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A major lunar standstill is about to occur. The phenomenon happens every 18.6 years when the moon rises and sets at its most extreme points on the horizon, while also climbing to its highest and lowest point in the sky.

Studying the history of science shows how often serendipity plays a role in some of the most important discoveries. Sometimes, the stories are apocryphal, like Newton getting hit on the head with an apple. But sometimes, there’s an element of truth to them. That was the case for a new discovery of the oldest pair of merging quasars ever discovered – and it all started with a pair of red blots on a picture.

Those red blots were on a very particular picture – one taken by the Hyper Subprime-Cam on the Subaru telescope in Manuakea, Hawai’i. Yoshiki Matsuoka of Ehime University in Japan, who was manually reviewing the picture with colleagues, noticed two faint red splotches. Unlike an automated algorithm, which might have overlooked them, he was interested in what might have caused them and decided to look closer.

To do so, he recruited another instrument on the Subaru telescope, known as the Faint Object Camera and Spectrograph, and the Gemini Near-Infrared Spectrograph on the neighboring Gemini North telescope. After combing through this more targeted data, Dr. Matsuoka and his colleagues found something no one had seen before—a pair of merging quasars from less than a billion years after the universe was created.

Fraser explains what a quasar is, and why they’re so important.

Quasar mergers were theorized to happen all the time during that period, but despite having found 300 separate quasars around the same time frame, astronomers had yet to find any pairs. This was important because that time period, known as the Epoch of Reionization, was key in creating the structure of the modern-day universe.

During the Epoch of Reionization, energy, potentially from merging quasars, stripped the free-floating hydrogen abundant in the early universe of its electrons in a process called ionization. Around 1 billion years after the Big Bang and the theoretical end of the Epoch of Reionization, the structure of the modern universe was largely settled, and it had officially moved out of the period known as the “cosmic dark ages.” 

Understanding this period is critical for theorizing how the universe formed. Astronomers had long thought that merging quasars would have been common in the period, as supermassive black holes were relatively close, and structures were still working themselves out. So, the lack of them in experimental data was concerning. 

Quasars aren’t only ancient history – could our own supermassive black hole at the center of the Milky Way become one?

Enter the pair found by Dr. Matsuoka and his colleagues. They appear about 900 million years after the Big Bang, still well within the Epoch of Reionization. However, collecting data on them wasn’t easy, as old objects suffer from contamination in their signals, such as gravitational lensing and stars in the foreground. The researchers eventually found that some of the optical light wasn’t directly coming from the quasars but rather the formation of stars around them.

However, the quasars were massive behemoths, weighing over 100 million times more than our Sun. They also had a bridge of gas connecting them, implying that the two galaxies they formed the core of were undergoing a massive merger, which we will now get to observe as it happens. 

That merger is going to take millions, if not billions, of years, though, so it might be some time before we see the full effect. But in the meantime, cosmologists can start studying this quasar pair in earnest to see what other details can be gleaned about the Epoch of Reionization or the formation of the universe more generally. And it will all happen because someone noticed some red blots on a picture and decided to investigate it further.

Learn More:
NOIRLab – International Gemini Observatory and Subaru Combine Forces to Discover First Ever Pair of Merging Quasars at Cosmic Dawn
Matsuoka et al – Discovery of Merging Twin Quasars at z = 6.05
UT – Hubble Sees Two Quasars Side by Side in the Early Universe
UT – The James Webb Is Getting Closer to Finding What Ionized the Universe

Lead Image:
Illustration of merging quasars
Credit – NOIRLab/NSF/AURA/M. Garlick

The post The Earliest Merging Quasars Ever Seen appeared first on Universe Today.

The face of summer is transforming, as people today face more frequent, longer-lasting and hotter heat waves than they did several decades ago

Video: 00:36:48

ESA Director General Josef Aschbacher and ESA Council Chair Renato Krpoun brief journalists on decisions taken at the ESA Council meeting held in Paris on 18 and 19 June 2024.

Astronomers have, for the first time, spotted a black hole in a nearby galaxy waking up from a deep slumber.

The simplicity of the recycling symbol belies its complicated role in corporate America’s quest to sell ever more plastic

Scientists found the building bricks for moon bases in the toy store, and you can see them there, too. ESA researchers discovered more than inspiration from Lego while working on Artemis structures.

Programmable liquids could aid robot grippers, shock absorption, acoustics, and more

Radiation surveys suggest that it is now safe to grow food on farmland that has been unused since the Chernobyl nuclear disaster, but changing its status would face local opposition in Ukraine

Radiation surveys suggest that it is now safe to grow food on farmland that has been unused since the Chernobyl nuclear disaster, but changing its status would face local opposition in Ukraine

Just like with other tools, the more a coronagraph ages, the less reliable it gets. So, next month, NOAA's GOES-U will take to space a brand-new coronagraph which will provide clearer images of the sun's activity.

Gray whales in a small group that sticks close to the shores of the Pacific Northwest appear to be shrinking—and shockingly quickly

Maximize your planetary pleasure and get re-acquainted with Earth's siblings during the June 29th dawn planet parade.

The post See the Real Planet Parade appeared first on Sky & Telescope.

Negotiations over a global pandemic treaty broke down at WHO this year. The legacy of the world's unreadiness for COVID means that it is essential to adopt the accord in 2025

Nature still outdoes the machine, says a photographer whose real image won an AI photography competition

China has selected 10 new astronauts for training as part of its goal to put a crew on the moon by 2030, the country's human spaceflight agency announced last week.

A nuclear explosion in space would cause stunning auroras—and wreak havoc on satellites and space stations.

SpaceX launched 20 of its Starlink satellites from California on Tuesday night (June 18), ending a 10-day spaceflight drought for the company.

The Hubble Space Telescope has experienced ongoing problems with one of its three remaining gyroscopes, so NASA has decided to shift the telescope into single gyro mode. While the venerable space telescope has now returned to daily science operations, single gyro mode means Hubble will only use one gyro to maintain a lock on its target. This will slow its slew time and decrease some of its scientific output. But this plan increases the overall lifetime of the 34-year-old telescope, keeping one gyro in reserve. NASA is also troubleshooting the malfunctioning gyro, hoping to return it online.

Last week, NASA said that the telescope and its instruments are stable and functioning normally.

Gyroscopes help the telescope orient itself in space, keeping it stable to precisely point at astronomical targets in the distant Universe. Hubble went into safe mode back in November 2023, and then again in April and May 2024 due to the ongoing issue, where the one gyro had been increasingly returning faulty readings.

The end of a Hubble gyro reveals the hair-thin wires known as flex leads. They carry data and electricity inside the gyro. Credit: NASA

Going in to safe mode suspends science operations, and in the meantime, engineers tried to troubleshoot to figure out why the gyro experiencing the fault-producing issues and doing work-arounds to get the telescope up and running again. The most recent last safe-mode event in May led the Hubble team to transition from a three-gyro operating mode to observing with only one gyro. This enables more consistent science observations while keeping the other operational gyro available for future use.

Launched in 1990, Hubble has more than doubled its expected design lifetime, providing stunning images and scientific discoveries that have changed our understanding of the Universe and re-written astronomy textbooks.  

During its 34-year history, Hubble has had eight out of 22 gyros fail due to a corroded flex lead, which are thin (less than the width of a human hair) metal wires, that carry power in, and data out, of the gyro.  The flex leads pass through a thick fluid inside the gyro and over time, the flex leads begin to corrode and can physically bend or break.

With his feet firmly anchored on the shuttle’s robotic arm, astronaut Mike Good maneuvers to retrieve the tool caddy required to repair the Space Telescope Imaging Spectrograph during the final Hubble servicing mission in May 2009. Periodic upgrades have kept the telescope equipped with state-of-the-art instruments, which have given astronomers increasingly better views of the cosmos. Credits: NASA

Thankfully, for the first 18 years of Hubble’s life in space, the telescope had the advantage of being able to be serviced and upgraded by space shuttle astronauts. For example, in 1999, four out of six gyros had failed, with the last one failing about a month before a servicing mission was scheduled to replace them (and do other upgrades to the telescope). This meant Hubble sat in safe mode waiting for the space shuttle and astronauts to arrive.

When the final planned Hubble servicing mission was (temporarily) canceled following the space shuttle Columbia disaster, engineers developed and inaugurated a two-gyro mode to prolong Hubble’s life. The mission was reinstated after outcry from scientists and the public, and so NASA figured out a way to mitigate the risks of flying the space shuttle. Servicing Mission 4 replaced all six gyros one last time in 2009, but it has been running on three since 2018. The three gyros all quit working due to flex lead failures. The retirement of the space shuttle means Hubble has now been operating for 15 years without servicing.

The Hubble Rate Gyro Assembly contains a gyroscope and all of its associated electronics. The gyroscopes are part of Hubble’s pointing system. They provide a frame of reference for Hubble to determine where it is pointing and how that pointing changes as the telescope moves across the sky. They report any small movements of the spacecraft to Hubble’s pointing and Control System. The computer then commands the spinning reaction wheels to keep the spacecraft stable or moving at the desired rate. Credit: NASA

However, during the time it was thought no future servicing mission would happen, the team also devised a one-gyro mode, which will further extend Hubble’s life.

“We knew gyros would be a limiting factor so we started to working on a reduced gyro mode to extend their life,” the director of the Space Telescope Science Institute Ken Sembach told me back in 2015 for my book, “Incredible Stories From Space.” “As it turned out, we did need that reduced gyro mode, and now they aren’t [as big of a] limiting factor for Hubble because we now know how to use the gyro resources in a new way. That added a longer life to the mission we didn’t think we would have.”

While engineers say the difference between two-gyro mode and one gyro-mode is negligible, one-gyro mode provides the option to have one of the remaining gyros placed in reserve.

NASA says that although one-gyro mode is an excellent way to keep Hubble science operations going, it does have limitations, which include a small decrease in efficiency (roughly 12 percent) due to the added time required to slew and lock the telescope onto a science target. One gyro mode also means it takes additional time for the telescope’s fine guidance sensors to search for the guide stars. Additionally, in one-gyro mode Hubble has some restrictions on the science it can do. For example, Hubble cannot track moving objects that are closer to Earth than the orbit of Mars. Without the full complement of gyros, the motion of these objects are too fast for the telescope to track. Additionally, the reduced area of sky that Hubble can point to at any given time also reduces its flexibility to see transient events or targets of opportunity like an exploding star or an impact on Jupiter. NASA says that when combined, “these factors may yield a decrease in productivity of roughly 20 to 25 percent from the typical observing program conducted in the past using all three gyros.”

Read more about the “new normal” for Hubble’s one-gyro mode at this NASA webpage.

The post Hubble's Back, but Only Using One Gyro appeared first on Universe Today.

Slovenia signed the Accession Agreement to the ESA Convention on 18 June 2024. Upon ratification, Slovenia will become the 23rd ESA Member State.