After Decades of Observations, Astronomers have Finally Sensed the Pervasive Background Hum of Merging Supermassive Black Holes
We’ve become familiar with LIGO/VIRGO’s detections of colliding black holes and neutron stars that create gravitational waves, or ripples in the fabric of space-time. However, the mergers between supermassive black holes – billions of times the mass of the Sun — generate gravitational waves too long to register with these instruments.
But now, after decades of careful observations, astronomers around the world using a different type of gravitational wave detection method have finally gathered enough data to measure what is essentially a gravitational wave background hum of the Universe, mostly from supermassive black holes spiraling toward collision.
Scientists say the newly detected gravitational waves are by far the most powerful ever measured, and they persist for years to decades. They carry roughly a million times as much energy as the one-off bursts of gravitational waves from black hole and neutron star mergers detected by LIGO and Virgo.
“It’s like a choir, with all these supermassive black hole pairs chiming in at different frequencies,” said scientist Chiara Mingarelli, who worked about 190 other scientists with the NANOGrav (North American Nanohertz Observatory for Gravitational Waves). “This is the first-ever evidence for the gravitational wave background. We’ve opened a new window of observation on the universe.”
The observatories use the combined power of several radio telescopes. In the US and Canada, the NANOGrav observatories include the now destroyed Arecibo Observatory in Puerto Rico, the Green Bank Telescope in West Virginia, and the Very Large Array in New Mexico. This collaboration collected data from 68 pulsars, to effectively form to form a huge type of detector called a pulsar timing array. Astronomers now announced they have found the first evidence of a consistent background hum of long-wavelength gravitational waves that fills the cosmos.
Also reporting similar results is the European Pulsar Timing Array (EPTA), in collaboration with Indian and Japanese colleagues of the Indian Pulsar Timing Array (InPTA). Observatories there include the Effelsberg Radio Telescope in Germany, the Lovell Telescope of the Jodrell Bank Observatory in the United Kingdom, the Nançay Radio Telescope in France, the Sardinia Radio Telescope in Italy and the Westerbork Radio Synthesis Telescope in the Netherlands.
For this collaboration, 25 years of observing 25 pulsars revealed the gravitational waves with wavelengths much longer than those seen by other experiments.
Pulsars are fast-spinning neutron stars that emit narrow, sweeping beams of radio waves. Credit: NASA Goddard Space Flight Center
“Pulsars are actually very faint radio sources, so we require thousands of hours a year on the world’s largest telescopes to carry out this experiment,” said Dr. Maura McLaughlin of West Virginia University and co-Director of NANOGrav, in a press release. “Now, [our] pulsar observations are showing the first evidence for the presence of gravitational waves, with periods of years to decades.”
“We are incredibly excited that after decades of work by hundreds of astronomers and physicists around the world, we are finally seeing the signature of gravitational waves from the distant Universe.,” said Dr. Michael Keith, from the Jodrell Bank Centre for Astrophysics at The University of Manchester, in another press release. “The results presented today mark the beginning of a new journey into the Universe to unveil some of its unsolved mysteries.
The gravitational wave detections we’ve been reporting on since 2015 by the ground-based LIGO (the Laser Interferometer Gravitational-wave Observatory) and Europe’s Virgo detector are fleeting, high-frequency gravitational waves. A longer, low-frequency signal could be perceived only with a detector much larger than the Earth. By studying the pulsars, astronomers essentially turned our sector of the Milky Way Galaxy into a huge gravitational-wave antenna.
Pulsars are the ultra-dense remnants of the cores of massive stars following their demise in a supernova explosion. Pulsars spin rapidly, sweeping beams of radio waves through space so that they appear to “pulse” when seen from the Earth. The
Review: Patagonia R1 Air Full-Zip Hoody
Hooded Fleece Jacket
Patagonia R1 Air Full-Zip Hoody
$179, 12.5 oz./354g (men’s medium)
Sizes: men’s XS-XXL, women’s XXS-XL, kids XS-XXL
As I’ve repeatedly written at this blog, virtually no piece of outdoor apparel offers more versatility than a highly breathable, midweight insulation layer; arguably, the only “layer” you will wear more is your skin. Find a highly breathable midweight jacket that’s soft and fits like it was custom made for your torso and you have a winner. Patagonia’s R1 Air Full-Zip Hoody could play that role for almost any outdoor user, from hard-core backpackers, climbers, and backcountry skiers to the average dayhiker and fitness walker, as I found wearing it on backpacking trips in Glacier National Park and the Canadian Rockies, not to mention countless days around town and at home.
At 12.5 ounces/354 grams (men’s medium), this midweight fleece is designed for wearing as an outer or middle layer in a huge range of cool to cold temperatures, including activities and seasons as diverse as hiking or climbing in virtually any mountains in any month of the year, southern climes from fall through spring, or for any winter activity—skiing, hiking, running, walking, you pick.
Hi, I’m Michael Lanza, creator of The Big Outside. Click here to sign up for my FREE email newsletter. Join The Big Outside to get full access to all of my blog’s stories. Click here for my e-guides to classic backpacking trips. Click here to learn how I can help you plan your next trip.
The Patagonia R1 Air Full-Zip Hoody.
” data-image-caption=”The Patagonia R1 Air Full-Zip Hoody.
” data-medium-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/09/Patagonia-R1-Air-Full-Zip-Hoody.jpg?fit=300%2C200&ssl=1″ data-large-file=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/09/Patagonia-R1-Air-Full-Zip-Hoody.jpg?fit=900%2C600&ssl=1″ src=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/09/Patagonia-R1-Air-Full-Zip-Hoody.jpg?resize=900%2C600&ssl=1″ alt=”The Patagonia R1 Air Full-Zip Hoody.” class=”wp-image-60252″ srcset=”https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/09/Patagonia-R1-Air-Full-Zip-Hoody.jpg?resize=1024%2C683&ssl=1 1024w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/09/Patagonia-R1-Air-Full-Zip-Hoody.jpg?resize=300%2C200&ssl=1 300w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/09/Patagonia-R1-Air-Full-Zip-Hoody.jpg?resize=768%2C512&ssl=1 768w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/09/Patagonia-R1-Air-Full-Zip-Hoody.jpg?resize=150%2C100&ssl=1 150w, https://i0.wp.com/thebigoutside.com/wp-content/uploads/2023/09/Patagonia-R1-Air-Full-Zip-Hoody.jpg?w=1200&ssl=1 1200w” sizes=”(max-width: 900px) 100vw, 900px” data-recalc-dims=”1″ />The Patagonia R1 Air Full-Zip Hoody.
It kept me warm without overheating—rarely even breaking a sweat—wearing it over one base layer while hiking with a full pack, uphill and downhill, on cool, generally calm mornings and some windy afternoons during a weeklong, nearly 70-mile September backpacking trip in Glacier National Park, and hiking in chilly, very strong wind on three-day hikes on both the Skyline Trail in Jasper National Park and the Nigel, Cataract, and Cline Passes Route in the White Goat Wilderness of the Canadian Rockies in the first week of August.
On those backpacking trips, I also wore it in camp both as an outer layer and, when temps dropped, under a down jacket—meaning the R1 Air Hoody doubled as an on-trail layer and a camp layer that allowed me to bring a lighter puffy and forego a midweight, long-sleeve shirt. To frame it another way: The R1 Air Hoody cut my layering system weight by replacing or reducing two other layers. Few pieces of apparel offer more versatility while reducing your pack weight.
I also wore it on breezy, cool evenings in the 50s between waves of thunderstorms
Did you miss our previous article…
Gaia is Now Finding Planets. Could it Find Another Earth?
The ESA launched Gaia in 2013 with one overarching goal: to map more than one billion stars in the Milky Way. Its vast collection of data is frequently used in published research. Gaia is an ambitious mission, though it seldom makes headlines on its own.
But that could change.
Gaia relies on astrometry for much of its work, and astrometry is the measurement of the position, distance, and motions of stars. It’s so sensitive that it can sometimes detect the slight wobble a planet imparts to its much more massive star. Gaia detected its first two transiting exoplanets in 2021, and it’s expected to find thousands of Jupiter-size exoplanets beyond our Solar System.
But new research takes it even further. It shows that Gaia should be able to detect Earth-like planets up to 30 light-years away.
The new paper is “The Possibility of Detecting our Solar System Through Astrometry,” and is available on the pre-press site arxiv.org. It has a single author: Dong-Hong Wu from the Department of Physics, Anhui Normal University, Wuhu, Anhui, China.
Astronomers find most exoplanets with the transit method. A spacecraft like TESS monitors a section of the sky and looks at many stars at once. When a planet passes between us and one of the stars, it’s called a transit. It creates a dip in starlight that TESS’s sensitive instruments can detect. When TESS detects multiple, predictable dips, it signifies a planet.
But that’s not the only way to detect them. Astrometry can do it too, and that’s Gaia’s way.
Astrometry has an advantage over other methods. Gaia can more accurately determine an exoplanet’s orbital parameters. This doesn’t mean the other methods aren’t valuable. They obviously are. But as the paper’s author explains, “Neither the transit nor radial velocity method provides complete physical parameters of one planet, and both methods prefer to detect planets close to the central star. On the contrary, the astrometry method can provide a three-dimensional characterization of the orbit of one planet and has the advantage of detecting planets far away from the host star.” Astrometry’s advantages are clear.
If other technological planetary civs exist—and that’s a big if—then it’s not outrageous to think they have technology similar to Gaia’s. While Gaia is impressive, there are improvements on the horizon that will make astrometry even more precise. The author asks a question in his paper: If ETIs (ExtraTerrestrial Intelligences) are using advanced astrometry equal to or even surpassing Gaia’s, “…which of them could discover the planets in the solar system, even the Earth?”
Astrometrical precision is calculated in microarcseconds, and precision decreases with distance. The ESA says that Gaia can measure a star’s position within 24 microarcseconds for objects 4000 times fainter than the naked eye. That’s like measuring the thickness of a human hair from 1000 km away. But that’s not precise enough for Wu’s scenario. His work is based on even more advanced astrometry, the type we’ll likely have in the near future. “If the astrometry precision is equal to or better than ten microarcseconds, all 8,707 stars located within 30 pcs of our solar system possess the potential to detect the four giant planets within 100 years.”
This is the heart of Wu’s paper. The 30-parsec (approx. 100 light-years) region contains almost 9,000 stars, and if an ETI from one of those stars has powerful enough astrometry, then it could detect Jupiter, Saturn, Uranus, and Neptune. The only drawback is they’d have to observe our Solar System for nearly a century to make sure the signal was clear.
1,” the author writes. Image Credit: Wu 2023.” class=”wp-image-163369″ srcset=”https://www.universetoday.com/wp-content/uploads/2023/09/Giant-Planet-Detection.png 492w, https://www.universetoday.com/wp-content/uploads/2023/09/Giant-Planet-Detection-374×580.png 374w, https://www.universetoday.com/wp-content/uploads/2023/09/Giant-Planet-Detection-161×250.png 161w” sizes=”(max-width: 492px) 100vw, 492px” />
This figure from the research shows how long it would take for an ETI with advanced astrometry to detect our Solar System’s four giant planets. “We find that all the four giants in our solar system could be detected and well-characterized as long as they are observed for at least 90 years with SNR > 1,” the author writes. Image Credit: Wu 2023.
There are 8707 stars within 100
Finally! Astronomers are Starting to See the First Galaxies Coming Together With JWST
One of the James Webb Space Telescope’s principal science goals is to observe the epoch where we think that the first galaxies were created, to understand the details of their formation, evolution, and composition. With each deep look back in time, the telescope seems to break its own record for the most distant galaxy ever seen. Science papers are now are starting to trickle in, as astronomers are finally starting to collect enough data from JWST to build a deeper understanding of the early Universe.
In a new study published in Nature Astronomy, a team of researchers in Denmark believe they have observed some of the very first, earliest galaxies with JWST. These galaxies are so old, they are likely still in the process of being formed.
One known standard is that the ratio between galaxies and their heavy elements has held constant in the local Universe through the last 12 billion years of history, or about 5/6 of the age of the Universe. But with JWST, astronomers are now seeing that the youngest galaxies look different. They don’t have that same ratio of stars to heavier elements because they haven’t gone through the cycles of star formation and star death yet, enriching gas clouds with metals, i.e., elements heavier than hydrogen and helium.
This plot shows the observed galaxies in an “element-stellar mass diagram”: The farther to the right a galaxy is, the more massive it is, and the farther up, the more heavy elements it contains. The gray icons represent galaxies in the present-day Universe, while the red show the new observations of early galaxies. These ones clearly have much less heavy elements than later galaxies, but agree roughly with theoretical predictions, indicated by the blue band. Credit: Kasper Elm Heintz, Peter Laursen.
For this study, the astronomers looked at 16 galaxies, some of the earliest galaxies ever observed. Their observations revealed that the chemical abundances in these galaxies are one-fourth of that seen in galaxies that were formed later. In their paper, the astronomers wrote that “these findings suggest that galaxies at this time are still intimately connected with the intergalactic medium and subject to continuous infall of pristine gas, which effectively dilutes their metal abundances.”
As gravity gathered together the first clumps of gas,the first stars and galaxies were formed.
“When we analyzed the light from 16 of these first galaxies, we saw that they had significantly less heavy elements, compared to what you’d expect from their stellar masses and the amount of new stars they produced,” said Kasper Elm Heintz, leader of the study and assistant professor at the Cosmic Dawn Center at the Niels Bohr Institute and DTU Space in Copenhagen, Denmark, in a press release.
These results, the astronomers say, are in stark contrast to the current model where galaxies evolve in a form of equilibrium throughout most of the history of the Universe, where there is a relationship between how many stars have formed and how many heavy elements have formed.
Illustration of galaxy formation: Diffuse gas from intergalactic space plummets toward the center, sparking star formation and becoming part of the galaxy’s rotating disk. When stars die, they return their gas to the galaxy (and the intergalactic space), now enriched with heavy elements. Credit: Tumlinson et al. (2017)
Did you miss our previous article…
Fashion3 years ago
Steampunk Clothing & Jewelry
Sports3 years ago
Best Christmas Gift For Your Golfer Co-Worker
Fashion3 years ago
Best Timepieces To Buy For The Holiday Season
Motor3 years ago
2022 Infiniti QX55 Carigami Can Be Yours
Trending Stories3 years ago
Dior Homme Cologne Men’s Fragrance Review
Uncategorized3 years ago
How To Attract Women Easily (Without Talking)
Grooming3 years ago
Trimmed Penis – 5 Common Pubic Hairstyles For Men
Mens Health4 years ago
8 Things I Do Before 8 Am: My Morning Routine