Tag: astronomy

TMT construction begins July 15

8:43 pm

According to a press announcement today from the governor’s office in Hawaii, construction of the Thirty Meter Telescope will finally begin during the week of July 15 following several years of delays due to protests.

The State Department of Transportation announced that Mauna Kea Access Road will be closed and there could be lane and other road closures associated with large equipment movement beginning July 15. In addition, hunting units A, K, and G in the Mauna Kea Forest Reserve area will be temporarily closed to hunting effective July 15. Both measures are being taken to ensure the safety and security of the public and personnel involved in moving equipment for the TMT project up the Mauna Kea Access Road.

Expect more protests. The real question is whether the Democratic governor David Ige can stand up to them, especially because these protesters have been using the kind of identity politics that the Democratic Party relies on. Ige would have to defy that, and I haven’t seen a Democrat do that in decades.

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Astronomers find kilometer-sized asteroid with shortest year

10:10 am

Astronomers have found a kilometer-sized asteroid with a year only 151 days long, the shortest year of any asteroid.

The asteroid has been dubbed 2019 LF6.

In its orbit, the asteroid swings out beyond Venus and, at times, comes closer in than Mercury, which circles the sun every 88 days. 2019 LF6 is one of only 20 known “Atira” asteroids, which are objects whose orbits fall entirely within Earth’s.

Atira asteroids are difficult to find because they are so close to the Sun, which makes observations difficult if not impossible. Expect more such discoveries as the technology to make these observations improves.

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Astronomers map exoplanet atmosphere of super-Earth

9:26 am

Worlds without end: Using both the Hubble and Spitzer space telescopes, astronomers have characterized the atmosphere of an exoplanet with a mass between that of the Earth and Neptune.

Astronomers enlisted the combined multi-wavelength capabilities NASA’s Hubble snd Spitzer space telescopes to do a first-of-a-kind study of GJ 3470 b’s atmosphere. This was accomplished by measuring the absorption of starlight as the planet passed in front of its star (transit) and the loss of reflected light from the planet as it passed behind the star (eclipse). All totaled, the space telescopes observed 12 transits and 20 eclipses. The science of analyzing chemical fingerprints based on light is called “spectroscopy.”

“For the first time we have a spectroscopic signature of such a world,” said Benneke. But he is at a loss for classification: Should it be called a “super-Earth” or “sub-Neptune?” Or perhaps something else?

Fortuitously, the atmosphere of GJ 3470 b turned out to be mostly clear, with only thin hazes, enabling the scientists to probe deep into the atmosphere. “We expected an atmosphere strongly enriched in heavier elements like oxygen and carbon which are forming abundant water vapor and methane gas, similar to what we see on Neptune”, said Benneke. “Instead, we found an atmosphere that is so poor in heavy elements that its composition resembles the hydrogen/helium rich composition of the Sun.”

To me, our knowledge of exoplanets today is beginning to resemble our knowledge of the planets in the solar system c. 1950. The little data we have gives us a vague idea of what’s there, but there are so many gaps and uncertainties that no one should be confident about drawing any firm conclusions.

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New image of Eta Carina from Hubble

7:27 pm

Eta Carina
Click for full image.

Using the Hubble Space Telescope, astronomers have taken a new spectacular image of the Luminous Blue Giant star Eta Carina. The image on the right is that photograph, reduced to post here.

Using Hubble’s Wide Field Camera 3 to map the ultraviolet-light glow of magnesium embedded in warm gas (shown in blue), astronomers were surprised to discover the gas in places they had not seen it before.

Scientists have long known that the outer material thrown off in the 1840s eruption has been heated by shock waves after crashing into the doomed star’s previously ejected material. In the new images, the team had expected to find light from magnesium coming from the same complicated array of filaments as seen in the glowing nitrogen (shown in red). Instead, a completely new luminous magnesium structure was found in the space between the dusty bipolar bubbles and the outer shock-heated nitrogen-rich filaments.

Eta Carina had a major eruption in the 1840s, followed by other lesser outbursts, the evidence of which is obvious in this and other earlier Hubble images. In fact, over the past twenty-five years Hubble has actually tracked the expansion of those two lobes of material being flung from the star hidden deep in the material.

Someday in the far future astronomers believe it will die as a supernova, though that is only a hypothesis at this point, based on our presently limited understanding of stellar evolution.

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TESS finds exoplanet smaller than Earth

10:08 pm

Worlds without end: TESS has now found an exoplanet somewhere between Mars and the Earth in size, and is part of a solar system with two other Earth-sized planets.

L 98-59b is around 80% Earth’s size and about 10% smaller than the previous record holder discovered by TESS. Its host star, L 98-59, is an M dwarf about one-third the mass of the Sun and lies about 35 light-years away in the southern constellation Volans. While L 98-59b is a record for TESS, even smaller planets have been discovered in data collected by NASA’s Kepler satellite, including Kepler-37b, which is only 20% larger than the Moon.

The two other worlds in the system, L 98-59c and L 98-59d, are respectively around 1.4 and 1.6 times Earth’s size. All three were discovered by TESS using transits, periodic dips in the star’s brightness caused when each planet passes in front of it.

None of these planets is considered in the habitable zone however. Instead, they experience solar energies comparable to Venus.

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Fast radio burst located for the first time

1:30 pm

Astronomers have for the first time pinpointed the location of a non-repeating fast radio burst.

In a historic first, an international team of researchers have discovered the source of a non-repeating fast radio burst and traced its origin to a galaxy 4 billion light-years away.

The monumental findings, published in AAAS journal Science on Thursday, detail the discovery and localization of FRB 180924, a powerful, one-off fast radio burst that lasted for just a fraction of a second. Speculation about the cause of the bizarre signals takes in everything from explosive neutron stars to alien spacecraft, and while we’re still not sure what’s causing them, the revelation puts astronomers one step closer to their true nature.

“This is the big breakthrough that the field has been waiting for since astronomers discovered fast radio bursts in 2007,” said Keith Bannister, lead author of the paper and principal research engineer with Australia’s Commonwealth Scientific and Industrial Research Organisation.

Knowing the distance for the burst makes it possible to calculate how powerful it was, which helps theorists come up with an explanation for what might have caused it. Similarly, knowing its location–on the outskirts of a spiral galaxy like the Milky Way–helps them further constrain those theories.

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The Whirlpool Galaxy across many wavelengths

11:42 pm

The Whirlpool Galaxy
Click for full image.

Cool image time! The sequence of images above, reduced to post here, were taken in multiple wavelengths by the 2.1 meter Kitt Peak National Observatory in Arizona and the Spitzer Space Telescope in orbit.

The Whirlpool galaxy, also known as Messier 51 and NGC 5194/5195, is actually a pair of galaxies that are tugging and distorting each other through their mutual gravitational attraction. Located approximately 23 million light-years away, it resides in the constellation Canes Venatici.

The leftmost panel shows the Whirlpool in visible light, much as our eye might see it through a powerful telescope. In fact, this image comes from the Kitt Peak National Observatory 2.1-meter (6.8-foot) telescope. The spiraling arms are laced with dark threads of dust that radiate little visible light and obscure stars positioned within or behind them.

The second panel from the left includes two visible-light wavelengths (in blue and green) from Kitt Peak but adds Spitzer’s infrared data in red. This emphasizes how the dark dust veins that block our view in visible light begin to light up at these longer, infrared wavelengths.

Spitzer’s full infrared view can be seen in the right two panels, which cover slightly different ranges of infrared light.

The infrared views of the Whirlpool galaxy also show how dramatically different its two component parts are: The smaller companion galaxy at the top of the image has been stripped nearly clean of dust features that stand out so brilliantly in the lower spiral galaxy. The faint bluish haze seen around the upper galaxy is likely the blended light from stars thrown out of the galaxies as these two objects pull at each other during their close approach.

The Spitzer images above are likely among the last we shall see from that telescope, which has been in orbit since 2003 with a planned mission of only 2.5 years. As its cryogenic coolant became depleted in 2009, it has been functioning in a somewhat limited phase since. NASA will officially end the mission on January 30, 2020, more than thirteen years beyond that initial lifespan.

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Battery screw-up delays Russian X-Ray telescope launch

8:39 am

The Russians this morning postponed today’s launch of the Spectr-RG X-Ray space telescope until July when it was discovered that one of the payload’s batteries had been drained prematurely.

[T]he Moskovsky Komsomolets tabloid reported from Baikonur that the problem had been discovered at least a day earlier, but the entire project team at the launch site was kept in the dark until the launch date, not to interfere with Vladimir Putin’s annual press-conference.

According to the paper, the battery was accidentally activated on the launch pad instead of the planned moment after the separation of the spacecraft from the Block DM-03 upper stage. The error was blamed on the erroneous wiring setup by RKK Energia specialists (Block DM-03 prime contractor) between the upper stage and the spacecraft, which caused a complete drainage of the battery designed to be re-charged from solar panels. After the return of the rocket to the vehicle assembly building, the battery would have to be re-charged and the power-supply system re-wired, Moskovsky Komsomolets said. [emphasis mine]

If this report is true, it appears that the Russian government has done nothing to fix the quality control programs in its aerospace industry, and in fact is helping to contribute to them by playing games with launch procedures for the sake of its own public relations.

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Hawaii fully okays construction of TMT, removes protest structures

11:14 pm

The Hawaiian state government today finally gave the go-ahead for the construction of the Thirty Meter Telescope (TMT), sending close to 100 police officers to the mountain to remove four structures built by protesters to block construction.

[Democratic government David] Ige said he believes the state now has sufficient legal basis for construction to go more smoothly than it did following the telescope’s 2014 groundbreaking. After significant protests in 2014 and 2015, the state Supreme Court ruled in 2015 that a 2011 permit from the state Board of Land and Natural Resources was invalid after finding the Land Board violated due process rights of project opponents by voting before the first contested case was held.

However, the Supreme Court approved an amended permit late last year, allowing the project to seek a notice to proceed. The conditions of the amended permit state that the TMT will be the last telescope to be built on Maunakea and that five other telescopes at the summit will be decommissioned and removed.

Despite Ige’s confidence in the process, opponents are preparing for further protests. Kanuha said he intends to “try and stop it the same way we did the first time.”

“This is about more than the mountain, this is about how we treat land and natural resources in Hawaii,” Kanuha said. “If we allow this to happen, we can kiss goodbye all we hold precious in Hawaii. It’s just a matter of time.”

Another protester, Lakea Trask, warned of an inevitable conflict. “The state is declaring war on Hawaiians,” said Trask, who was arrested and charged with trespassing during the 2015 protests. “The state is now using TMT to declare war, an all-out war on Hawaiians.”

First, this is the second time the state has approved this project, which followed the law both the first time and now. Second, the protests that stopped construction in 2014 and 2015 were not “significant” but were led by a very small number of people. Third, those same protesters, as quoted above, probably intend to repeat their actions once construction resumes this summer. If so, expect violence. These people know they will not be seriously punished for breaking the law, and will take advantage of this.

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The make-up and temperature of Uranus’s rings

10:34 am

The rings of Uranus

New radio images taken by the ground-based telescopes by the ALMA and VLT telescopes in Chile have allowed scientists to better determine the make-up and temperature of the rings of Uranus.

The image above is from their paper. From the caption:

Images of the Uranian ring system at 3.1 mm (ALMA Band 3; 97.5 GHz), 2.1 mm (ALMA Band 4; 144 GHz), 1.3 mm (ALMA Band 6; 233 GHz), and 18.7 μm (VLT VISIR; 100 THz)…The planet itself is masked since it is very bright compared to the rings.

From the article above:

The new images taken by the Atacama Large Millimeter/submillimeter Array (ALMA) and the Very Large Telescope (VLT) allowed the team for the first time to measure the temperature of the rings: a cool 77 Kelvin, or 77 degrees above absolute zero — the boiling temperature of liquid nitrogen and equivalent to 320 degrees below zero Fahrenheit.

The observations also confirm that Uranus’s brightest and densest ring, called the epsilon ring, differs from the other known ring systems within our solar system, in particular the spectacularly beautiful rings of Saturn.

“Saturn’s mainly icy rings are broad, bright and have a range of particle sizes, from micron-sized dust in the innermost D ring, to tens of meters in size in the main rings,” said Imke de Pater, a UC Berkeley professor of astronomy. “The small end is missing in the main rings of Uranus; the brightest ring, epsilon, is composed of golf ball-sized and larger rocks.” [emphasis mine]

The mystery is why this ring has no dust, something not seen with any other ring system in the solar system, including the inner rings of Uranus itself..

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Two Earthlike planets possibly found around neaby red dwarf star

3:51 pm

The uncertainty of science: Astronomers think they may have detected evidence of two Earth-sized planets orbiting a tiny red dwarf star only twelve light years away.

Ribas and his colleagues are currently searching for planets orbiting 342 small stars, so they aimed the CARMENES instrument, located at Spain’s Calar Alto Observatory, at the mini-star.

CARMENES observed Teegarden’s star over three years, watching for the wiggles and tugs produced by any orbiting planets. In the end, more than 200 measurements suggested that two small worlds are jostling the star, each weighing in at approximately 1.1 times Earth’s mass. The team calculates that one of the planets, called Teegarden’s star b, completed an orbit in a mere 4.9 Earth-days; the other world, Teegarden’s star c, has an orbit of just 11.4 days.

There is great uncertainty in these results, as the article correctly notes. However, if confirmed these planets could be the home of a very ancient civilization, considering that the red dwarf star is already twice as old as our Sun. There also could be no life there at all, as red dwarf stars tend to be very lacking in many of the materials needed for life.

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New analysis throws wrench in formation theory of spirals in galaxies

8:29 am

The uncertainty of science: A new analysis of over 6000 galaxies suggests that a long-held model for the formation of spirals in galaxies is wrong.

[Edwin] Hubble’s model soon became the authoritative method of classifying spiral galaxies, and is still used widely in astronomy textbooks to this day. His key observation was that galaxies with larger bulges tended to have more tightly wound spiral arms, lending vital support to the ‘density wave’ model of spiral arm formation.

Now though, in contradiction to Hubble’s model, the new work finds no significant correlation between the sizes of the galaxy bulges and how tightly wound the spirals are. This suggests that most spirals are not static density waves after all.

Essentially, we still have no idea why spirals form in galaxies.

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Astronomers call for regulations to stop commercial satellite constellations

8:12 am

The astronomical community is now calling for new regulations to restrict the number of satellites that can be launched as part of the coming wave of new commercial constellations due to a fear these satellites will interfere with their observations.

Not surprising to me, it is the International Astronomical Union (IAU) that is taking the lead here.

The IAU statement urges satellite designers and policymakers to take a closer look at the potential impacts of satellite constellations on astronomy and how to mitigate them.

“We also urge appropriate agencies to devise a regulatory framework to mitigate or eliminate the detrimental impacts on scientific exploration as soon as practical,” the statement says. “We strongly recommend that all stakeholders in this new and largely unregulated frontier of space utilisation work collaboratively to their mutual advantage.”

When it comes to naming objects in space, the IAU likes to tell everyone else what to do. That top-down approach is now reflected in its demand that these commercial enterprises, with the potential to increase the wealth and knowledge of every human on Earth, be shut down.

The astronomy community has a solution, one that it has been avoiding since they launched Hubble in 1990, and that is to build more space-telescopes. Such telescopes would not only leap-frog the commercial constellations, it would routinely get them better results, far better than anything they get on Earth.

But no, they’d rather squelch the efforts of everyone else so they can maintain the status quo. They should be ashamed.

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VLT snaps image of double asteroid zipping past Earth

9:04 am

Double asteroid imaged by VLT

The Very Large Telescope (VLT) in Chile was successfully able to photograph the double asteroid that flew past the Earth on May 25 at a distance of 3.2 million miles and a speed of 43 thousand miles per hour.

The left image on the right is the raw image, while the right image is their reconstruction after applying adaptive-optics (AO) to the raw image. From the press release:

Bin Yang, VLT astronomer, declared “When we saw the satellite in the AO-corrected images, we were extremely thrilled. At that moment, we felt that all the pain, all the efforts were worth it.” Mathias Jones, another VLT astronomer involved in these observations, elaborated on the difficulties. “During the observations the atmospheric conditions were a bit unstable. In addition, the asteroid was relatively faint and moving very fast in the sky, making these observations particularly challenging, and causing the AO system to crash several times. It was great to see our hard work pay off despite the difficulties!”

To put it mildly, that right image is a fantasy. Astronomers love to tout the wonders of adaptive optics, but no matter how good it might be, it still is garbage-in-garbage-out, a computer simulation based on their guess at what the object would look like if there was no atmosphere in the way. In this particular case, they are being especially fantastic, and guaranteed to be wrong. It is impossible for them to extrapolate such minute surface details from the fuzzy image on the left.

Still, getting an image of this asteroid as it zipped by at that speed using such a large telescope is an achievement, and bodes well for the use of ground-based astronomy of near Earth asteroids.

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First movie of solar eclipse rediscovered

9:56 am

The first movie ever made of a solar eclipse, taken in 1900, has been rediscovered and restored.

The film was taken by British magician turned pioneering filmmaker Nevil Maskelyne on an expedition by the British Astronomical Association to North Carolina on 28 May, 1900. This was Maskelyne’s second attempt to capture a solar eclipse. In 1898 he travelled to India to photograph an eclipse where succeeded but the film can was stolen on his return journey home. It was not an easy feat to film. Maskelyne had to make a special telescopic adapter for his camera to capture the event. This is the only film by Maskelyne that we know to have survived.

I have embedded the movie below the fold.
» Read more

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Three exocomets found circling Beta Pictoris

7:31 am

The uncertainty of science: By analyzing data from the new space telescope TESS, astronomers think they have identified three exocomets orbiting the nearby star Beta Pictoris.

Why do I label this uncertain? Let the scientists themselves illustrate my doubt:

Sebastian Zieba, Master’s student in the team of Konstanze Zwintz at the Institute of Astro- and Particle Physics at the University of Innsbruck, discovered the signal of the exocomets when he investigated the TESS light curve of Beta Pictoris in March this year. “The data showed a significant decrease in the intensity of the light of the observed star. These variations due to darkening by an object in the star’s orbit can clearly be related to a comet,” Sebastian Zieba and Konstanze Zwintz explain the sensational discovery.

The press release provides no other information about why they think this darkening is because of comets rather than exoplanets or some other phenomenon. Based on this alone, I find this report very doubtful and highly speculative.

In related news, astronomers now claim they have detected eighteen more Earth-sized exoplanets in the data produced by Kepler, and they have done so by applying new algorithms to the data.

Large planets tend to produce deep and clear brightness variations of their host stars so that the subtle center-to-limb brightness variation on the star hardly plays a role in their discovery. Small planets, however, present scientists with immense challenges. Their effect on the stellar brightness is so small that it is extremely hard to distinguish from the natural brightness fluctuations of the star and from the noise that necessarily comes with any kind of observation. René Heller’s team has now been able to show that the sensitivity of the transit method can be significantly improved, if a more realistic light curve is assumed in the search algorithm. “Our new algorithm helps to draw a more realistic picture of the exoplanet population in space,” summarizes Michael Hippke of Sonneberg Observatory. “This method constitutes a significant step forward, especially in the search for Earth-like planets.”

This makes sense, but it must be understood that these are only candidate exoplanets, unconfirmed as yet. I would not be surprised if a majority are found to be false positives.

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More gravitational waves detected

9:47 am

Using the LIGO and Virgo gravitational wave telescopes astronomers have detected two more gravitational waves.

On April 25, 2019, one of the twin LIGO instruments and the Virgo detector observed a candidate signal which – if confirmed – would be the first binary neutron star merger during the third observation run, which began on April 1. A second candidate signal was seen on April 26, which – if confirmed – could be a never-observed-before collision of a neutron star with a black hole. The latter candidate was observed by both LIGO instruments and the Virgo detector. Dozens of telescopes on the Earth and in space are searching for electromagnetic or astro-particle counterparts. No identification with an electromagnetic transient signal nor a host galaxy has been made to date for either candidate.

The resolution of LIGO and VIRGO are somewhat limited, so other telescopes have to scan a very large part of the sky to spot a counterpart. It is therefore likely that it will be years before the first counterpart event is identified. When it is however it will tell us how far away the event was and confirm what kind of event it was. Right now, they are only making educated guesses.

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Lunar eclipse meteorite hit the Moon at almost 38,000 mph

10:33 am

By analyzing the data obtained of the meteorite impact that hit the Moon during the January 21 lunar eclipse, astronomers now estimate it crashed into the surface at almost 38,000 miles per hour and would have produced a crater about 50 feet across.

They also estimate that the meteorite itself had a mass of about 100 pounds with a diameter of between one to two feet.

The new crater itself has not yet been spotted, and probably can only be photographed with the high resolution camera on Lunar Reconnaissance Orbiter (LRO). I expect the LRO science team has already scheduled observations for this location. It will be interesting to see if the actual crater corresponds to the estimates of these astronomers.

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A stellar interloper in the Milky Way?

10:16 am

The uncertainty of science: Astronomers have identified a star inside the Milky Way whose chemical compositions suggests it was formed and originally came from a nearby dwarf galaxy.

This is the first discovery of a star having such extreme abundance ratios among Milky Way stars. On the other hand, several examples of stars having similar abundance ratios are known in dwarf galaxies. This result suggests that this star has formed in a dwarf galaxy, and has accreted onto the Milky Way in the process of galaxy formation. The abundance ratios of this star provide the clearest signature of merger events of dwarf galaxies in stellar chemical abundances known to date.

Though presently unique, this star probably is not the only such interloper in the Milky Way. It is believed by astronomers that our galaxy has absorbed a number of dwarf galaxies as it formed and grew, so we should expect more such stars to be discovered with time.

At the same time, we also must exercise some skepticism. Our understanding of galaxy formation is very preliminary, and thus the astronomers might be assuming too much about the chemical composition of dwarf galaxies in coming to this conclusion.

Posted at Los Angeles Airport on my way to Cannon Beach, Oregon, for a short vacation with friends.

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New Hubble data baffles cosmologists about universe’s expansion rate

10:15 am

The uncertainty of science: New and very firm data from the Hubble Space Telescope on the universe’s expansion rate conflicts with just-as-firm data obtained by Europe’s Planck astronomical probe.

According to Planck, the present universe should be expanding at a rate of 67 kilometers per second per megaparsec. According to Hubble, the actual expansion rate is 74 kilometers per second per megaparsec.

And according to the scientists involved, both data sets are reliable and trustworthy, leaving them baffled at the difference.

“This is not just two experiments disagreeing,” explained [lead researcher and Nobel laureate Adam Riess of the Space Telescope Science Institute (STScI) and Johns Hopkins University, in Baltimore, Maryland.] “We are measuring something fundamentally different. One is a measurement of how fast the universe is expanding today, as we see it. The other is a prediction based on the physics of the early universe and on measurements of how fast it ought to be expanding. If these values don’t agree, there becomes a very strong likelihood that we’re missing something in the cosmological model that connects the two eras.”

Ya think? Any cosmologist who claims we really understand what is going on, based on our present fragile and very limited knowledge, is either fooling him or herself or is trying to fool us.

I should note that there seems to be an effort, based on the press release above as well as this second one, to downplay the amount of uncertainties that exist in this cosmological work. Both releases fail to note that when scientists announced their first expansion rate estimate from Hubble’s first data back in 1995, those scientists claimed with absolute certainty that the expansion rate was 80 kilometers per second per megaparsec. At the time some scientists, led by the late Allan Sandage of the Carnegie Observatory, disputed this high number, claiming the number could be as low as 50. Some even said it could be as low as 30 kilometers. Sandage especially found himself poo-pooed by the cosmological community for disputing that the 80 number pushed by Hubble’s scientists in 1995.

In the end, the Hubble scientists in 1995 were closer to today’s Hubble number than Sandage, but his estimate was not wrong by that much more, and he was right when he said the number had to be lower. Either way, Hubble’s modern estimate of 74 for the present expansion rate is very well constrained, and is a far more trustworthy number than previous estimates.

However, do we know with any reliability what the expansion rate was billions of years ago? No. Cosmologists think it was faster, based on supernovae data, which is where the theory of dark energy comes from. It is also where Planck’s predictions come from.

That early expansion rate, however, is based on such tentative data, containing so many assumptions and such large margins of error, that no serious scientist should take it too seriously. It suggests things, but it certainly doesn’t confirm them.

This is why their faith in the numbers derived from Planck puzzles me. It is based on a “prediction,” as Riess admits in the quote above, which means it is based on a theoretical model. It is also based on that very tentative early supernovae data, which makes it very suspect to me.

The Hubble data is real data, obtained by looking at nearby stars in a very precise matter. Its margin of error is very small. It contains only a few assumptions, mostly involving our understanding of the Cepheid variable stars that Hubble observed. While skepticism is always called for, trusting this new Hubble data more is perfectly reasonable.

In the end, to really solve this conflict will require better data from the early universe. Unfortunately, that is not something that will be easy to get.

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Hubble celebrates 29 years in orbit

10:01 am

Hubble's 29th anniversary image

Click for full image.

In celebration of the 29th anniversary of the launch of the Hubble Space Telescope, the Space Telescope Science Institute (STScI) that operates the telescope has released a new image of one of the more spectacular astronomical objects in the southern hemisphere, what astronomers have dubbed the Southern Crab Nebula. I have cropped and reduced the image slightly to post it to the right.

The nebula, officially known as Hen 2-104, is located several thousand light-years from Earth in the southern hemisphere constellation of Centaurus. It appears to have two nested hourglass-shaped structures that were sculpted by a whirling pair of stars in a binary system. The duo consists of an aging red giant star and a burned-out star, a white dwarf. The red giant is shedding its outer layers. Some of this ejected material is attracted by the gravity of the companion white dwarf.

The result is that both stars are embedded in a flat disk of gas stretching between them. This belt of material constricts the outflow of gas so that it only speeds away above and below the disk. The result is an hourglass-shaped nebula.

The bubbles of gas and dust appear brightest at the edges, giving the illusion of crab leg structures. These “legs” are likely to be the places where the outflow slams into surrounding interstellar gas and dust, or possibly material which was earlier lost by the red giant star.

The outflow may only last a few thousand years, a tiny fraction of the lifetime of the system. This means that the outer structure may be just thousands of years old, but the inner hourglass must be a more recent outflow event. The red giant will ultimately collapse to become a white dwarf. After that, the surviving pair of white dwarfs will illuminate a shell of gas called a planetary nebula.

Hubble first revealed this nebula’s shape in a photograph taken in 1999.

The telescope was initially designed for a fifteen year mission. It is about to double that, assuming its last remaining gyroscopes can hold on through next year.

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Five exoplanets discovered with orbits from 15 to 40 years long

9:30 am

Twenty years of observations have now resulted in the discovery of five exoplanets with long solar orbits ranging from 15 to 40 years.

“As early as 1998, a planetary monitoring programme was set up and carried out scrupulously by the many … observers [using the EULER telescope belonging to Geneva University, Switzerland,] who took turns every two weeks in La Silla [Chile] for 20 years”, says Emily Rickman. The result is remarkable: five new planets have been discovered and the orbits of four others known have been precisely defined. All these planets have periods of revolution between 15.6 and 40.4 years, with masses ranging approximately from 3 to 27 times that of Jupiter. This study contributes to increasing the list of 26 planets with a rotation period greater than 15 years.

The press release is very poorly written. It does not explain how 21 years of observations pinpointed the orbit of an exoplanet of forty years. I suspect they have seen enough of the star’s wobble to extrapolate that orbit, but the press release should have explained this.

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Did an interstellar meteor hit the Earth in 2014?

5:55 am

By analyzing the speed in which it traveled through the atmosphere, astronomers propose that a meteor that hit the ground in 2014 was probably an interstellar object.

The scientists analyzed the Center for Near-Earth Object Studies’ catalog of meteor events detected by U.S. government sensors. They focused on the fastest meteors, because a high speed suggests a meteor is potentially not gravitationally bound to the sun and thus may originate from outside the solar system.

The researchers identified a meteor about 3 feet (0.9 meters) wide that was detected on Jan. 8, 2014, at an altitude of 11.6 miles (18.7 kilometers) over a point near Papua New Guinea’s Manus Island in the South Pacific. Its high speed of about 134,200 mph (216,000 km/h) and its trajectory suggested it came from outside the solar system, the scientists said. “We can use the atmosphere of the Earth as the detector for these meteors, which are too small to otherwise see,” Loeb told Space.com.

The meteor’s velocity suggested it received a gravitational boost during its journey, perhaps from the deep interior of a planetary system, or a star in the thick disk of the Milky Way.

To put it mildly, there are a lot of uncertainties about this conclusion. Nonetheless, their approach and hypothesis is very intriguing, and seems logical.

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Tess finds Earth-sized planet?

9:24 am

Scientists using the space telescope TESS think they may have found its first Earth-sized planet.

Its host star has about 80 percent of the mass of our Sun and is found about 53 light-years distant from Earth. HD 21749b has about 23 times Earth’s mass and a radius of about 2.7 times Earth’s. Its density indicates the planet has substantial atmosphere but is not rocky, so it could potentially help astronomers understand the composition and evolution of cooler sub-Neptune planet atmospheres.

Excitingly, the longer period sub-Neptune planet in this system is not alone. It has a sibling planet, HD 21749c, which takes about eight days to orbit the host star and is much smaller—similar in size to Earth. “Measuring the exact mass and composition of such a small planet will be challenging, but important for comparing HD 21749c to Earth,” said Wang. “Carnegie’s PFS team is continuing to collect data on this object with this goal in mind.”

In other words, they know almost nothing yet about the smaller exoplanet. They think it is similar in size to the Earth, but they don’t know its mass or composition.

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Astronomers take highest resolution radio image of black hole

9:54 am

shadow of black hole

Using a network of ground-based radio telescopes astronomers today released the highest resolution radio image of black hole ever produced.

Before giving more details, I must correct every other news report, as well as all of the press releases about this image. It is not “The first image of a black hole!” as these releases are claiming breathlessly. Radio telescope arrays have taken such images in the past, but their resolution was poor, so the result was not very imagelike. Instead, it showed contour lines in a coarse manner. Moreover, the coarseness of the resolution prevented them from seeing the black hole’s shadow itself.

This image now produced has the highest resolution ever for such a radio image, but believe me, it is still coarse. Nonetheless, it represents a giant technological leap forward. The effort required upgrades to many of these telescopes, along with significantly improved computer analysis. Now for some details:

Black holes are extraordinary cosmic objects with enormous masses but extremely compact sizes. The presence of these objects affects their environment in extreme ways, warping spacetime and super-heating any surrounding material. “If immersed in a bright region, like a disc of glowing gas, we expect a black hole to create a dark region similar to a shadow — something predicted by Einstein’s general relativity that we’ve never seen before,” explained chair of the EHT Science Council Heino Falcke of Radboud University, the Netherlands. “This shadow, caused by the gravitational bending and capture of light by the event horizon, reveals a lot about the nature of these fascinating objects and allowed us to measure the enormous mass of M87’s black hole.”

The image reveals the black hole at the center of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster. This black hole resides 55 million light-years from Earth and has a mass 6.5-billion times that of the Sun.

…Multiple calibration and imaging methods have revealed a ring-like structure with a dark central region — the black hole’s shadow — that persisted over multiple independent EHT observations. “Once we were sure we had imaged the shadow, we could compare our observations to extensive computer models that include the physics of warped space, superheated matter and strong magnetic fields. Many of the features of the observed image match our theoretical understanding surprisingly well,” remarks Paul T.P. Ho, EHT Board member and Director of the East Asian Observatory. “This makes us confident about the interpretation of our observations, including our estimation of the black hole’s mass.” [emphasis mine]

Note the highlighted words. To create this image they needed to combine data from numerous radio telescopes. Such work requires extensive calibration. The resulting image is manufactured, though without doubt it is manufactured from real radio data accumulated by multiple telescopes. Because those telescopes are separated by distance, however, there will always be gaps between their images, and it is in the calibration and imaging methods that the gaps are extrapolated away.

I don’t wish to imply that this image is fake. It is not. That the features persisted over multiple observations confirms that they were actually seeing the black hole’s shadow. It also confirms that these new interferometry techniques work.

However, much of the press hyperbole today is an effort to justify the many millions in tax dollars spent on this effort. The effort was absolutely worthwhile scientifically, but government bureaucracies always feel a need to oversell their work. That is partly what is happening here.

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Fragment of a long dead planet’s iron core found orbiting white dwarf

8:25 am

Astronomers have identified the fragment of a long dead planet’s iron core orbiting a white dwarf star 410 light years away.

The [data] suggested its source was a solid object some 600 kilometers across—a suspected planetary core, with a density between 7.7 and 39 grams per cubic meter, comparable to the pure iron found within Earth’s core. “The density of the piece of rock is consistent with what we think the cores of planets [are],” says Luca Fossati of the Austrian Academy of Sciences, who was not involved in the paper.

It orbits the star every two hours, the fastest exoplanet orbit yet found. This alone should rip it apart, providing further evidence that the object’s density is very high.

The astronomers theorize that this object is likely the remains of a planet that existed when this star was young, and was destroyed as the star aged to become a red giant, expanding to swallow it. Later, when the star collapsed to become a tiny white dwarf, the core remained, its density allowing it survive as the planet’s outer crust was torn away.

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Telescope store sues Asian telescope manufacturers for fixing prices

11:21 am

A San Francisco store that sells telescopes to the public is suing two Asian telescope manufacturers — who make almost all recreational telescopes sold in the U.S. — for conspiring together to fix prices and create that monopoly.

Orion Telescopes and Binoculars, which is headquartered in Watsonville and has stores there and in Cupertino, is seeking more than $180 million in damages in a lawsuit. A federal court in Northern California said the complaint against telescope maker Ningbo Sunny, filed in 2016, can go to trial. A subsidiary of Ningbo Sunny, a Chinese company, bought Irvine telescope maker Meade Instruments in 2013.

In the complaint, Orion alleges that Ningbo Sunny and a Taiwanese telescope manufacturer, Synta Technology, shared confidential information that competitors normally would not share, including product pricing, order forecasts and credit arrangements.

My question is this: Why are no American telescope manufacturers competing in this market? Are our labor costs too high? Our government regulations too restrictive? A little bit of competition could easily end this collusion by these Asian manufacturers, assuming it is happening.

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Hubble’s main camera resumes science work

8:41 am

The main camera on the Hubble Space Telescope has resumed science operations after going into safe mode last week.

At 8:31 p.m. EST on Feb. 28, the Advanced Camera for Surveys aboard NASA’s Hubble Space Telescope suspended operations after an error was detected as the instrument was performing a routine boot procedure. The error indicated that software inside the camera had not loaded correctly in a small section of computer memory. The Hubble operations team ran repeated tests to reload the memory and check the entire process. No errors have been detected since the initial incident, and it appears that all circuits, computer memory and processors that are part of that boot process are now operating normally. The instrument has now been brought back to its standard operating mode for normal operations.

From the press release, it appears that they have not been able to trace why the error occurred. However, much like a typical Windows computer, after a mysterious crash and reboot now all appears well, so they have shrugged their shoulders and moved on.

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