Tag: astronomy

Hubble resumes full science operations

2:35 pm

Engineers have now successfully reactivated the Hubble Space Telescope’s second spectrograph, so that the telescope is now fully operational for the first time since it went into safe mode on October 25th.

NASA’s Hubble Space Telescope team recovered the Space Telescope Imaging Spectrograph on Monday, Dec. 6, and is now operating with all four active instruments collecting science. The team has still not detected any further synchronization message issues since monitoring began Nov. 1.

The team will continue work on developing and testing changes to instrument software that would allow them to conduct science operations even if they encounter several lost synchronization messages in the future. The first of these changes is scheduled to be installed on the Cosmic Origins Spectrograph in mid-December. The other instruments will receive similar updates in the coming months.

Essentially, they are modifying the telescope’s software so that it will not shut down should it “encounter several lost synchronization messages.” As the engineers have never fully explained this issue, I suspect this is a work-around to ignore an issue that in the past they would have taken more seriously. Now they are doing a cost-benefit analysis, and have decided that ignoring some of these messages is better than fixing them. It might even be impossible to do so.

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Astronomers discover galaxy with no dark matter

3:46 pm

The uncertainty of science: Astronomers have detected a galaxy about 250 million light years away that shows no evidence of any dark matter, a phenomenon that defies the accepted theories about dark matter.

The galaxy in question, AGC 114905, is about 250 million light-years away. It is classified as an ultra-diffuse dwarf galaxy, with the name ‘dwarf galaxy’ referring to its luminosity and not to its size. The galaxy is about the size of our own Milky Way but contains a thousand times fewer stars. The prevailing idea is that all galaxies, and certainly ultra-diffuse dwarf galaxies, can only exist if they are held together by dark matter.
Galaxy AGC 114905

The researchers collected data on the rotation of gas in AGC 114905 for 40 hours between July and October 2020 using the VLA telescope. Subsequently, they made a graph showing the distance of the gas from the center of the galaxy on the x-axis and the rotation speed of the gas on the y-axis. This is a standard way to reveal the presence of dark matter. The graph shows that the motions of the gas in AGC 114905 can be completely explained by just normal matter.

“This is, of course, what we thought and hoped for because it confirms our previous measurements,” says Pavel Mancera Piña. “But now the problem remains that the theory predicts that there must be dark matter in AGC 114905, but our observations say there isn’t. In fact, the difference between theory and observation is only getting bigger.”

The evidence for dark matter in almost all galaxies is the motion of gas and stars in the outer perimeter. Routinely they move faster than expected based merely on visible ordinary matter. To account for the faster speed, astronomers beginning in the late 1950s invented dark matter, an invisible material with a mass sufficient to increase the speeds of objects and gas in the outer regions of galaxies.

That increasingly astronomers are finding galaxies with no evidence of dark matter, based on rotation speeds, only makes this mystery all the more baffling.

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Engineers recover a third Hubble instrument

2:39 pm

Engineers have now reactivated a third instrument on the Hubble Space Telescope, bringing the telescope very close to full operations again with only one instrument, a spectrograph, still in safe mode.

The Hubble Space Telescope team recovered the Cosmic Origins Spectrograph instrument on Sunday, Nov. 28, moving the telescope further toward full science operations. Three of Hubble’s four active instruments are now collecting science data once again.

The team also continued work on developing and testing changes to instrument software that would allow them to conduct science operations even if they encounter several lost synchronization messages in the future. Those changes would first be installed on the Cosmic Origins Spectrograph once they’re completed and tested within a few weeks. Hubble’s other instruments would also receive similar changes. The team has not detected further synchronization message issues since monitoring began Nov. 1.

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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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