Connect with us

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.

Screenshot 2023 06 29 095245 1
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

Continue Reading

Frontier Adventure

Why is Jupiter’s Great Red Spot Shrinking? It’s Starving.

Jupiter Great Red Spot Juno 580x386 1

The largest storm in the Solar System is shrinking and planetary scientists think they have an explanation. It could be related to a reduction in the number of smaller storms that feed it and may be starving Jupiter’s centuries-old Great Red Spot (GRS).

This storm has intrigued observers from its perch in the Jovian southern hemisphere since it was first seen in the mid-1600s. Continuous observations of it began in the late 1800s, which allowed scientists to chart a constant parade of changes. In the process, they’ve learned quite a bit about the spot. It’s a high-pressure region that generates a 16,000 km-wide anticyclonic storm with winds clocking in at more than 321 km per hour. The storm extends down through the atmosphere to a depth of about 250 km below the mainly ammonia cloud tops.

A zoomed-in view of the Great Red Spot based on Juno observations. Courtesy Kevin Gill.
A zoomed-in view of the Great Red Spot based on Juno observations. Courtesy Kevin Gill.

Modeling a Shrinking and Growing Great Red Spot

Over the past century, scientists noticed the GRS shrinking, leaving them with a puzzle on their hands. Yale Ph.D. student Caleb Keaveney had the idea that perhaps smaller storms that feed the GRS could play a role in starving it. He and a team of researchers focused on their influence and conducted a series of 3D simulations of the Spot. They used a model called the Explicit Planetary Isentropic-Coordinate (EPIC) model, which is used in studying planetary atmospheres. The result was a suite of computer models that simulated interactions between the Great Red Spot and smaller storms of varying frequency and intensity.

A separate control group of simulations left out the small storms. Then, the team compared the simulations. They saw that the smaller storms seemed to strengthen the Great Red Spot and make it grow. “We found through numerical simulations that by feeding the Great Red Spot a diet of smaller storms, as has been known to occur on Jupiter, we could modulate its size,” Keaveney said.

If that’s true, then the presence (or lack thereof) of those smaller storms could be what’s changing the spot’s size. Essentially, a lot of smaller spots cause it to grow larger. Fewer little ones cause it to shrink. Furthermore, the team’s modeling supports an interesting idea. Without forced interactions with these smaller vortices, the Spot can shrink over a period of about 2.6 Earth years.

Using Earth Storms as a Comparison

The Great Red Spot isn’t the only place in the Solar System that sports such a long-lived high-pressure system. Earth experiences plenty of them, usually called “heat domes” or “blocks.” Most of us are familiar with heat domes because we experience them during the summer months. They happen frequently in the upper atmosphere jet stream that circulates across our planet’s mid-latitudes. We can blame them for some of the extreme weather people experience—such as heat waves and extended droughts. They tend to last a long time, and they are linked to interactions with smaller transient weather such as high-pressure eddies and anticyclones.

Given that the Great Red Spot is an anticyclonic feature, it has interesting implications for similar atmospheric structures on both planets, according to Keaveney. “Interactions with nearby weather systems have been shown to sustain and amplify heat domes, which motivated our hypothesis that similar interactions on Jupiter could sustain the Great Red Spot,” he said. “In validating that hypothesis, we provide additional support to this understanding of heat domes on Earth.”

The Ever-changing Great Red Spot

In addition to the changing size of the Great Red Spot, observers also notice shifts in its color. It’s mainly reddish-orange but has been known to fade to a pinkish-orange hue. The colors suggest some complex chemistry occurring in the region spurred by solar radiation. It has an effect on a chemical compound called ammonium hydrosulfide as well as the organic compound acetylene. That creates a substance called a tholin, which gives a reddish color wherever it exists.

At times the spot has nearly disappeared altogether due to some complex interaction with a feature called
Did you miss our previous article…
https://mansbrand.com/review-patagonia-black-hole-pack-32l-travel-pack-2/

Continue Reading

Frontier Adventure

Review: Patagonia Black Hole Pack 32L Travel Pack

Wind4 016 200x200 1

Travel Pack
Patagonia Black Hole Pack 32L

$169, 32L/1,831 c.i., 1 lb. 12.6 oz./810g

One size

backcountry.com

If you’re like me, whenever you’re flying somewhere for a few days, maybe a week or more, you ask yourself the same question: Can I do this without checking luggage? Not only do I loathe paying a luggage fee, but I don’t want to give an airline the opportunity to lose my luggage. Plus, I like the convenience, low expense, and the ethically and morally correct choice (in this age of climate crisis) of using public transportation to and from airports—which is really only feasible when carrying one small, light, portable bag or pack. For me, the carry-on of choice is the Patagonia Black Hole Pack 32L.

For starters, I generally like having a small and light pack or bag with shoulder straps that I can throw onto my back to move quickly through airports; wheeled luggage of any size quickly loses its convenience when you’re in a serious rush in an airport, have no choice but to go up or down stairs (which I prefer, anyway, to standing on an escalator behind a line of stationary people), or are taking subways, buses, or trains.

Wind4 016 200x200 2
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 Black Hole Pack 32L back panel and shoulder straps.
” data-image-caption=”The Patagonia Black Hole Pack 32L back panel and shoulder straps.
” data-medium-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/07/06224812/Patagonia-Black-Hole-Pack-32L-harness-2.jpg?fit=225%2C300&ssl=1″ data-large-file=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/07/06224812/Patagonia-Black-Hole-Pack-32L-harness-2.jpg?fit=768%2C1024&ssl=1″ tabindex=”0″ role=”button” src=”https://i0.wp.com/tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/07/06224812/Patagonia-Black-Hole-Pack-32L-harness-2-768×1024.jpg?resize=768%2C1024&ssl=1″ alt=”The Patagonia Black Hole Pack 32L back panel and shoulder straps.” class=”wp-image-59669″ style=”width:602px;height:auto” srcset=”https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/07/06224812/Patagonia-Black-Hole-Pack-32L-harness-2.jpg 768w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/07/06224812/Patagonia-Black-Hole-Pack-32L-harness-2.jpg 225w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/07/06224812/Patagonia-Black-Hole-Pack-32L-harness-2.jpg 640w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/07/06224812/Patagonia-Black-Hole-Pack-32L-harness-2.jpg 150w, https://tbo-media.sfo2.digitaloceanspaces.com/wp-content/uploads/2023/07/06224812/Patagonia-Black-Hole-Pack-32L-harness-2.jpg 900w” sizes=”(max-width: 768px) 100vw, 768px” data-recalc-dims=”1″ />The Patagonia Black Hole Pack 32L back panel and shoulder straps.

On my most recent trip, flying cross-country to visit family and friends—two flights and a layover of 90 minutes or more in each direction—I wanted to avoid checking luggage (for all the reasons given above). Packing frugally, I fit everything I needed into my Black Hole Pack 32L for
Did you miss our previous article…
https://mansbrand.com/pulsars-are-the-ideal-probes-for-dark-matter/

Continue Reading

Frontier Adventure

Pulsars are the Ideal Probes for Dark Matter

pulsar 1024x576 7

Pulsars are the remnants of the explosion of massive stars at the end of their lives. The event is known as a supernova and as they rapidly spin they sweep a high energy beam across the cosmos much like a lighthouse. The alignment of some pulsar beams mean they sweep across Earth predictably and with precise regularity. They can be, and often are used as timing gauges but a team of astronomers have found subtle timing changes in some pulsars hinting at unseen mass between pulsars and telescopes—possibly dark matter entities.

The discovery in 1967 of pulsars has revolutionised our understanding of stellar evolution. The are formed during the collapse of supermassive stars at the end of their life. As the fusion in the core ceases, the inrushing stellar material crashing down onto the core compresses it to incredible density. The material that once made up the star is, through this process compressed into a sphere just a few tens of kilometres across. Pulsars are closely related to neutron stars which are formed though the same process and it is believed, the only difference is that one has a highly energetic beam that flashes across the Earth and one doesn’t. 

pulsar 1024x576 8
Visualization of a fast-rotating pulsar. Credit: NASA’s Goddard Space Flight Center Conceptual Image Lab

A team studying pulsars has recently detected hints of potential dark matter objects through changes in pulsar timing events as they rotate. Professor John LoSecco from the University of Notre Dame, presented at the National Astronomy Meeting at the University of Hull and emphasised the precision of pulsar-based timekeeping. “Science has advanced with precise time measurement methods,” he noted, comparing Earth’s atomic clocks with pulsars in space. While gravitational effects on light have been understood for over a century, their applications in uncovering hidden masses remain largely unexplored until now.

Professor LoSecco and the team noted tiny deviations in the pulsar timing, suggesting that radio waves may be getting redirected around an unseen mass located somewhere between the pulsar and the telescope. LoSecco theorised that the masses could potentially be dark matter!

By examining the delays and analysing the radio pulse arrivals (which were typically accurate to within a nanosecond) they explored the pathway of radio signals within the latest Parkes Pulsar Timing Array survey. Other telescopes involved in this initiative were the Effelsberg, Nançay, Westerbork, Green Bank, Arecibo, Parkes, and the Lovell telescope in Cheshire. Using this and Parkes data, the pulse arrival times were analysed.

UCF Arecibo aerial 1024x683 4
The Arecibo Radio Telescope Credit: UCF

The results showed that the pulses occur regularly every three weeks across three observational bands. However, when dark matter causes delays in arrival times, these delays display distinct shapes proportional to the mass of the dark matter. Regions with dark matter slow down the passage of light and effect the pulsar timings. The Sun for example, could produce a delay of about 10 microseconds however the timing differences 10,000 times smaller.  A detailed examination of precise data from 65 ‘millisecond pulsars’ has identified approximately twelve instances suggestive of interactions with dark matter.

Source : How astronomers are using pulsars to observe evidence of dark matter

The post Pulsars are the Ideal Probes for Dark

Continue Reading

Trending