Tag: astronomy

Engineers: Webb undamaged by “incident”, ready for December 22nd launch

9:46 am

Arianespace engineers have confirmed after testing that the James Webb Space Telescope was undamaged by “incident” that occurred during stacking, and have okayed the resumption of the telescope’s preparation for launch.

On Wednesday, Nov. 24, engineering teams completed these tests, and a NASA-led anomaly review board concluded no observatory components were damaged in the incident. A “consent to fuel” review was held, and NASA gave approval to begin fueling the observatory. Fueling operations will begin Thursday, Nov. 25, and will take about 10 days.

The launch is now set for December 22nd.

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Second camera on Hubble returned to science operations

10:35 am

Engineers working to reactivate the instruments on the Hubble Space Telescope have successfully brought a second camera out of safe mode.

NASA continues bringing the Hubble Space Telescope back to normal science operations, most recently recovering the Wide Field Camera 3 instrument Sunday, Nov. 21. This camera will be the second of Hubble’s instruments, after the Advanced Camera for Surveys, to resume science after suspending the spacecraft’s observations Oct. 25. The Wide Field Camera 3’s first science observation since the anomaly will be Nov. 23.

The team chose to restore the most heavily used Hubble instrument, the Wide Field Camera 3, which represents more than a third of the spacecraft’s observing time. Engineers also began preparing changes to the instrument parameters, while testing the changes on ground simulators. These changes would allow the instruments to handle several missed synchronization messages while continuing to operate normally if they occur in the future. These changes will first be applied to another instrument, the Cosmic Origins Spectrograph, to further protect its sensitive far-ultraviolet detector. It will take the team several weeks to complete the testing and upload the changes to the spacecraft.

The telescope’s other instruments remain in safe mode as the engineers continue to investigate the problem that caused the shut down on October 25th.

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Webb launch delayed four days because of “incident” during stacking

2:18 pm

NASA management has decided to delay the launch of the James Webb Space Telescope for four days while engineers investigate whether an “incident” that occurred during the telescope’s stacking on top of an Ariane 5 rocket could have long term consequences.

Technicians were preparing to attach Webb to the launch vehicle adapter, which is used to integrate the observatory with the upper stage of the Ariane 5 rocket. A sudden, unplanned release of a clamp band – which secures Webb to the launch vehicle adapter – caused a vibration throughout the observatory.

A NASA-led anomaly review board was immediately convened to investigate and instituted additional testing to determine with certainty the incident did not damage any components. NASA and its mission partners will provide an update when the testing is completed at the end of this week.

The launch had been scheduled for December 18th. They have now pushed it back to December 22nd.

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Hubble operations contract extended to 2026, even as engineers work to fix it

3:10 pm

NASA announced today that it has extended the contract for operating the Hubble Space Telescope through 2026, even as it also provided an update on the effort of engineers to bring all the telescope’s science instruments out of safe mode.

[T]he agency has awarded a sole source contract extension to the Association of Universities for Research in Astronomy (AURA) in Washington for continued Hubble science operations support at the Space Telescope Science Institute (STScI) in Baltimore, which AURA operates for NASA. The award extends Hubble’s science mission through June 30, 2026, and increases the value of the existing contract by about $215 million (for a total of about $2.4 billion).

…Currently, the spacecraft team at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is investigating an issue involving missed synchronization messages that caused Hubble to suspend science observations Oct. 25. One of the instruments, the Advanced Camera for Surveys, resumed science observations Nov. 7, and continues to function as expected. All other instruments remain in safe mode.

During the week of Nov. 8, the Hubble team identified near-term changes that could be made to how the instruments monitor and respond to missed synchronization messages, as well as to how the payload computer monitors the instruments. This would allow science operations to continue even if several missed messages occur. The team has also continued analyzing the instrument flight software to verify that all possible solutions would be safe for the instruments.

In the next week, the team will begin to determine the order to recover the remaining instruments. The team expects it will take several weeks to complete the changes for the first instrument.

It appears that it is going to take some time to bring all the instruments back in line, considering that they are fixing the instruments one-by-one, in sequence, and that the first fix is taking weeks. Hopefully as they get each instrument back they will be able to move faster once they know what works.

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Hubble camera back in operation

2:16 pm

Good news! As engineers work to fix the problem that caused the Hubble Space Telescope to shut down on October 25th, they have now successfully returned Hubble’s most important camera back to doing science.

The Hubble team successfully recovered the Advanced Camera for Surveys instrument Nov. 7. The instrument has started taking science observations once again. Hubble’s other instruments remain in safe mode while NASA continues investigating the lost synchronization messages first detected Oct. 23. The camera was selected as the first instrument to recover as it faces the fewest complications should a lost message occur.

This success strongly suggests they have pinpointed the software issue that caused the shutdown, and can now step-by-step reactivate all the other instruments in the coming week.

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New catalog of 90 gravitational wave detections published

9:24 am

The scientists operating the world’s three gravitational wave detectors today released a new catalog of all their detections, totaling 90 with 35 never before published.

All signals come from merging black holes and neutron stars. The new catalog contains some surprises, such as an unusual neutron-star–black-hole merger, a massive black hole merger, and binary black holes revealing information about their spins.

…The researchers have also published two papers accompanying their new catalog today. One looks at what the events can tell us about the population of compact objects in our Universe, how often they merge, and how their masses are distributed. In the other paper the researchers employed the gravitational waves to better understand the expansion history of the cosmos by measuring the Hubble constant.

Because of the tiny sample so far detected, these generalized results cannot be taken too seriously, though they do give hints at the larger context.

All three observatories are now undergoing upgrades, and will resume operations in a few weeks.

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Astronomers release fantasy proposals for government telescopes in the 2020s

8:54 am

The astronomical community today released its newest decadal survey, a outline of what major new telescope projects that community recommends the federal government should fund for the next ten years.

More details here.

This is I think the seventh such decadal survey since the first in the early 1960s. In the past these surveys prompted the construction of numerous space telescopes, such as the Hubble Space Telescope, the James Webb Space Telescope, and many others. Until 2000 these survey were enormously influential, which is why space-based astronomy boomed in the 1980s and 1990s.

Now I call it a fantasy because I think it unlikely that most of its proposals — especially the space-based projects — will see fruition, based on the recent history in this century. For example, the 2001 survey recommended the James Webb Space Telescope among many other recommendations. The cost overruns of that project however eventually caused almost all the other space-based proposals to be cancelled, not only in the 2000s but in the 2010s as well. Furthermore, the 2010 survey called for the building of WFIRST, another Webb-like big space telescope that is now called the Roman Telescope, and that project’s high cost and complexity has further forced the elimination of almost all other new space telescopes. Nor has Roman been built and launched in the 2010s as proposed. It is still under development, with the same kinds of cost orverruns and delayed seen with Webb, which means in the 2020s most of the new proposals in this latest decadal survey will have to take a back seat to it, and will likely never get built.

Prove of my analysis is in the report’s press release:

The first mission to enter this program should be an infrared/optical/ultraviolet (IR/O/UV) telescope — significantly larger than the Hubble Space Telescope — that can observe planets 10 billion times fainter than their star, and provide spectroscopic data on exoplanets, among other capabilities. The report says this large strategic mission is of an ambitious scale that only NASA can undertake and for which the U.S. is uniquely situated to lead. At an estimated cost of $11 billion, implementation of this IR/O/UV telescope could begin by the end of the decade, after the mission and technologies are matured, and a review considers it ready for implementation. If successful, this would lead to a launch in the first half of the 2040 decade. [emphasis mine]

Proposing something that won’t be built for two decades is absurd. And the cost is even more absurd, as it is ten times what Hubble cost and seems more designed as a long term jobs program where nothing will get built but money will continue to pour in endlessly to the contractors and astronomers hired. That is what Webb and Roman essentially became.

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Astronomers detect water in the very very early universe

9:14 am

The uncertainty of science: Using the ALMA telescope in Chile, astronomers have detected the molecules of water and carbon monoxide in a galaxy thought to have formed only 780 million years after the Big Bang.

SPT0311-58 is actually made up of two galaxies and was first seen by ALMA scientists in 2017 at its location, or time, in the Epoch of Reionization. This epoch occurred at a time when the Universe was just 780 million years old—roughly 5-percent of its current age—and the first stars and galaxies were being born. Scientists believe that the two galaxies may be merging, and that their rapid star formation is not only using up their gas, or star-forming fuel but that it may eventually evolve the pair into massive elliptical galaxies like those seen in the Local Universe.

“Using high-resolution ALMA observations of molecular gas in the pair of galaxies known collectively as SPT0311-58 we detected both water and carbon monoxide molecules in the larger of the two galaxies. Oxygen and carbon, in particular, are first-generation elements, and in the molecular forms of carbon monoxide and water, they are critical to life as we know it,” said Sreevani Jarugula, an astronomer at the University of Illinois and the principal investigator on the new research. “This galaxy is the most massive galaxy currently known at high redshift, or the time when the Universe was still very young. It has more gas and dust compared to other galaxies in the early Universe, which gives us plenty of potential opportunities to observe abundant molecules and to better understand how these life-creating elements impacted the development of the early Universe.”

Need I say that there are many uncertainties with this result, including the assumption that the universe is only 780 million years old at location of this galaxy. That age is extrapolated from the galaxy’s red shift, a link that depends on some uncertain assumptions. Moreover, the discovery of these molecules so soon after the theorized Big Bang is unexpected. Cosmologists had assumed that at this early age the universe wasn’t old enough yet to form galaxies with such complex molecules.

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Hubble still in safe mode

9:05 am

NASA released a new but relatively terse update on November 1st describing the status of the Hubble Space Telescope, which has been in safe mode since October 25th.

Hubble’s science instruments issued error codes at 1:46 a.m. EDT Oct. 23, indicating the loss of a specific synchronization message. This message provides timing information the instruments use to correctly respond to data requests and commands. The mission team reset the instruments, resuming science operations the following morning.

At 2:38 a.m. EDT, Oct. 25, the science instruments again issued error codes indicating multiple losses of synchronization messages. As a result, the science instruments autonomously entered safe mode states as programmed.

Mission team members are evaluating spacecraft data and system diagrams to better understand the synchronization issue and how to address it. They also are developing and testing procedures to collect additional data from the spacecraft. These activities are expected to take at least one week.

In other words, the engineers presently do not understand the problem, and are working at pinpointing its cause.

This is not a “glitch”. If used properly that word really refers to something that is akin to a short burp in operations. Hubble has been shut down now for ten days, and will remain so for at least one more week. This is a serious problem that remains unsolved.

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Evidence from nearby white dwarfs suggest rocky exoplanets are alien to Earth

10:15 am

The uncertainty of science: Evidence from 23 white dwarfs, all located less than 650 light years from Earth, suggest that the make-up of rocky exoplanets are likely very alien to Earth, with minerals and chemistry that is found nowhere in our solar system.

They found that these white dwarfs have a much wider range of compositions than any of the inner planets in our solar system, suggesting their planets had a wider variety of rock types. In fact, some of the compositions are so unusual that Putirka and Xu had to create new names (such as “quartz pyroxenites” and “periclase dunites”) to classify the novel rock types that must have existed on those planets.

“While some exoplanets that once orbited polluted white dwarfs appear similar to Earth, most have rock types that are exotic to our solar system,” said Xu. “They have no direct counterparts in the solar system.”

Putirka describes what these new rock types might mean for the rocky worlds they belong to. “Some of the rock types that we see from the white dwarf data would dissolve more water than rocks on Earth and might impact how oceans are developed,” he explained. “Some rock types might melt at much lower temperatures and produce thicker crust than Earth rocks, and some rock types might be weaker, which might facilitate the development of plate tectonics.”

The data from the white dwarfs is believed to be the leftover material of exoplanets that were absorbed by the star, sometime in the far past.

First, this result should not be a surprise. To even think for a second that planets in other solar systems would be similar to the planets in our solar system is unrealistic. Even in our solar system we have found that practically every single body — planets, moons, asteroids, comets — is remarkably unique. Other solar systems are sure to be even more alien.

Second, the result here is somewhat uncertain. The scientists were not gathering data of actual exoplanets, but what is believed to be the remains that had been swallowed by the stars. The scientists then extrapolated backwards to come up with these alien rock types. The result, while very suggestive, must be taken with some skepticism.

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Astronomers: If there are artificial Dyson spheres out there, we can detect them

8:55 am

In a preprint science paper published on October 26, 2021, astronomers review the impact a Dyson sphere might have on its central star and conclude that modern astronomical instruments should be able to identify these changes. From the abstract:

The search for signs of extraterrestrial technology, or technosignatures, includes the search for objects which collect starlight for some technological use, such as those composing a Dyson sphere. These searches typically account for a star’s light and some blackbody temperature for the surrounding structure. However, such a structure inevitably returns some light back to the surface of its star, either from direct reflection or thermal re-emission. In this work, we explore how this feedback may affect the structure and evolution of stars, and when such feedback may affect observations. We find that in general this returned light can cause stars to expand and cool. Our MESA models show that this energy is only transported toward a star’s core effectively by convection, so low mass stars are strongly affected, while higher mass stars with radiative exteriors are not. Ultimately, the effect only has significant observational consequences for spheres with very high temperatures (much higher than the often assumed ~300 K) and/or high specular reflectivity. Lastly, we produce color-magnitude diagrams of combined star-Dyson sphere systems for a wide array of possible configurations.

A plain-language description of the paper can be found here, which summarizes this work as follows:

This study shows that Dyson spheres can result in measurable changes to stellar properties. Megastructures have long been confined to science fiction, imagination and certain video games. However, if there are indeed Dyson spheres out there waiting to be found, we could soon be in a position to find them.

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Hubble in safe mode again

10:50 pm

According to NASA’s Twitter feed for the Hubble Space Telescope, it went into safe mode earlier this week because of “issues with internal communications.”

Hubble’s science instruments went into safe mode on Monday after experiencing synchronization issues with internal spacecraft communications. Science observations have been temporarily suspended while the team investigates the issue. The instruments remain in good health.

Much of the press is using that lovely buzzword of bureaucrats, calling this a “glitch.” The goal of that word is to make the problem seem minor and no big deal.

It can’t be minor and no big deal however if the telescope shut down six days ago and remains out of service. This is not a “glitch.” This is a serious issue that is taking time to resolve.

Furthermore, I get more concerned when no further information is provided. As far as I can so far find, the quote above is the only information NASA has released. And that information is remarkably vague and uninformative.

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Water and carbon monoxide detected in exoplanet’s atmosphere

9:54 am

Astronomers, using both the Hubble Space Telescope and the ground-based Gemini Telescope, have detected water and carbon monoxide in the atmosphere of an exoplanet 320 light years away.

Previously hydrogen, helium, hydrogen cyanide, iron, and magnesium have been detected in the atmospheres of a variety of exoplanets. In other cases scientists found exoplanets that were devoid of water.

This detection of water and carbon monoxide is a first for these two materials, and is somewhat significant as it is the first detection that suggests an exoplanet atmosphere that might have similarities to Earth.

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First exoplanet detected in another galaxy?

8:32 am

The uncertainty of science: Using the Chandra X-ray Observatory, astronomers think they may have detected the first exoplanet ever found in another galaxy, the Whirlpool Galaxy, 28 million light years away.

This new result is based on transits, events in which the passage of a planet in front of a star blocks some of the star’s light and produces a characteristic dip. Astronomers using both ground-based and space-based telescopes — like those on NASA’s Kepler and TESS missions — have searched for dips in optical light, electromagnetic radiation humans can see, enabling the discovery of thousands of planets.

Di Stefano and colleagues have instead searched for dips in the brightness of X-rays received from X-ray bright binaries. These luminous systems typically contain a neutron star or black hole pulling in gas from a closely orbiting companion star. The material near the neutron star or black hole becomes superheated and glows in X-rays.

Because the region producing bright X-rays is small, a planet passing in front of it could block most or all of the X-rays, making the transit easier to spot because the X-rays can completely disappear. This could allow exoplanets to be detected at much greater distances than current optical light transit studies, which must be able to detect tiny decreases in light because the planet only blocks a tiny fraction of the star.

The team used this method to detect the exoplanet candidate in a binary system called M51-ULS-1, located in M51. This binary system contains a black hole or neutron star orbiting a companion star with a mass about 20 times that of the Sun. The X-ray transit they found using Chandra data lasted about three hours, during which the X-ray emission decreased to zero. Based on this and other information, the researchers estimate the exoplanet candidate in M51-ULS-1 would be roughly the size of Saturn, and orbit the neutron star or black hole at about twice the distance of Saturn from the Sun.

While this is a tantalizing study, more data would be needed to verify the interpretation as an extragalactic exoplanet. One challenge is that the planet candidate’s large orbit means it would not cross in front of its binary partner again for about 70 years, thwarting any attempts for a confirming observation for decades. [emphasis mine]

As the press release says, this data is tantalizing, but it is really insufficient to prove that an exoplanet has been found. What is known is that for some reason the X-ray emissions from the X-ray binary system disappeared for about three hours. An exoplanet could be one explanation. So could many other things.

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Next Ariane 5 launch postponed

11:39 am

Arianespace today announced that it has postponed its next Ariane 5 launch of two communications satellites, scheduled for October 22nd, because of issues with ground equipment.

Though there appear to be no issues with the rocket, this delay could effect the launch of the James Webb Space Telescope in December on another Ariane 5 rocket. Arianespace has said that it wants to complete this launch first, to make sure the fixes it completed on the rocket’s fairing are truly working.

It was those problems that shut down all Ariane 5 launches for almost a full year.

No new launch date has been set. Normally, ground equipment issues cause short delays, so we should be hopeful all will be fixed quickly and this launch will be quickly rescheduled and take off without problems.

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Early solar system had gap separating its inner and outer regions

9:29 am

New research looking at the make-up of asteroids now suggests that the early solar system had a gap that separated the formation of planets between its inner and outer regions.

Earlier data had suggested that asteroids come in two fundamentally different groups. This new research, looking the magnetic field strength of these two groups, has confirmed this distinction, and provided additional information about the formation process of each.

Surprisingly, they found that their field strength was stronger than that of the closer-in noncarbonaceous meteorites they previously measured. As young planetary systems are taking shape, scientists expect that the strength of the magnetic field should decay with distance from the sun.

In contrast, Borlina and his colleagues found the far-out chondrules had a stronger magnetic field, of about 100 microteslas, compared to a field of 50 microteslas in the closer chondrules. For reference, the Earth’s magnetic field today is around 50 microteslas.

A planetary system’s magnetic field is a measure of its accretion rate, or the amount of gas and dust it can draw into its center over time. Based on the carbonaceous chondrules’ magnetic field, the solar system’s outer region must have been accreting much more mass than the inner region.

In other words, the accretion of planets in the outer region was faster and producing larger objects, while the inner region was slower and producing smaller objects. The data also suggests that gap existed about 4.5 billion years ago, at about the location of the asteroid belt. All in all, this scenario matches the solar system we see today.

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Webb telescope finally arrives at launch site in French Guiana

2:54 pm

Webb deployment

After almost twenty years of construction (a decade behind schedule) and a cost of $10 billion, ($9.5 billion over budget), the James Webb Space Telescope today arrived at the processing facility at Arianespace’s French Guiana spaceport, where it will be prepared for a December 18, 2021 launch on an Ariane 5 rocket.

Once launched the telescope, which is not a replacement for Hubble because it observes in the infrared (not optical) and is optimized for deep space cosmology, will take two weeks to reach its orbital position about a million miles from Earth, as shown in the graphic.

Let us all cross our fingers and toes that it all works as designed, for if it doesn’t this will be the biggest failure ever in the history of NASA.

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As expected, Pluto’s atmosphere is freezing as its orbit takes it from the Sun

10:48 am

Data from ground-based telescopes has now confirmed that Pluto’s nitrogen atmosphere has begun it annual winter freeze out as the planet’s somewhat elliptical 248-year-long orbit takes it away from the Sun.

For about 25 years, Pluto has been moving farther and farther away from the sun, so its surface temperature has been going down. And with these recent observations, the researchers found evidence showing that Pluto’s atmosphere is actually refreezing back onto its surface as the dwarf planet gets colder and colder. Pluto is so far from the sun that, as time goes on, it will get distinctly farther away (and colder) before getting closer to the sun in other regions of its immense orbit.

The astronomers were able to detect this refreezing by observing the planet as it eclipsed a star in 2018.

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New Horizons discovers two binary asteroids in Kuiper Belt

10:32 am

Overview map
Click for full map.

As New Horizons traveled from Pluto to the asteroid Arrokoth in 2018, scientists used it to take images of the relatively nearby asteroids that it was passing, and found that two of those asteroids appeared elongated.

[T]he team fit the shapes with a two-body model: two asteroids in a tight orbit. Even though the individual rocks weren’t resolved, the modeling showed that two bodies were better able to explain the elongation, as well as the brightness seen. The model for 2011 JY31 had two 50-km-wide objects nearly 200 km apart, while for 2014 OS393, the model had slightly smaller bodies (30 km across) that orbited each other 150 km apart.

The map, cropped and further annotated by me, shows New Horizons’ path during this time period, with the two binary asteroids indicated in blue.

This data, combined with the double lobe shape of Arrokoth (formerly named Ultima Thule), strongly suggests that it was not unusual for these primitives asteroids in the early solar system to coalesce from comparably sized partners.

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Orbit of biggest comet ever detected refined

10:59 am

Astronomers have now been able to better refine the orbit and size of Comet Bernardinelli-Bernstein, comet with the largest nucleus ever detected.

A new analysis, led by Bernardinelli and Bernstein themselves, found that the comet nucleus is around 150 km wide, based on its brightness. If so, that makes it the largest comet ever discovered, by quite a margin. Most are only a few kilometers to several dozen kilometers wide, while some particularly big ones, like Hale-Bopp, may be up to 80 km (50 miles) wide. The previous record-holder, Sarabat’s Comet of 1729, has been estimated at about 100 km wide.

The team was also able to calculate the orbit of Comet BB in more detail. This object is on an incredibly long round trip into and out of the solar system – at its most distant point, some 1.5 million years ago, it was about 40,400 AU away. Last time it swung through our neighborhood was about 3.5 million years ago, when it came within 18 AU of the Sun.

But its current inward journey will be its closest so far. Astronomers have already calculated that in 2031, Comet BB will peak at 10.9 AU, almost reaching the orbit of Saturn.

It is presently unclear how bright the comet will be when it reachest its closest point. It will be much farther from the Sun than most bright comets, but its large size may change what is normally expected.

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Galaxies in the early universe don’t fit the theories

9:33 am

The uncertainty of science: New data from both the ALMA telescope in Chile and the Hubble Space Telescope about six massive galaxies in the early universe suggest that there are problems and gaps in the presently accepted theories about the universe’s formation.

Early massive galaxies—those that formed in the three billion years following the Big Bang should have contained large amounts of cold hydrogen gas, the fuel required to make stars. But scientists observing the early Universe with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Hubble Space Telescope have spotted something strange: half a dozen early massive galaxies that ran out of fuel. The results of the research are published today in Nature.

Known as “quenched” galaxies—or galaxies that have shut down star formation—the six galaxies selected for observation from the REsolving QUIEscent Magnified galaxies at high redshift. or the REQUIEM survey, are inconsistent with what astronomers expect of the early Universe.

It was expected that the early universe would have lots of that cold hydrogen for making stars. For some galaxies to lack that gas is inexplicable, and raises questions about the assumptions inherent in the theory of the Big Bang. It doesn’t disprove it, it simply makes it harder to fit the facts to the theory, suggesting — as is always the case — that the reality is far more complicated than the theories of scientists.

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NASA now targets December 18, 2021 for launch of Webb

1:12 pm

NASA today announced that it and the European Space Agency have scheduled the Ariane 5 launch of the James Webb Space Telescope from French Guiana for December 18, 2021.

The agency set the new target launch date in coordination with Arianespace after Webb recently and successfully completed its rigorous testing regimen – a major turning point for the mission. The new date also follows Arianespace successfully launching an Ariane 5 rocket in late July and scheduling a launch that will precede Webb. The July launch was the first for an Ariane 5 since August 2020.

Launching before the end of ’21 will allow NASA to claim that Webb is only be ten years behind schedule, not eleven. The cost overruns however remain astronomical (no pun intended). Initially budgeted at $500 million, Webb is now estimated to have cost $10 billion.

Once launched the telescope will take about six months to slowly move to its Lagrange point location about a million miles from the Earth, in the Earth’s shadow. During that time it will also be steadily deploying its many segmented mirror for infrared observations (an important detail as Webb is not a replacement for Hubble, which does most of its observations in the optical wavelengths).

Should deployment and placement go as planned, Webb will undoubtedly do ground-breaking astronomy, especially in the field of deep space cosmology. If anything should go wrong, any repair mission will take at a minimum five years to mount, if ever.

Keep those fingers and toes crossed!

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Astronomers discover white dwarf stars still burning hydrogen

9:50 am

The uncertainty of science: Using Hubble observations of the white dwarfs in two different globular clusters, astronomers have discovered that — contrary to the consensus opinion — some white dwarf stars are not slowly cooling embers of a dead star, but are still generating nuclear fusion by burning hydrogen in their outer layers.

Using Hubble’s Wide Field Camera 3 the team observed [globular clusters] M3 and M13 at near-ultraviolet wavelengths, allowing them to compare more than 700 white dwarfs in the two clusters. They found that M3 contains standard white dwarfs, which are simply cooling stellar cores. M13, on the other hand, contains two populations of white dwarfs: standard white dwarfs and those which have managed to hold on to an outer envelope of hydrogen, allowing them to burn for longer and hence cool more slowly.

Comparing their results with computer simulations of stellar evolution in M13, the researchers were able to show that roughly 70% of the white dwarfs in M13 are burning hydrogen on their surfaces, slowing down the rate at which they are cooling.

This discovery could have consequences for how astronomers measure the ages of stars in the Milky Way galaxy. The evolution of white dwarfs has previously been modeled as a predictable cooling process. This relatively straightforward relationship between age and temperature has led astronomers to use the white dwarf cooling rate as a natural clock to determine the ages of star clusters, particularly globular and open clusters. However, white dwarfs burning hydrogen could cause these age estimates to be inaccurate by as much as 1 billion years.

In other words, many past age estimates for star clusters could be very wrong, which in turn could mean the general understanding of the evolution of these objects could be very wrong as well.

These results also illustrate a fact that astronomers seem to always forget. The stars in any one category (white dwarfs, red super giants, yellow stars like the Sun, etc.) are not all identical, and thus their life and death processes will not all follow the predicted stages, like clockwork. Things are always far more complicated. Though the predictions might be broadly right, there will be many variations, so many that it will often be difficult to draw a generalized conclusion.

It seems that with white dwarfs astronomers have made this mistake, and now must rethink many of their conclusions.

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The troubled politics of ground-based astronomy

10:54 am

Link here. The article outlines the politics and negotiations now going on during the writing of the next astronomy decadal survey, the document American astronomers have published every decade since the 1960s to provide the science agencies in the federal government guidance on how to spend the taxpayers’ money on the next decade’s astronomy projects.

The focus is on the problems now faced by the two big American ground-based telescopes, the Thirty Meter Telescope (TMT) and the Giant Magellan Telescope (GMT).

The future of the Giant Magellan Telescope (GMT) and the Thirty Meter Telescope (TMT) likely depends on whether the survey recommends that NSF spend what sources put at $1.8 billion to support a recently forged partnership between the projects. If it does, other proposals could lose out, such as a ­continent-spanning radio array and detectors for neutrinos and other cosmic particles.

While some astronomers are pushing for this $1.8 billion bailout to save both, others are arguing the money can be better spent elsewhere. There is also a third option, not mentioned, which would be to abandon one of these telescopes and instead build just one.

The story is focused entirely on ground-based astronomy, which is remarkably very near-sighted for scientists whose job it is to see a far as possible. The future of astronomy is in space, and to not consider that alternative in this discussion means you aren’t considering all your options. For $1.8 billion, using private rockets and competitive construction approaches, I strongly believe a very large optical telescope could be launched that would provide far more cutting edge astronomy than any larger ground-based telescope. Hubble has proven that endlessly for the past thirty years.

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Webb telescope finally completed, ready for shipment to launchpad

2:15 pm

After more than two decades of construction (ten years behind schedule) and more than $10 billion (20 times the original cost), the infrared James Webb Space Telescope has finally completed its testing and is ready for shipment to its launch site in French Guiana to be mounted on an Ariane 5 rocket.

Now that observatory testing has concluded, shipment operations have begun. This includes all the necessary steps to prepare Webb for a safe journey through the Panama Canal to its launch location in Kourou, French Guiana, on the northeastern coast of South America. Since no more large-scale testing is required, Webb’s clean room technicians have shifted their focus from demonstrating it can survive the harsh conditions of launch and work in orbit, to making sure it will safely arrive at the launch pad. Webb’s contamination control technicians, transport engineers, and logistics task forces are all expertly prepared to handle the unique task of getting Webb to the launch site. Shipping preparations will be completed in September.

If all goes well, NASA and ESA hope to launch the telescope in late October. It will then take about six months for the telescope to unfold and reach its operating position a million miles from Earth in the Earth’s shadow.

Let us all pray that everything works. If it does not, there will be nothing that can be done to fix it for probably at least five years, if then, as it will be out of reach of any maintenance mission, manned or unmanned.

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Spanish judge invalids agreement to build TMT in Canary Islands

9:05 am

The consortium attempting to build the Thirty Meter Telescope (TMT), blocked by protesters in Hawaii, has now had its back-up location in the Canary Islands blocked by a Spanish judge, who last month invalidated the agreement between the consortium and local authorities.

[A]n administrative court in Santa Cruz de Tenerife, the capital of the Spanish archipelago, ruled last month that the 2017 concession by local authorities of public land for the tentative project was invalid. The ruling was dated on July 29, but only became public this week after local media reported about the decision.

In the ruling obtained by The Associated Press, Judge Roi López Encinas wrote that the telescope land allocation was subject to an agreement between the Canary Astrophysics Institute, or IAC, and the telescope’s promoter, the TMT International Observatory (TIO) consortium. But the judge ruled that the agreement was not valid because TIO had not expressed an intention to build on the La Palma site instead of at the Hawaii site.

In other words, it appears the agreement was ruled invalid because the TMT builders had not made a firm commitment about building at the Canary Islands.

At this moment it truly looks like TMT is dead. It has no alternative site, and its political support in Hawaii is nil. While the Democratic Party politicians that rule that state have mouthed support for it, almost all their actions since the protests began has been to help the protesters and stymie construction.

What I think will soon begin happening is that the partners in TMT will begin to back out, switching their support to the other large ground-based telescopes being planned, the Giant Magellan Telescope and the European-Extremely Large Telescope. Since these are both being built in Chile, the loss of TMT means that there will be no large ground-based telescope coverage of the northern sky.

The real solution? Stop building ground-based telescopes. Put them in space, where such political issues won’t exist, and the view will be unimpeded by either the atmosphere or the tens of thousands of new satellites expected to launch in the coming years.

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First hi-res radio wavelength images of metal asteroid Psyche

9:46 am

Psyche in thermal

Using the ALMA telescope in Chile astronomers have obtained the highest resolution radio images of the surface of the metal-rich asteroid Psyche yet obtained. The image to the right is from their just published paper. From the article:

These new images reveal that some regions of the asteroid have surface temperatures different from the average, indicating that Psyche’s composition is not uniform. The researchers also found that Psyche has a relatively high thermal inertia compared to other asteroids, yet it radiates approximately 60% less heat than would be expected for an object with such a high inertia. The researchers hypothesize that this is because the asteroid’s surface is at least 30% metal. However, the light reflecting off Psyche’s surface is unpolarized, which would not be the case for an object with a smooth or solid metallic surface. They therefore hypothesize that metallic grains are spread throughout its surface material, causing the light to scatter.

Though Psyche is large, 178 by 144 by 101 miles, it is not spherical like Ceres, the largest asteroid in the asteroid belt at 580 miles diameter. Thus, somewhere from the size of Psyche to the size of Ceres we move from an irregular asteroid body to a spherical planetary body, as it appears most planetary scientists define planets.

The probe Psyche is scheduled to launch in August ’22 to arrive at Psyche in ’26.

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Asteroid discovered with shortest orbit yet

8:55 am

Astroid's orbit
Click for full image.

Astronomers have discovered an asteroid that circles the Sun with the shortest orbit yet found, flying mostly inside the orbit of Mercury.

The illustration to the right shows the asteroids orbit, which is also tilted 32 degrees from the plane of the solar system.

The orbit of the approximately 1-kilometer-diameter asteroid takes it as close as 20 million kilometers (12 million miles or 0.13 au), from the Sun every 113 days. Asteroid 2021 PH27, revealed in images acquired during twilight, also has the smallest mean distance (semi-major axis) of any known asteroid in our Solar System — only Mercury has a shorter period and smaller semi-major axis. The asteroid is so close to the Sun’s massive gravitational field, it experiences the largest general relativistic effects of any known Solar System object.

Relatively few asteroids have been found with orbits shorter than Earth’s, because to find them astronomers have to turn their telescopes sunward, where viewing is limited to the early evening or early morning. Few space-based telescopes in all wavelengths also don’t look this way much, because of the risk of damage from the intense sunlight.

It is thus unknown exactly how many asteroids exist with similar orbits. There may be many, with many having short eccentric orbits, similar to comets, that extend out to Earth’s orbit and thus pose a risk. Or there may be few, since such orbits so close to the Sun are likely to cause the asteroid’s break-up and destruction over time.

Knowing how many of course is important, in order to obtain a full census of those asteroids in the solar system that might hit the Earth. To get it will likely require placing a probe designed to look for them.

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Hawaiian TMT protesters found not guilty of obstructing the road they obstructed

9:05 am

The law for thee but not for me: An Hawaiian judge has ruled that the protesters of the Thirty Meter Telesecope (TMT) who had obstructed the access road to the top of Mauna Kea are not guilty of obstructing that road.

[I]n announcing her verdict, the judge noted that during the trial, officials testified that the access road was closed and there were no permits issued for oversized vehicles. “Evidence that Mauna Kea access road was closed or restricted to the public, coupled with no permits, equals no obstruction,” Laubach said. “There would be no unreasonable inconvenience or hazard.”

The state failed to meet its burden beyond a reasonable doubt, she said.

This ruling is a joke. The reason the officials closed the road was because the protesters were there. The officials did not want anyone hurt by the oversized trucks that had legal permission to drive through carrying TMT construction equipment.

Such a ruling however is not a surprise. From top to bottom Hawaii’s government in controlled by the Democratic Party. The judge almost certainly was a Democrat. The Democrats favor the bigoted anti-white and anti-technology agenda of the protesters, and have gone out of their way to help them in their protests.

In general, protesters for Democratic Party causes can loot, burn, kill, obstruct traffic, and do all sorts of violent things — including physically attacking women and children in a park in Portland — and are either never arrested, quickly released on dropped charges, or found innocent.

Be a conservative and spend a dozen minutes inside the Capitol Building taking a few selfies, however, and you will find yourself imprisoned for months, with no charges brought and no sign they ever will be brought. You are guilty, and you will be punished. How dare you do anything that opposes the Democratic Party and its storm trooper thugs?

TMT is never going to be built in Hawaii. In fact, I am beginning to doubt it will ever be built anywhere. Considering the increasing difficulty that ground-based astronomy is going to have dealing with the many satellite constellations now being launched, it is very possible the support for the telescope will begin to dry up. And maybe this failure will be a signal to astronomers that they should finally begin spending their money on space-based optical telescopes.

Meanwhile, Hawaii has become a place hostile to science, to new knowledge, and even to tourism. The dark age there has come quite quickly.

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Scientists: Betelgeuse dimmed because of giant dark spot on surface

12:00 pm

The uncertainty of science: A new study by scientists in China now proposes that the dimming of the red giant star Betelgeuse in 2019-2020 was because of a giant dark and cold spot on its surface.

When Betelgeuse was at its dimmest on Jan. 31, 2020, its effective temperature — meaning, the temperature calculated from its emitted radiation — was measured at 3,476 degrees Kelvin (about 5,800 degrees Fahrenheit or 3,200 degrees Celsius.)

But once the star was back to a normal luminosity, measurements indicated an almost 5% temperature rise to 3,646 Kelvin (roughly 6,100 F or 3,370 degrees C.)

…[T]he astronomers … concluded it is unlikely the entire surface cooled temporarily by that amount. Rather, it must have been a sunspot — or rather, a “star spot” — blocking some of Betelgeuse’s radiation from escaping, they said.

This new hypothesis aligns partly with others that say it was a combination of a dark spot and intevening dust that caused the dimming.

None of these hypotheses however “solve” the mystery. Too little concrete information exists at present to do that.

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