies, ellipticals formed in place from the material at hand.

From the press release [pdf].

“We started from the data, available in complete form only for the closer galaxies and in incomplete form for the more distant ones, and we filled the ‘gaps’ by interpreting and extending the data based on a scenario we devised” comments Mancuso. The analysis also took into account the phenomenon of gravitational lensing, which allows us to observe very distant galaxies belonging to ancient cosmic epochs.

In this “direct” manner (i.e., model-independent) the SISSA group obtained an image of the evolution of galaxies even in very ancient epochs (close, in a cosmic timescale, to the epoch of reionization). This reconstruction demonstrates that elliptical galaxies cannot have formed through the merging of other galaxies, “simply because there wasn’t enough time to accumulate the large quantity of stars seen in these galaxies through these processes”, comments Mancuso. “This means that the formation of elliptical galaxies occurs through internal, in situ processes of star formation.

The important take-away of this result is that it shows that the present theory of galaxy formation, where smaller spiral galaxies merge to form larger elliptical galaxies, does not fit the data. And if a theory does not fit the data, it must be abandoned.

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