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By NASA
With the historic first international space docking mission only six months away, preparations on the ground for the Apollo-Soyuz Test Project (ASTP) intensified. At NASA’s Kennedy Space Center (KSC) in Florida, workers in the Vehicle Assembly Building (VAB) stacked the rocket for the mission, the final Saturn rocket assembled for flight. In the nearby Manned Spacecraft Operations Building (MSOB), the Apollo prime crew of Commander Thomas Stafford, Command Module Pilot Vance Brand, and Docking Module Pilot Donald “Deke” Slayton, and their backups Alan Bean, Ronald Evans, and Jack Lousma conducted vacuum chamber tests of the Command Module (CM), the final Apollo spacecraft prepared for flight.
Inside the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center in Florida, workers attach fins to the Saturn IB’s first stage. In the VAB, workers secure the first stage of the Saturn IB rocket onto the milk stool, perched on Mobile Launcher-1. Workers lift the second stage of the Saturn IB rocket prior to mating with the first stage. Workers lower a boilerplate Apollo spacecraft onto the Saturn IB rocket. The Saturn IB rocket, serial number SA-210, used for ASTP had a lengthy history. Contractors originally built its two stages in 1967, at a time when NASA planned many more Saturn IB flights to test Apollo spacecraft components in Earth orbit in preparation for the Moon landing. By 1968, however, after four uncrewed Saturn IB launches, only one launched a crew, Apollo 7. Four more Saturn IBs remained on reserve to launch crews as part of the Apollo Applications Program, renamed Skylab in 1970. Without an immediate mission, the two stages of SA-210 entered long-term storage in 1967. Workers later modified and refurbished the stages for ASTP before shipping them to KSC. The first stage arrived in April 1974 and the second stage in November 1972.
On Jan. 13, 1975, inside the cavernous VAB, workers stacked the Saturn IB rocket’s first stage onto Mobile Launcher-1 (ML-1), modified from its use to launch Saturn V rockets during the Apollo program with the addition of the milk stool pedestal. The milk stool, a 128-foot tall platform, allowed the Saturn IB to use the same Launch Umbilical Tower as the much larger Saturn V rocket at Launch Complex 39. The next day, workers lowered the second stage onto the first, followed by the Instrument Unit two days later. Finally, on Jan. 17 workers topped off the rocket with a boilerplate Apollo spacecraft while engineers continued testing the flight article in the MSOB.
The ASTP Apollo Command and Service Modules arrive at NASA’s Kennedy Space Center (KSC) in Florida. The ASTP Command Module arrives in KSC’s Manned Spacecraft Operations Building. The Command and Service Modules – CSM-111 – arrived at KSC from the Rockwell International plant in Downey, California, on Sept. 8, 1974, by C-5A Galaxy cargo plane. Rockwell had finished building the spacecraft in March 1970 and placed it in storage until July 1972. Modifications for ASTP took place between August 1972 and August 1974, following which Rockwell shipped the spacecraft to KSC. The sign on the shipping container bore the legend “From A to Soyuz – Apollo/Soyuz – Last and the Best.” Workers at KSC towed the modules to the MSOB for inspection and checkout, joined the two modules, and placed the combined spacecraft into a vacuum chamber.
The prime Apollo crew of Thomas Stafford, left, Vance Brand, and Donald “Deke” Slayton suit up in preparation for an altitude chamber test in the Command Module (CM). The astronauts inside the CM in the altitude chamber. In the MSOB, the prime and backup ASTP crews conducted tests of their spacecraft in an altitude chamber. After both crews completed simulated runs in December 1974, the prime crew of Stafford, Brand, and Slayton suited up, entered the CM inside the chamber, closed the hatch, and conducted an actual test on Jan. 14, with the chamber simulating altitudes of up to 220,000 feet. Two days later, the backup crew of Bean, Evans, and Lousma completed a similar test.
he backup Apollo crew of Alan Bean, left, Ronald Evans, and Jack Lousma suit up in preparation for an altitude chamber test in the Command Module (CM). Workers assist backup crewmember Lousma into the CM. To solve the problem of the Apollo and Soyuz spacecraft operating at different atmospheric pressures and compositions and using incompatible docking mechanisms, engineers designed a Docking Module (DM) that acted as both an airlock and a transfer tunnel and a Docking System (DS) that allowed the two nations’ spacecraft to physically join in space. NASA contracted with Rockwell International to build the DM. Engineers equipped one end of the DM with the standard Apollo probe-and-drogue docking mechanism and the other end with the androgynous system that linked up with its opposite half installed on the modified Soyuz spacecraft. During launch, the DM rested inside the Spacecraft Lunar Module (LM) Adaptor (SLA) atop the rocket’s upper stage, much like the LM during Apollo flights. Once in orbit, the astronauts separated the CSM from the upper stage, turned the spacecraft around, docked with the DM and pulled it free.
Workers lower the DM into Chamber B in the Space Environment Simulation Laboratory at NASA’s Johnson Space Center in Houston. Workers lower the DM into Chamber B in the Space Environment Simulation Laboratory at NASA’s Johnson Space Center in Houston. After extensive vacuum testing in Chamber B of the Space Environment Simulation Laboratory at NASA’s Johnson Space Center in Houston, the flight DM arrived at KSC on Oct. 29, 1974, and workers prepared it for more testing in a vacuum chamber in the MSOB. The flight DS arrived at KSC on Jan. 3, 1975, and two weeks later workers installed it on the DM. On Jan. 27, engineers lowered the DM onto the CM in the altitude chamber to conduct a mechanical docking test. Engineers conducted 10 days of joint tests of television and audio equipment to ensure systems compatibility.
Workers conduct a docking test of the Docking Module with the Command Module at NASA’s Kennedy Space Center in Florida. NASA support astronaut Robert Overmyer, right, works with engineers during compatibility testing. To be continued…
Major events around the world in January 1975:
January 5 – Musical The Wiz opens on Broadway, runs for 1,672 performances.
January 6 – The game show Wheel of Fortune debuts on NBC.
January 8 – Ella Grasso of Connecticut becomes the first elected female governor in the U.S.
January 11 – The S-II second stage of the Saturn V rocket that launched Skylab reenters the Earth’s atmosphere over the Indian Ocean.
January 12 – The Pittsburg Steelers beat the Minnesota Vikings in Super Bowl IX, played in Tulane Stadium in New Orleans.
January 15 – Space Mountain opens at Disney World in Orlando.
January 18 – The Jeffersons premieres on CBS.
January 22 – Launch of the Landsat-2 Earth resources monitoring satellite.
January 30 – Ernő Rubik applies for a patent in Hungary for his Magic Cube, later known as Rubik’s Cube.
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By NASA
Hubble Space TelescopeHubble Home OverviewAbout Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & BenefitsHubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts ScienceHubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky ObservatoryHubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb TeamHubble Team Career Aspirations Hubble Astronauts NewsHubble News Hubble News Archive Social Media Media Resources MultimediaMultimedia Images Videos Sonifications Podcasts e-Books Online Activities Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More35th Anniversary 7 Min Read NASA Celebrates Edwin Hubble’s Discovery of a New Universe
The Cepheid variable star, called V1, in the neighboring Andromeda galaxy. Credits: NASA, ESA, Hubble Heritage Team (STScI/AURA); Acknowledgement: R. Gendler For humans, the most important star in the universe is our Sun. The second-most important star is nestled inside the Andromeda galaxy. Don’t go looking for it — the flickering star is 2.2 million light-years away, and is 1/100,000th the brightness of the faintest star visible to the human eye.
Yet, a century ago, its discovery by Edwin Hubble, then an astronomer at Carnegie Observatories, opened humanity’s eyes as to how large the universe really is, and revealed that our Milky Way galaxy is just one of hundreds of billions of galaxies in the universe ushered in the coming-of-age for humans as a curious species that could scientifically ponder our own creation through the message of starlight. Carnegie Science and NASA are celebrating this centennial at the 245th meeting of the American Astronomical Society in Washington, D.C.
The seemingly inauspicious star, simply named V1, flung open a Pandora’s box full of mysteries about time and space that are still challenging astronomers today. Using the largest telescope in the world at that time, the Carnegie-funded 100-inch Hooker Telescope at Mount Wilson Observatory in California, Hubble discovered the demure star in 1923. This rare type of pulsating star, called a Cepheid variable, is used as milepost markers for distant celestial objects. There are no tape-measures in space, but by the early 20th century Henrietta Swan Leavitt had discovered that the pulsation period of Cepheid variables is directly tied to their luminosity.
Many astronomers long believed that the edge of the Milky Way marked the edge of the entire universe. But Hubble determined that V1, located inside the Andromeda “nebula,” was at a distance that far exceeded anything in our own Milky Way galaxy. This led Hubble to the jaw-dropping realization that the universe extends far beyond our own galaxy.
In fact Hubble had suspected there was a larger universe out there, but here was the proof in the pudding. He was so amazed he scribbled an exclamation mark on the photographic plate of Andromeda that pinpointed the variable star.
In commemoration of Edwin Hubble’s discovery of a Cepheid variable class star, called V1, in the neighboring Andromeda galaxy 100 years ago, astronomers partnered with the American Association of Variable Star Observers (AAVSO) to study the star. AAVSO observers followed V1 for six months, producing a plot, or light curve, of the rhythmic rise and fall of the star’s light. Based on this data, the Hubble Space Telescope was scheduled to capture the star at its dimmest and brightest light. Edwin Hubble’s observations of V1 became the critical first step in uncovering a larger, grander universe than some astronomers imagined at the time. Once dismissed as a nearby “spiral nebula” measurements of Andromeda with its embedded Cepheid star served as a stellar milepost marker. It definitively showed that Andromeda was far outside of our Milky Way. Edwin Hubble went on to measure the distances to many galaxies beyond the Milky Way by finding Cepheid variables within those levels. The velocities of those galaxies, in turn, allowed him to determine that the universe is expanding.NASA, ESA, Hubble Heritage Team (STScI/AURA); Acknowledgment: R. Gendler As a result, the science of cosmology exploded almost overnight. Hubble’s contemporary, the distinguished Harvard astronomer Harlow Shapley, upon Hubble notifying him of the discovery, was devastated. “Here is the letter that destroyed my universe,” he lamented to fellow astronomer Cecilia Payne-Gaposchkin, who was in his office when he opened Hubble’s message.
Just three years earlier, Shapley had presented his observational interpretation of a much smaller universe in a debate one evening at the Smithsonian Museum of Natural History in Washington. He maintained that the Milky Way galaxy was so huge, it must encompass the entirety of the universe. Shapley insisted that the mysteriously fuzzy “spiral nebulae,” such as Andromeda, were simply stars forming on the periphery of our Milky Way, and inconsequential.
Little could Hubble have imagined that 70 years later, an extraordinary telescope named after him, lofted hundreds of miles above the Earth, would continue his legacy. The marvelous telescope made “Hubble” a household word, synonymous with wonderous astronomy.
Today, NASA’s Hubble Space Telescope pushes the frontiers of knowledge over 10 times farther than Edwin Hubble could ever see. The space telescope has lifted the curtain on a compulsive universe full of active stars, colliding galaxies, and runaway black holes, among the celestial fireworks of the interplay between matter and energy.
Edwin Hubble was the first astronomer to take the initial steps that would ultimately lead to the Hubble Space Telescope, revealing a seemingly infinite ocean of galaxies. He thought that, despite their abundance, galaxies came in just a few specific shapes: pinwheel spirals, football-shaped ellipticals, and oddball irregular galaxies. He thought these might be clues to galaxy evolution – but the answer had to wait for the Hubble Space Telescope’s legendary Hubble Deep Field in 1994.
The most impactful finding that Edwin Hubble’s analysis showed was that the farther the galaxy is, the faster it appears to be receding from Earth. The universe looked like it was expanding like a balloon. This was based on Hubble tying galaxy distances to the reddening of light — the redshift – that proportionally increased the father away the galaxies are.
The redshift data were first collected by Lowell Observatory astronomer Vesto Slipher, who spectroscopically studied the “spiral nebulae” a decade before Hubble. Slipher did not know they were extragalactic, but Hubble made the connection. Slipher first interpreted his redshift data an example of the Doppler effect. This phenomenon is caused by light being stretched to longer, redder wavelengths if a source is moving away from us. To Slipher, it was curious that all the spiral nebulae appeared to be moving away from Earth.
Two years prior to Hubble publishing his findings, the Belgian physicist and Jesuit priest Georges Lemaître analyzed the Hubble and Slifer observations and first came to the conclusion of an expanding universe. This proportionality between galaxies’ distances and redshifts is today termed Hubble–Lemaître’s law.
Because the universe appeared to be uniformly expanding, Lemaître further realized that the expansion rate could be run back into time – like rewinding a movie – until the universe was unimaginably small, hot, and dense. It wasn’t until 1949 that the term “big bang” came into fashion.
This was a relief to Edwin Hubble’s contemporary, Albert Einstein, who deduced the universe could not remain stationary without imploding under gravity’s pull. The rate of cosmic expansion is now known as the Hubble Constant.
Ironically, Hubble himself never fully accepted the runaway universe as an interpretation of the redshift data. He suspected that some unknown physics phenomenon was giving the illusion that the galaxies were flying away from each other. He was partly right in that Einstein’s theory of special relativity explained redshift as an effect of time-dilation that is proportional to the stretching of expanding space. The galaxies only appear to be zooming through the universe. Space is expanding instead.
Compass and scale image titled “Cepheid Variable Star V1 in M31 HST WFC3/UVIS.” Four boxes each showing a bright white star in the center surrounded by other stars. Each box has a correlating date at the bottom: Dec. 17, 2020, Dec. 21, 2010, Dec. 30, 2019, and Jan. 26, 2011. The center star in the boxes appears brighter with each passing date.NASA, ESA, Hubble Heritage Project (STScI, AURA) After decades of precise measurements, the Hubble telescope came along to nail down the expansion rate precisely, giving the universe an age of 13.8 billion years. This required establishing the first rung of what astronomers call the “cosmic distance ladder” needed to build a yardstick to far-flung galaxies. They are cousins to V1, Cepheid variable stars that the Hubble telescope can detect out to over 100 times farther from Earth than the star Edwin Hubble first found.
Astrophysics was turned on its head again in 1998 when the Hubble telescope and other observatories discovered that the universe was expanding at an ever-faster rate, through a phenomenon dubbed “dark energy.” Einstein first toyed with this idea of a repulsive form of gravity in space, calling it the cosmological constant.
Even more mysteriously, the current expansion rate appears to be different than what modern cosmological models of the developing universe would predict, further confounding theoreticians. Today astronomers are wrestling with the idea that whatever is accelerating the universe may be changing over time. NASA’s Roman Space Telescope, with the ability to do large cosmic surveys, should lead to new insights into the behavior of dark matter and dark energy. Roman will likely measure the Hubble constant via lensed supernovae.
This grand century-long adventure, plumbing depths of the unknown, began with Hubble photographing a large smudge of light, the Andromeda galaxy, at the Mount Wilson Observatory high above Los Angeles.
In short, Edwin Hubble is the man who wiped away the ancient universe and discovered a new universe that would shrink humanity’s self-perception into being an insignificant speck in the cosmos.
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
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Edwin Hubble Hubble Views the Star That Changed the Universe The History of Hubble Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contact:
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Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Discovering a Runaway Universe
Our cosmos is growing, and that expansion rate is accelerating.
The History of Hubble
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By NASA
Astronomers have released a set of more than a million simulated images showcasing the cosmos as NASA’s upcoming Nancy Grace Roman Space Telescope will see it. This preview will help scientists explore a myriad of Roman’s science goals.
“We used a supercomputer to create a synthetic universe and simulated billions of years of evolution, tracing every photon’s path all the way from each cosmic object to Roman’s detectors,” said Michael Troxel, an associate professor of physics at Duke University in Durham, North Carolina, who led the simulation campaign. “This is the largest, deepest, most realistic synthetic survey of a mock universe available today.”
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This video begins with a tiny one-square-degree portion of the full OpenUniverse simulation area (about 70 square degrees, equivalent to an area of sky covered by more than 300 full moons). It spirals in toward a particularly galaxy-dense region, zooming by a factor of 75. This simulation showcases the cosmos as NASA’s Nancy Grace Roman Space Telescope could see it, allowing scientists to preview the next generation of cosmic discovery now. Roman’s real future surveys will enable a deep dive into the universe with highly resolved imaging, as demonstrated in this video. NASA’s Goddard Space Flight Center and M. Troxel The project, called OpenUniverse, relied on the now-retired Theta supercomputer at the DOE’s (Department of Energy’s) Argonne National Laboratory in Illinois. The supercomputer accomplished a process that would take over 6,000 years on a typical computer in just nine days.
In addition to Roman, the 400-terabyte dataset will also preview observations from the Vera C. Rubin Observatory, which is jointly funded by the National Science Foundation and the U.S. Department of Energy, and approximate simulations from ESA’s (the European Space Agency’s) Euclid mission, which has NASA contributions. The Roman data is available now here, and the Rubin and Euclid data will soon follow.
The team used the most sophisticated modeling of the universe’s underlying physics available and fed in information from existing galaxy catalogs and the performance of the telescopes’ instruments. The resulting simulated images span 70 square degrees, equivalent to an area of sky covered by more than 300 full moons. In addition to covering a broad area, it also covers a large span of time — more than 12 billion years.
Each tiny dot in the image at left is a galaxy simulated by the OpenUniverse campaign. The one-square-degree image offers a small window into the full simulation area, which is about 70 square degrees (equivalent to an area of sky covered by more than 300 full moons), while the inset at right is a close-up of an area 75 times smaller (1/600th the size of the full area). This simulation showcases the cosmos as NASA’s Nancy Grace Roman Space Telescope could see it. Roman will expand on the largest space-based galaxy survey like it – the Hubble Space Telescope’s COSMOS survey – which imaged two square degrees of sky over the course of 42 days. In only 250 days, Roman will view more than a thousand times more of the sky with the same resolution. The project’s immense space-time coverage shows scientists how the telescopes will help them explore some of the biggest cosmic mysteries. They will be able to study how dark energy (the mysterious force thought to be accelerating the universe’s expansion) and dark matter (invisible matter, seen only through its gravitational influence on regular matter) shape the cosmos and affect its fate. Scientists will get closer to understanding dark matter by studying its gravitational effects on visible matter. And by studying the simulation’s 100 million synthetic galaxies, they will see how galaxies and galaxy clusters evolved over eons.
Repeated mock observations of a particular slice of the universe enabled the team to stitch together movies that unveil exploding stars crackling across the synthetic cosmos like fireworks. These starbursts allow scientists to map the expansion of the simulated universe.
This simulation showcases the dynamic universe as NASA’s Nancy Grace Roman Space Telescope could see it over the course of its five-year primary mission. The video sparkles with synthetic supernovae from observations of the OpenUniverse simulated universe taken every five days (similar to the expected cadence of Roman’s High-Latitude Time-Domain Survey, which OpenUniverse simulates in its entirety). On top of the static sky of stars in the Milky Way and other galaxies, more than a million exploding stars flare into visibility and then slowly fade away. To highlight the dynamic physics happening and for visibility at this scale, the true brightness of each transient event has been magnified by a factor of 10,000 and no background light has been added to the simulated images. The video begins with Roman’s full field of view, which represents a single pointing of Roman’s camera, and then zooms into one square.NASA’s Goddard Space Flight Center and M. Troxel Scientists are now using OpenUniverse data as a testbed for creating an alert system to notify astronomers when Roman sees such phenomena. The system will flag these events and track the light they generate so astronomers can study them.
That’s critical because Roman will send back far too much data for scientists to comb through themselves. Teams are developing machine-learning algorithms to determine how best to filter through all the data to find and differentiate cosmic phenomena, like various types of exploding stars.
“Most of the difficulty is in figuring out whether what you saw was a special type of supernova that we can use to map how the universe is expanding, or something that is almost identical but useless for that goal,” said Alina Kiessling, a research scientist at NASA’s Jet Propulsion Laboratory (JPL) in Southern California and the principal investigator of OpenUniverse.
While Euclid is already actively scanning the cosmos, Rubin is set to begin operations late this year and Roman will launch by May 2027. Scientists can use the synthetic images to plan the upcoming telescopes’ observations and prepare to handle their data. This prep time is crucial because of the flood of data these telescopes will provide.
In terms of data volume, “Roman is going to blow away everything that’s been done from space in infrared and optical wavelengths before,” Troxel said. “For one of Roman’s surveys, it will take less than a year to do observations that would take the Hubble or James Webb space telescopes around a thousand years. The sheer number of objects Roman will sharply image will be transformative.”
This synthetic OpenUniverse animation shows the type of science that astronomers will be able to do with future Roman deep-field observations. The gravity of intervening galaxy clusters and dark matter can lens the light from farther objects, warping their appearance as shown in the animation. By studying the distorted light, astronomers can study elusive dark matter, which can only be measured indirectly through its gravitational effects on visible matter. As a bonus, this lensing also makes it easier to see the most distant galaxies whose light the dark matter magnifies. Caltech-IPAC/R. Hurt “We can expect an incredible array of exciting, potentially Nobel Prize-winning science to stem from Roman’s observations,” Kiessling said. “The mission will do things like unveil how the universe expanded over time, make 3D maps of galaxies and galaxy clusters, reveal new details about star formation and evolution — all things we simulated. So now we get to practice on the synthetic data so we can get right to the science when real observations begin.”
Astronomers will continue using the simulations after Roman launches for a cosmic game of spot the differences. Comparing real observations with synthetic ones will help scientists see how accurately their simulation predicts reality. Any discrepancies could hint at different physics at play in the universe than expected.
“If we see something that doesn’t quite agree with the standard model of cosmology, it will be extremely important to confirm that we’re really seeing new physics and not just misunderstanding something in the data,” said Katrin Heitmann, a cosmologist and deputy director of Argonne’s High Energy Physics division who managed the project’s supercomputer time. “Simulations are super useful for figuring that out.”
OpenUniverse, along with other simulation tools being developed by Roman’s Science Operations and Science Support centers, will prepare astronomers for the large datasets expected from Roman. The project brings together dozens of experts from NASA’s JPL, DOE’s Argonne, IPAC, and several U.S. universities to coordinate with the Roman Project Infrastructure Teams, SLAC, and the Rubin LSST DESC (Legacy Survey of Space and Time Dark Energy Science Collaboration). The Theta supercomputer was operated by the Argonne Leadership Computing Facility, a DOE Office of Science user facility.
The Nancy Grace Roman Space Telescope is managed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with participation by NASA’s Jet Propulsion Laboratory and Caltech/IPAC in Southern California, the Space Telescope Science Institute in Baltimore, and a science team comprising scientists from various research institutions. The primary industrial partners are BAE Systems, Inc in Boulder, Colorado; L3Harris Technologies in Rochester, New York; and Teledyne Scientific & Imaging in Thousand Oaks, California.
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By Ashley Balzer
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Claire Andreoli
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Jan 14, 2025 EditorAshley BalzerContactAshley Balzerashley.m.balzer@nasa.govLocationGoddard Space Flight Center Related Terms
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Article 3 years ago View the full article
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By NASA
International teams of astronomers monitoring a supermassive black hole in the heart of a distant galaxy have detected features never seen before using data from NASA missions and other facilities. The features include the launch of a plasma jet moving at nearly one-third the speed of light and unusual, rapid X-ray fluctuations likely arising from near the very edge of the black hole.
Radio images of 1ES 1927+654 reveal emerging structures that appear to be jets of plasma erupting from both sides of the galaxy’s central black hole following a strong radio flare. The first image, taken in June 2023, shows no sign of the jet, possibly because hot gas screened it from view. Then, starting in February 2024, the features emerge and expand away from the galaxy’s center, covering a total distance of about half a light-year as measured from the center of each structure. NSF/AUI/NSF NRAO/Meyer at al. 2025 The source is 1ES 1927+654, a galaxy located about 270 million light-years away in the constellation Draco. It harbors a central black hole with a mass equivalent to about 1.4 million Suns.
“In 2018, the black hole began changing its properties right before our eyes, with a major optical, ultraviolet, and X-ray outburst,” said Eileen Meyer, an associate professor at UMBC (University of Maryland Baltimore County). “Many teams have been keeping a close eye on it ever since.”
She presented her team’s findings at the 245th meeting of the American Astronomical Society in National Harbor, Maryland. A paper led by Meyer describing the radio results was published Jan. 13 in The Astrophysical Journal Letters.
After the outburst, the black hole appeared to return to a quiet state, with a lull in activity for nearly a year. But by April 2023, a team led by Sibasish Laha at UMBC and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, had noted a steady, months-long increase in low-energy X-rays in measurements by NASA’s Neil Gehrels Swift Observatory and NICER (Neutron star Interior Composition Explorer) telescope on the International Space Station. This monitoring program, which also includes observations from NASA’s NuSTAR (Nuclear Spectroscopic Telescope Array) and ESA’s (European Space Agency) XMM-Newton mission, continues.
The increase in X-rays triggered the UMBC team to make new radio observations, which indicated a strong and highly unusual radio flare was underway. The scientists then began intensive observations using the NRAO’s (National Radio Astronomy Observatory) VLBA (Very Long Baseline Array) and other facilities. The VLBA, a network of radio telescopes spread across the U.S., combines signals from individual dishes to create what amounts to a powerful, high-resolution radio camera. This allows the VLBA to detect features less than a light-year across at 1ES 1927+654’s distance.
Active galaxy 1ES 1927+654, circled, has exhibited extraordinary changes since 2018, when a major outburst occurred in visible, ultraviolet, and X-ray light. The galaxy harbors a central black hole weighing about 1.4 million solar masses and is located 270 million light-years away. Pan-STARRS Radio data from February, April, and May 2024 reveals what appear to be jets of ionized gas, or plasma, extending from either side of the black hole, with a total size of about half a light-year. Astronomers have long puzzled over why only a fraction of monster black holes produce powerful plasma jets, and these observations may provide critical clues.
“The launch of a black hole jet has never been observed before in real time,” Meyer noted. “We think the outflow began earlier, when the X-rays increased prior to the radio flare, and the jet was screened from our view by hot gas until it broke out early last year.”
A paper exploring that possibility, led by Laha, is under review at The Astrophysical Journal. Both Meyer and Megan Masterson, a doctoral candidate at the Massachusetts Institute of Technology in Cambridge who also presented at the meeting, are co-authors.
Using XMM-Newton observations, Masterson found that the black hole exhibited extremely rapid X-ray variations between July 2022 and March 2024. During this period, the X-ray brightness repeatedly rose and fell by 10% every few minutes. Such changes, called millihertz quasiperiodic oscillations, are difficult to detect around supermassive black holes and have been observed in only a handful of systems to date.
“One way to produce these oscillations is with an object orbiting within the black hole’s accretion disk. In this scenario, each rise and fall of the X-rays represents one orbital cycle,” Masterson said.
If the fluctuations were caused by an orbiting mass, then the period would shorten as the object fell ever closer to the black hole’s event horizon, the point of no return. Orbiting masses generate ripples in space-time called gravitational waves. These waves drain away orbital energy, bringing the object closer to the black hole, increasing its speed, and shortening its orbital period.
Over two years, the fluctuation period dropped from 18 minutes to just 7 — the first-ever measurement of its kind around a supermassive black hole. If this represented an orbiting object, it was now moving at half the speed of light. Then something unexpected happened — the fluctuation period stabilized.
In this artist’s concept, matter is stripped from a white dwarf (sphere at lower right) orbiting within the innermost accretion disk surrounding 1ES 1927+654’s supermassive black hole. Astronomers developed this scenario to explain the evolution of rapid X-ray oscillations detected by ESA’s (European Space Agency) XMM-Newton satellite. ESA’s LISA (Laser Interferometer Space Antenna) mission, due to launch in the next decade, should be able to confirm the presence of an orbiting white dwarf by detecting the gravitational waves it produces. NASA/Aurore Simonnet, Sonoma State University “We were shocked by this at first,” Masterson explained. “But we realized that as the object moved closer to the black hole, its strong gravitational pull could begin to strip matter from the companion. This mass loss could offset the energy removed by gravitational waves, halting the companion’s inward motion.”
So what could this companion be? A small black hole would plunge straight in, and a normal star would quickly be torn apart by the tidal forces near the monster black hole. But the team found that a low-mass white dwarf — a stellar remnant about as large as Earth — could remain intact close to the black hole’s event horizon while shedding some of its matter. A paper led by Masterson summarizing these results will appear in the Feb. 13 edition of the journal Nature.
This model makes a key prediction, Masterson notes. If the black hole does have a white dwarf companion, the gravitational waves it produces will be detectable by LISA (Laser Interferometer Space Antenna), an ESA mission in partnership with NASA that is expected to launch in the next decade.
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By Francis Reddy
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contacts:
Claire Andreoli
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claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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National Radio Astronomy Observatory, Charlottesville, Va.
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Last Updated Jan 13, 2025 Related Terms
Active Galaxies Astrophysics Black Holes Galaxies, Stars, & Black Holes Goddard Space Flight Center Jet Propulsion Laboratory Neil Gehrels Swift Observatory NICER (Neutron star Interior Composition Explorer) NuSTAR (Nuclear Spectroscopic Telescope Array) Radio Astronomy Supermassive Black Holes The Universe White Dwarfs X-ray Astronomy XMM-Newton (X-ray Multi-Mirror Newton) View the full article
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