Tag: astronomy

A solar system of exoEarths!

1:53 pm

Astronomers have discovered a nearby solar system of exoplanets, all approximately Earth-sized with at least three in the habitable.

Following these initial findings, the star was systematically monitored to find out whether it contained any other planets. The result of this follow-up exceeded all expectations: TRAPPIST-1 has at least seven planets, all of which are Earth-sized (to within 15%). The six nearest planets (b to g) orbit their star in 1.5 to 12 days (the period of the seventh planet remains to be determined), and are 20 to 90 times closer to their star than the distance from the Earth to the Sun. At such distances, the tidal forces exerted by the star are considerable, locking the planets into synchronous rotation, which means that they rotate about their axis exactly once in one orbit, thus always showing the same face to their star (just as the Moon does relative to the Earth).

The planets of TRAPPIST-1 have insolations, and therefore average temperatures, similar to Earth’s: the insolation of the innermost planet (b) is slightly higher than that of Mercury, while the outermost planets (g and h) have an insolation that is a little lower than that of Mars. The insolations of at least three of the planets (e, f and g) are compatible with the existence of liquid water on their surface for a wide range of atmospheric compositions, as is shown by numerical simulations of their climate. Due to their synchronous rotation, it cannot be excluded that the planets with the highest irradiation (b, c and d) may harbor liquid water in temperate regions with little or no sunlight.

More here. The star, a cool dwarf, is only 40 light years away.

Posted in the Belize City airport, as we wait for our pickup.

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UC-Berkeley and Google looking for amateur images of upcoming August eclipse

9:48 am

In the hope of producing a long movie of the August eclipse that will cross the entire continental United States, the University of California-Berkeley and Google have teamed up to put together a project that will gather images taken by amateurs.

The Eclipse Megamovie Project is seeking more than a thousand amateur astronomers and avid photographers to record the Aug. 21 total solar eclipse and upload their photos to be stitched together into a movie documenting the path of totality from landfall in Oregon until the moon’s shadow slips over the Atlantic Ocean off South Carolina.

While no one on the ground will see the total eclipse for more than 2 minutes and 40 seconds, depending on how close they are to the center of the path of totality, the images collected by the Megamovie’s volunteer team will be turned into a 90-minute eclipse movie unlike anything seen before. Even an airplane flying along the path of totality can only capture at most a four- to five-minute movie, since the moon’s shadow moves along the ground at up to 1,500 miles per hour. The last time anyone tried to stitch together eclipse images like this may have been in the 1800s via hand-drawn sketches, without the benefit of today’s modern digital technology.

While I think this is a great idea, I must state my reservations about UC-Berkeley. This university is hostile to free speech, and actually encourages violence against conservatives who either attend the university or come to speak there. To work with it on this project would be a kind of endorsement of that behavior.

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A comet breaks apart

9:27 am

On February 12 members of the amateur astronomy organization Slooh actually viewed the break-up of Comet 73P/Schwassmann-Wachmann into two large fragments.

On the night of February 12th, Slooh members using the company’s telescopes in Chile were able to view the comet as it broke into two pieces. This seems to be the continuation of a process that was first witnessed in 1995, then again in 2006.

Slooh members were among the first to confirm that the nucleus of comet 73P/Schwassmann-Wachmann had split into at least two large pieces. “They immediately pointed Slooh’s telescopes to capture the event,” says Slooh Astronomer, Paul Cox. “Members will continue to monitor the comet live over the coming weeks – assuming the comet survives that long.”

They have created an animation from their images, but it appears that they only started taking images after the actual breakup, so the animation shows the two fragments, but not the moment they broke apart.

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Plotting the interstellar path to Proxima Centauri

8:40 am

Scientists have calculated the slingshot route that Breakthrough Starshot’s tiny interstellar spacecraft should take in order to reach Proxima Centauri while also gathering the maximum scientific data while zipping past the binary stars of Alpha Centauri.

The solution is for the probe’s sail to be redeployed upon arrival so that the spacecraft would be optimally decelerated by the incoming radiation from the stars in the Alpha Centauri system. René Heller, an astrophysicist working on preparations for the upcoming Exoplanet mission PLATO, found a congenial spirit in IT specialist Michael Hippke, who set up the computer simulations. The two scientists based their calculations on a space probe weighing less than 100 grams in total, which is mounted to a 100,000-square-metre sail, equivalent to the area of 14 soccer fields. During the approach to Alpha Centauri, the braking force would increase. The stronger the braking force, the more effectively the spacecraft’s speed can be reduced upon arrival. Vice versa, the same physics could be used to accelerate the sail at departure from the solar system, using the sun as a photon cannon.

The tiny spacecraft would first need to approach the star Alpha Centauri A as close as around four million kilometres, corresponding to five stellar radii, at a maximum speed of 13,800 kilometres per second (4.6 per cent of the speed of light). At even higher speeds, the probe would simply overshoot the star.

While most of this is hardly revolutionary, this is still the first time anyone has done the hard math based upon a real mission concept.

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New measurements of the universe’s expansion rate

3:41 pm

The uncertainty of science: New measurements of the universe’s expansion rate are apparently in agreement with some previous measurements but not with others.

The Hubble constant — the rate at which the Universe is expanding — is one of the fundamental quantities describing our Universe. A group of astronomers, the H0LiCOW collaboration, used the NASA/ESA Hubble Space Telescope and other telescopes in space and on the ground to observe five galaxies in order to arrive at an independent measurement of the Hubble constant. The new measurement is completely independent of — but in excellent agreement with — other measurements of the Hubble constant in the local Universe that used Cepheid variable stars and supernovae as points of reference.

…However, the value measured by Suyu and her team, as well as those measured using Cepheids and supernovae, are different from the measurement made by the ESA Planck satellite. But there is an important distinction — Planck measured the Hubble constant for the early Universe by observing the cosmic microwave background. While the value for the Hubble constant determined by Planck fits with our current understanding of the cosmos, the values obtained by the different groups of astronomers for the local Universe are in disagreement with our accepted theoretical model of the Universe.

Both measurements are very precise, but they do not match, suggesting that there are some basic fundamentals here that astronomers simply do not yet understand.

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ELT construction moves forward

9:06 am

The European Southern Observatory (ESO) today signed contracts for the construction of the mirrors and sensor for its Extremely Large Telescope (ELT).

At a ceremony today at ESO’s Headquarters four contracts were signed for major components of the Extremely Large Telescope (ELT) that ESO is building. These were for: the casting of the telescope’s giant secondary and tertiary mirrors, awarded to SCHOTT; the supply of mirror cells to support these two mirrors, awarded to the SENER Group; and the supply of the edge sensors that form a vital part of the ELT’s huge segmented primary mirror control system, awarded to the FAMES consortium. The secondary mirror will be largest ever employed on a telescope and the largest convex mirror ever produced.

The construction of the 39-metre ELT, the largest optical/near-infrared telescope in the world, is moving forward. The giant telescope employs a complex five-mirror optical system that has never been used before and requires optical and mechanical elements that stretch modern technology to its limits.

Meanwhile it remains unclear when and where the Thirty Meter Telescope (TMT) will be built.

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Private money to VLT to search for Earthlike planets at Alpha Centauri

9:42 am

The privately funded Breakthrough Initiatives project has committed funds to upgrade the Very Large Telescope in Chile in exchange for telescope time to look for Earthlike planets in orbit around Alpha Centauri.

Facebook’s Mark Zuckerberg, Russian entrepreneur Yuri Milner and physicist Stephen Hawking are hoping to find Earth-like planets in our neighbouring star system, Alpha Centauri. Together they will upgrade the Very Large Telescope (VLT) to look for potentially habitable worlds as part of the ‘Breakthrough’ initiatives.

These planets could be the targets for a launch of tiny space probes to track down aliens within our lifetimes, the European Southern Observatory (ESO) said.

This is exactly how astronomy used to function. Rather than get money from the government in exchange for doing the research it wanted done, astronomers obtained funds from wealthy individuals or businesses to build and upgrade their telescopes in exchange for doing the research that interested these funding sources. The difference? The work was privately funded voluntarily, rather than coerced from the public through taxes.

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The status of telescopes the NSF is getting rid of

9:08 am

Back in 2012 the National Science Foundation (NSF) proposed that it cease funding a slew of older, smaller telescopes in order to use that money to fund the construction and operation of newer more advanced facilities. This article, focused on the fate of the Arecibo Observatory in Puerto Rico, provides a nice table that shows the status of these telescopes.

The options were either to find new funding, be mothballed, or even demolished. It appears that most of the telescopes in question have found new funding and will remain in use in some manner. The one telescope that has apparently failed to obtain any additional funding from others is the McMath–Pierce Solar Telescope on Kitt Peak in Arizona, which when built in 1962 was the world’s largest solar telescope, an honor for which it is still tied.

In 2015 I had written an article for Sky & Telescope about how these budget cuts were effecting the telescopes on Kitt Peak. At that time the people in charge of McMath-Pierce were hunting for new support but were coming up short. Almost two years later it appears that their hunt has been a failure, and the telescope will likely be shut down, and possibly demolished.

It will be a sad thing if McMath-Pierce is lost, but I am not arguing to save it. If its observational capabilities were truly valuable and needed by the scientific community than someone would have come forward to finance it. That no one has suggests that the money really can be spent more usefully in other ways.

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Could Tabby’s Star have eaten a planet?

8:50 am

A new theory has been proposed by astronomers to explain the unprecedented dimming of Tabby’s Star, and it isn’t an alien civilization.

If Tabby’s star devoured a planet in the past, the planet’s energy would have made the star temporarily brighten, then gradually dim to its original state. The bigger the planet was, the longer the star would take to dim. Depending on the size of the planet, this event could have happened anywhere between 200 and 10,000 years ago.

As the planet fell into its star, it could have been ripped apart or had its moons stripped away, leaving clouds of debris orbiting the star in eccentric orbits. Every time the debris passes between us and the star, it would block some light, making the star seem to blink.

If true, this theory would suggest that such events can happen more than scientists has expected. Moreover, this theory can be tested during future observations when the star experiences its next dimming.

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Hubble takes a look at both Voyagers’ interstellar path

10:43 am

Using the Hubble Space Telescope astronomers have taken a peek at the interstellar material that the two Voyager spacecraft will travel through as they move out and leave the solar system in the coming decades.

Voyager 1 is 13 billion miles from Earth, making it the farthest human-made object ever built. In about 40,000 years, after the spacecraft will no longer be operational and will not be able to gather new data, it will pass within 1.6 light-years of the star Gliese 445, in the constellation Camelopardalis. Its twin, Voyager 2, is 10.5 billion miles from Earth, and will pass 1.7 light-years from the star Ross 248 in about 40,000 years.

For the next 10 years, the Voyagers will be making measurements of interstellar material, magnetic fields, and cosmic rays along their trajectories. Hubble complements the Voyagers’ observations by gazing at two sight lines along each spacecraft’s path to map interstellar structure along their star-bound routes. Each sight line stretches several light-years to nearby stars. Sampling the light from those stars, Hubble’s Space Telescope Imaging Spectrograph measured how interstellar material absorbed some of the starlight, leaving telltale spectral fingerprints.

Hubble found that Voyager 2 will move out of the interstellar cloud that surrounds the solar system in a couple thousand years. The astronomers, based on Hubble data, predict that the spacecraft will spend 90,000 years in a second cloud before passing into a third interstellar cloud.

This is very clever science. It allows data from Hubble to complement the data from the two Voyager spacecraft to better understand the interstellar regions that surround our solar system.

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Astronomers predict binary stellar merger in 2022

9:37 am

Astronomers are predicting that a two binary stars that orbit so close together that they share an atmosphere will merge and explode as a bright red nova in approximately five years.

According to the actual paper [pdf], they also predict that this will be a naked eye event, visible in the northern hemisphere.

Note that a red nova is not a supernova. These are different types of explosions, with the supernova many times more powerful and rare. Nonetheless, the event itself will spectacular, should the prediction be correct.

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Astronomers identify for the first time the source of a fast radio burst

7:25 pm

For the first time astronomers have pinned down the location of a fast radio burst (FRBs), short bursts lasting only seconds that were only discovered about a decade ago.

A dim dwarf galaxy 2.5 billion light years from Earth is sending out the mysterious millisecond-long blasts of radio waves, researchers report Wednesday in Nature and Astrophysical Journal Letters. The bursts traverse vast expanses of time and intergalactic space before reaching our planet. “This really is the first ironclad association of a fast radio burst with another astronomical source, so it’s a pretty huge result,” said Duncan Lorimer, an astronomer at West Virginia University who reported the first detection of a fast radio burst (FRB) in 2007.

The uncertainty of science: Only 18 FRBs have been identified since they were first discovered. Until now, it was unclear whether they occurred in our galaxy or beyond, though it was suspected they were coming from other galaxies. This discovery proves that. What remains unknown is what causes the burst, which signals an energy pulse equivalent to that of 500 million suns.

“I am not exaggerating when I say there are more models for what FRBs could be than there are FRBs,” said Cornell astronomer Shami Chatterjee, the lead author of the new Nature paper. Many scientists think the bursts are emitted by distant neutron stars, the super-dense embers of exploded suns. But some believe they must originate in our own galaxy. Still more suggest that FRBs could be caused by cataclysms like a supernova or a collision of two stars. This last theory was compelling because most FRB detections were one-off events — astronomers never spotted more than one flare from a single source.

Today’s announcement was made possible by the fact that the burst itself is repeating. In fact, it is the only FRB so far known to do so, which also means that what they learn about it might not be applicable to the other bursts.

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Vera Rubin R.I.P.

9:17 pm

Vera Rubin, whose work helped confirm the existence of dark matter, passed away December 25 at the age of 88.

In the 1960s, Rubin’s interest in how stars orbit their galactic centers led her and colleague Kent Ford to study the Andromeda galaxy, M31, a nearby spiral. The two scientists wanted to determine the distribution of mass in M31 by looking at the orbital speeds of stars and gas at varying distances from the galactic center. They expected the speeds to conform to Newtonian gravitational theory, whereby an object farther from its central mass orbits slower than those closer in. To their surprise, the scientists found that stars far from the center traveled as fast as those near the center.

After observing dozens more galaxies by the 1970s, Rubin and colleagues found that something other than the visible mass was responsible for the stars’ motions. Each spiral galaxy is embedded in a “halo” of dark matter—material that does not emit light and extends beyond the optical galaxy. They found it contains 5 to 10 times as much mass as the luminous galaxy. As a result of Rubin’s groundbreaking work, it has become apparent that more than 90% of the universe is composed of this invisible material. The first inkling that dark matter existed came in 1933 when Swiss astrophysicist Fritz Zwicky of Caltech proposed it. But it was not until Rubin’s work that dark matter was confirmed.

Rubin was a top notch astronomer, which is why she was part of this important discovery. She was also an exception, as at the time relatively few women were interested in becoming astronomers. Be prepared, however, for a slew of articles in the next few days focused not about her work and her contributions to science, but focused instead almost entirely on the sexist oppression she had to overcome in the evil sexist male chauvinist society of mid-twentieth-century America.

All those articles will be wrong. While there were certainly obstacles in Rubin’s way because of her sex, they were hardly as bad as it will be made out to be. Worse, this focus on gender and oppression will distract from honoring the passing of a great astronomer. It will also distract from the significance of her discovery, which continues to baffle astronomers a half century later.

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NASA estimates one month to address Webb vibration issues

9:27 am

NASA now expects it will take a month to assess and fix the issues uncovered during vibration testing of the James Webb Space Telescope.

Thomas Zurbuchen, the new head of NASA’s Science Mission Directorate (SMD), told SpacePolicyOnline.com that dealing with the problem likely will consume one of the remaining six months of schedule reserve.

No one at NASA has as yet explained exactly what the “anomalous readings” were during vibration testing. Nor did Zurbuchen indicate what the fix would be.

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Computer modeling suggests light fluctuations at Tabby’s Star are natural

10:16 am

A computer analysis of the light fluctuations of Tabby’s Star suggest to astronomers that the changes are not caused by objects blocking the star (such as an alien Dyson Sphere under construction) but are instead natural variations caused as the star evolves.

This conclusion is decidedly uncertain. They do not know the nature of this stellar evolution. And they are applying avalanche models to the star to come to this conclusion.

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Betelgeuse might have eaten a star

10:31 am

Because the red giant star Betelgeuse rotates far faster than it should, astronomers are now theorizing that when it expanded into its present red giant phase about 100,000 years ago it swallowed a companion star which contributed its own angular momentum to the system to speed up the rotation.

This theory is bolstered by evidence of a shell of matter surrounding Betelgeuse that is possibly a remnant of that destroyed star.

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Did a giant black hole eat a star?

10:45 am

New data now suggests that what astronomers had thought was the brightest supernova ever detect might have instead been the ripping apart of a star as it passed too close to a supermassive black hole.

In this scenario, the extreme gravitational forces of a supermassive black hole, located in the centre of the host galaxy, ripped apart a Sun-like star that wandered too close — a so-called tidal disruption event, something so far only observed about 10 times. In the process, the star was “spaghettified” and shocks in the colliding debris as well as heat generated in accretion led to a burst of light. This gave the event the appearance of a very bright supernova explosion, even though the star would not have become a supernova on its own as it did not have enough mass. The team based their new conclusions on observations from a selection of telescopes, both on the ground and in space. Among them was the NASA/ESA Hubble Space Telescope, the Very Large Telescope at ESO’s Paranal Observatory and the New Technology Telescope at ESO’s La Silla Observatory

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Scientists puzzle over possible connection between a fast radio burst and a gamma ray burst

9:31 am

The uncertainty of science: In trying to explain the relatively new mystery of fast radio bursts (FRB), of which only about 20 have been detected and of which very little is known, scientists are intrigued by a gamma ray burst (GRB) that apparently occurred at the same time and place of one FRB.

Seeing the FRB event in a different wavelength would normally help astronomers better understand the FRB The problem is that this particular GRB only makes the mystery of FRBs more baffling.

One puzzle is that the two signals portray different pictures of the underlying source, which seems to be as much as 10 billion light years (3.2 gigaparsecs) away. Whereas the radio burst lasted just a few milliseconds, the γ-ray signal lasted between two and six minutes, and it released much more energy in total than the radio burst. “We’ve pumped up the energy budget more than a billion times,” says study co-author Derek Fox, an astrophysicist at Penn State.

This has big implications for the FRB’s origin. One leading theory suggests that FRBs are flares from distant magnetars — neutron stars with enormous magnetic fields that could generate short, energetic blasts of energy, and do so repeatedly, as at least one FRB is known to do. Although magnetars are thought to produce γ-rays, they would not emit such high energy and over such a long time, says Fox. “This is a severe challenge for magnetar models,” he says.

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TMT legal case in Hawaii gets messier

7:02 pm

The permit process in Hawaii for the Thirty Meter Telescope has gotten far messier, with the telescope’s opponents appealing to the state’s Supreme Court, complaining about witness procedures and the lawyers who are working for the state, while the land board running the procedures has asked the court to dismiss this appeal.

Essentially, the opponents are using every trick in the book to delay the permit process, and it appears that the law in Hawaii, including one just passed in August, is designed to aid them in this tactic.

TMT will not be built in Hawaii.The consortium that is building it needs a decision by early next year at the latest. They ain’t gonna get it. The luddites going to win, and Hawaii will be far poorer because of it.

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Largest Texas meteorite ever found by accident on dude ranch

10:13 am

The largest Texas meteorite ever, weighing 760 pounds, has been found on a Texas dude ranch.

The owner found it entirely by accident. It apparently had been there for a long time, but no one had noticed it, mostly because of its weathered appearance that made it appear much like any other boulder. Tests proved beyond doubt, however, that it was a meteorite, an L4 chrondite. It has now been sold to a meteorite collection at Texas Christian University in Ft. Worth.

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Moon found orbiting one of the larger known Kuiper belt object

6:22 pm

Astronomers have found a moon circling 2007 Or10, one of the Kuiper Belts eight largest objects and the only one as yet unnamed.

Astronomers Gábor Marton and Csaba Kiss (Konkoly Observatory, Hungary), and Thomas Müller (Max Planck Institute, Germany) have identified a moon orbiting 2007 OR10. They spotted it in Hubble Space Telescope images taken in September 2010 as part of a survey of trans-Neptunian objects. Marton announced the discovery this week at a joint meeting of the AAS’s Division for Planetary Sciences and the European Planetay Science Congress.

Although 2007 OR10 itself has been known for almost a decade, only recently have researchers realized that it’s surface is quite dark and therefore that it must be quite sizable, with an estimated diameter of 1,535 km (955 miles). This makes it the third-largest dwarf planet, after Pluto and Eris. It also ranks third for distance — 13 billion km or 87 astronomical units away — drifting among the stars of central Aquarius at a dim magnitude 21.

Of the eight largest Kuiper Belt objects, only Sedna has not yet been found to have a moon.

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Expansion rate of the universe might not be accelerating

6:06 pm

The uncertainty of science: A new review of the data suggests that the expansion of the universe might not be accelerating as posited based on research done in the 1990s.

Making use of a vastly increased data set – a catalogue of 740 Type Ia supernovae, more than ten times the original sample size – the researchers have found that the evidence for acceleration may be flimsier than previously thought, with the data being consistent with a constant rate of expansion.

The study is published in the Nature journal Scientific Reports.

Professor Sarkar, who also holds a position at the Niels Bohr Institute in Copenhagen, said: ‘The discovery of the accelerating expansion of the universe won the Nobel Prize, the Gruber Cosmology Prize, and the Breakthrough Prize in Fundamental Physics. It led to the widespread acceptance of the idea that the universe is dominated by “dark energy” that behaves like a cosmological constant – this is now the “standard model” of cosmology.

‘However, there now exists a much bigger database of supernovae on which to perform rigorous and detailed statistical analyses. We analysed the latest catalogue of 740 Type Ia supernovae – over ten times bigger than the original samples on which the discovery claim was based – and found that the evidence for accelerated expansion is, at most, what physicists call “3 sigma”. This is far short of the 5 sigma standard required to claim a discovery of fundamental significance.

I am not surprised. In fact, I remain continually skeptical about almost all cosmological theories. They might be the best we have, based on the facts available, but they are also based upon incredibly flimsy facts.

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TMT hearing a fiasco

8:00 pm

The initial hearing in Hawaii for the second permit application of the Thirty Meter Telescope today appears to have been a complete fiasco, designed to extend the proceedings as long as possible, ad infinitum.

Confusion reigned as Thursday’s hearing got underway in a Hilo hotel banquet room. Various telescope opponents complained about the scheduling and location of the hearing. One lawyer wanted to know the process for making objections. More than an hour went by before the first witness, environmental planner Perry White, was called to testify.

All witnesses will be allowed to provide a 10-minute summary of written testimony already submitted. But before White could provide his summary, there were various objections about qualifying him as an expert. Nearly two dozen people— many who are individual telescope opponents who don’t have lawyers representing them — will have a chance to cross-examine each witness.

Cross-examination of White will resume Monday.

It is very clear to me that Hawaii is stalling, designing the hearings so that they will last forever. TMT will never get built in Hawaii. It is time to say bye-bye and go somewhere where knowledge and technology is treasured.

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The clouds of hot Jupiter exoplanets

11:24 am

Exoplanet clouds

Cool image time! The image on the right, reduced to show here, provides an overall summary of what astronomers know about the atmospheres of many gas giant exoplanets that also orbit very close to their suns and are tidally locked. The view is of the planet hemisphere facing away from the star, which is also where most of the clouds are thought to be. These results come from Kepler data combined with computer modeling, and show what scientists thinks happens with different cloud compositions at different temperatures.

Link fixed!

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New object found beyond Kuiper belt

10:20 am

Worlds without end: Astronomers have discovered another object far beyond Pluto and in an elliptical orbit whose farthest point is 1,450 astronautical units, or about 135 billion miles from the Sun.

This is not the same object recently discovered in a somewhat similar elliptical orbit.

Astronomers right now do not understand the formation process that put these objects in these distant orbits. Some think the objects might have originally come from the Oort cloud that is even farther out from the Sun, their orbits shifted by the as-yet undiscovered Planet X that astronomers love to talk about, but others are skeptical. Since no one has ever actually detected anything in the the theorized Oort Cloud, it is also possible that it does not exist as presently theorized, and might actually be a more scattered collection of objects, like these new discoveries, that travel both farther and closer to the Sun.

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Ten times more galaxies than previously believed

9:44 am

The uncertainty of science: A new analysis from Hubble and other telescope data suggests that the universe actually contains ten times more galaxies than previously estimated, several trillion instead of the past estimate of 100 to 200 billion.

I would not bet much money on this conclusion. I suspect that further research will find even more galaxies, since our deep observations of the universe are at the moment confined to a mere handful of Hubble deep field images that cover only a few tiny specks of space.

This new analysis however did confirm previous estimates that suggest the universe has evolved and changed significantly over time.

In analysing the data the team looked more than 13 billion years into the past. This showed them that galaxies are not evenly distributed throughout the Universe’s history. In fact, it appears that there were a factor of 10 more galaxies per unit volume when the Universe was only a few billion years old compared with today. Most of these galaxies were relatively small and faint, with masses similar to those of the satellite galaxies surrounding the Milky Way.

These results are powerful evidence that a significant evolution has taken place throughout the Universe’s history, an evolution during which galaxies merged together, dramatically reducing their total number. “This gives us a verification of the so-called top-down formation of structure in the Universe,” explains Conselice.

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A large Kuiper Belt object discovered

3:55 pm

Astronomers have detected a new but very distant Kuiper Belt object.

For now, his team knows little more about their distant discovery other than its orbit and apparent brightness. Given its distance, however, the object should be sizable — anywhere from 400 km across (if its surface is bright and 50% reflective) to 1,200 km (if very dark and 5% reflective). If its true size edges toward the larger end of this range, then 2014 UZ224 would likely qualify for dwarf-planet status.

Fortunately, we should have a much better estimate of the object’s size very soon. Gerdes has used the ALMA radio-telescope array to measure the heat radiating from 2014 UZ224, which can be combined with the optical measurements to yield its size and albedo.

The object has a very eccentric 1,140 year orbit, coming as close to the sun as Pluto at its closest and almost five times farther away at its furthest.

Note: I have changed the article title because this new object is almost certainly not bigger the Pluto, as one of my readers pointed out.

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