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#gravitational waves
personal-through · 20 hours
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mindblowingscience · 1 month
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Scientists may soon be able to detect the most mysterious entity in the universe using a fleet of next-generation satellites, a new theoretical study suggests. Dark matter — a poorly understood substance that does not emit, absorb or reflect light but exerts a clear gravitational influence on other matter — dominates the universe. Despite being more than five times more abundant in space than ordinary matter, dark matter's composition and properties remain entirely unknown.
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aspaceinthecosmos · 9 months
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hello! i've got some GROUNDBREAKING space news for you!
scientists have uncovered evidence for a gravitational wave background (GWB) in our universe, and the way they went about it is fascinating.
To fully understand what's going on here, we need to go into a bit of background information.
First of all: what are gravitational waves? gravitational waves are often called 'ripples' in spacetime, often caused by extremely energetic processes such as black holes colliding, or two neutron stars orbiting each other closely.
So, how did scientists figure this out? They used 67 pulsars (known as the Pulsar Timing Array) throughout the Milky Way, practically creating a galaxy-sized telescope in order to study this.
Pulsars are the extremely dense cores of massive stars, left over after they go supernova. These are fascinating on their own, but for this project, they had an essential feature: Pulsars rapidly rotate (think up to hundreds of rotations per second), spewing radiation out in pulses from their magnetic poles. For some pulsars, these radiation jets cross Earth's line of sight, and we get incredibly constant bursts of radio signals, which can be catalogued and used as a sort of standard, universal clock.
Here is a link to a gif showing the rotation of a pulsar. Please be warned for flashing and eyestrain.
For 15 years, a team of astronomers working for the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), used radio telescopes around the globe to track minuscule changes in the signal patterns from pulsars. The changes they found are due to the slight movement of spacetime between us and the pulsars, stretching and compressing the paths of their radio waves as extremely low frequency gravitational waves pass through the universe (yes, that includes you. your atoms, as well as the atoms making up everything around you, are very slowly shifting position, dancing along to the heartbeat of the universe).
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At the moment, scientists are still debating what could have caused this gravitational wave background, but some there are some leading theories: the GWB could be caused by trillions of binary black hole systems (black holes orbiting each other) throughout the universe. It could also be due to cosmic inflation, or even the big bang itself. Scientists just don't know yet, but the opportunities this discovery opens up are incredible.
The knowledge of the GWB could help us better understand the formation of early galaxies, or even help us understand the origin of the universe.
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spacetime-singularity · 11 months
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Black Holes and Gravitational waves lecture notes 🗒️ ✨
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autistic-af · 29 days
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@bettergobackoutandfindher
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This is an oven crypt:
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Popular in the American south, especially New Orleans, they were popular cheap options for family burial.
A crypt could be rented out for a while, and once the "lease" was up, the crypt would be opened, the bones pushed back into the interior spaces and a new body interred.
Many of these crypts are no longer used, as you can see above, and are in disarray. But they are an amazing part of history.
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kid-yard · 4 days
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mindblowingscience · 9 months
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Scientists say they are starting to find signs of an elusive type of rumbling through space that could be created by the biggest, baddest black holes in the universe. The discovery means that astrophysicists may have opened a whole new window onto supermassive black holes. These mysterious, extremely dense objects, millions to billions of times more massive than the sun, sit at the center of galaxies like our own. When two galaxies merge, the enormous black holes at their centers are thought to come together and circle each other in a spinning dance that sends giant waves spiraling out. These waves are like the ripples that move through a pond if you toss in a rock — only these waves move through the very fabric of the universe, and researchers have been eager to study them. "We've been on a mission for the last fifteen years to find a low-pitched hum of gravitational waves resounding throughout the universe," says Stephen Taylor, a Vanderbilt University astrophysicist who serves as the chair of a team of researchers known as the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). "We're very happy to announce that our hard work has paid off."
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admit-hair · 18 days
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*smug smile*
*breathes in* & *breathes out*
OK, I HAVE TO share.
Pulsars in the Milky Way as a large-scale observatory for the gravitational wave background!!! 🌌
*excitedly chirps*
✨️What are gravitational waves?✨️
Gravitational waves propagate at the speed of light & cause a periodic stretching & squeezing of the narrow web of space & time - they occur when galaxies merge & black holes orbit each other!
This means that if a gravitational wave passed between us & say two merging black holes, the actual amount of space between the two objects will change. The merging black holes will be closer to or farther away from us as the gravitational wave passes through without either the black holes or Earth having moved at all!
And here's the big deal: The flashes of light from a pulsar at a certain distance from Earth will always hit Earth at the same intervals, because it will always take the light the same amount of time to travel from there to here.
But if there’s suddenly more space between the pulsar & Earth, it will take the light longer to travel from there to here & therefore the clock-like timing will be thrown off!
Gravitational wave detectors on Earth have been developed to measure the effects of short waves that occur when two stellar-mass black holes orbit close together & eventually merge.
Long gravitational waves from the active early universe can't be measured directly from Earth since we are simply not able to build a wave detector that big, but gravitational waves do change the clock frequency of pulsar stars!
✨️What are pulsars?✨️
Pulsars are stellar remnants (dead stars) that emit radio waves in two opposite directions while rotating around an axis. If the cone of radio beams passes over the Earth, the pulsar can be measured by its periodic radio pulses.
Pulsars can help to spot gravitational waves from black holes that are supermassive, millions to billions times larger than our sun.
In comparison, the Laser Interferometer Gravitational-Wave Observatory (LIGO) network can only detect gravitational waves originating from smaller black holes that are up to 10 times as massive as the sun.
✨️The Gravitational Wave Background not to be confused with the Cosmic Microwave Background✨️
The gravitational wave background is theorised as a faint but persistent echo of gravitational waves to have been set off by events that took place shortly after the Big Bang & the merging of supermassive black holes throughout the universe.
Signals of these gravitational waves that make up that background have been hard to detect due to being faint, in addition to vibrating at decade-long timescales, but using those dead stars to measure these long gravitational waves might do the trick!
And GUESS WHAT HAPPENED? 🌟
They found something!
✨️A hum.✨️
In a globally coordinated announcement on June 28, different teams of scientists reported the discovery of a "low pitch hum" of these cosmic ripples flowing through the Milky Way!
Hints of the same signal were announced in a series of papers published by scientists in China, India, Europe and Australia. They say the signals may be coming from merging supermassive black holes that are caught in cosmic dances, circling each other in orbits that shrink across millions of years. During this process, they release energy in the form of gravitational waves that reverberate throughout the universe, waves that they claim to now have detected.
Of course, there is to consider that dust, gas & interstellar medium can also cause the timing of the pulses of a pulsar to deviate, but the new research claim, the "critical evidence" that betrays the source of the signals to be supermassive black holes is a unique pattern found in the arrival times of pulses from a galaxy-sized cosmic antenna of nearly 70 millisecond pulsars in the Milky Way by using 15 years of data.
Gravitational wave signals from black hole binaries overlap "like voices in a crowd" & result in an incessant hum that embeds as a unique pattern in the pulsar timing data, scientists say.
The detection of the gravitational wave background is going to open up an entirety of new studies for scientists to probe the biggest mysteries in our universe, from neutron stars to galaxy formation. It may even allow to probe new physics & fill in some of the gaps in the Standard Model.
And it turns out, the universe is loud. Not only is the background there, it’s stronger than anyone anticipated.
There are a few potential reasons for that excessive 'volume.' For one, there could just be many more merging black holes than we thought there were. For another, String Theory suggests that there might be deformations in spacetime called "cosmic strings" producing the waves.
If you believe in the Big Bounce instead of the Big Bang, the waves could be coming from that as well. And there’s always the chance that pulsars just aren’t quite as perfect as we thought.
And I, as you may know, ABSOLUTELY ADORE
✨️String Theory ✨️
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mysticstronomy · 7 months
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HOW FAST DOES THE EARTH SPIN??
Blog#331
Wednesday, September 13th, 2023
Welcome back,
To answer the question of how fast Earth spins, you need to know two things: how long it takes to make a full rotation, and Earth’s circumference. The time it takes Earth to rotate so the sun appears in the same position in the sky, known as a solar day, is 24 hours. However, the time it takes Earth to complete one full rotation on its axis with respect to distant stars is actually 23 hours 56 minutes 4.091 seconds, known as a sidereal day.
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With this information, to work out how fast Earth is spinning we need only our planet’s circumference. At the equator, its circumference is roughly 40,075 kilometres, so dividing this by the length of day means that, at the equator, Earth spins at about 1670 kilometres per hour.
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However, this speed of rotation isn’t consistent across the planet. As you move north or south, the circumference of Earth gets smaller, so the speed of spin reduces until it reaches its slowest at both poles. And all of this is nothing compared with the 107,000 kilometres per hour at which Earth orbits the sun.
If we are travelling so fast through space, why can’t we feel it?
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Simply put, as Earth is spinning at a constant speed, so does everything on it. Travelling at the same speed means we cannot feel the spin. It is like driving a car. Even though you are moving, you aren’t aware of speed because it is constant. Only when you change speeds do you notice you are travelling, like putting your foot on the accelerator or making an emergency stop.
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A change in speed has been happening here on Earth, but it is far too slow to notice. Millions of years ago, one Earth day was about 22 hours, and Earth’s speed has been dropping for more than a billion years, with days increasing by around 2 milliseconds every century.
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This slow down is caused by friction created by the ocean currents, tides and wind pulling on Earth’s surface. However, global warming may speed things up again. As sea levels rise, this change in mass could result in Earth spinning faster and reducing the length of each day by 0.12 milliseconds, which would have dramatic effects on the calibration of atomic clocks and GPS systems.
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What if Earth were to stop spinning?
Without a huge external force, this is impossible. But, if Earth were to stop spinning, the atmosphere would continue to spin at the speed of Earth’s rotation, so anything not fixed to the surface, including trees and buildings, would be swept away by the strong winds.
Each side of the planet would get six months of continuous sunlight and six months of darkness.
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Without the centrifugal force of the spin, the oceans would gradually move towards the poles, creating a huge supercontinent across the equator. But we wouldn’t be flung off Earth. Gravity and the centrifugal force of Earth’s spin keep us grounded. In order for us to feel weightless, the centrifugal force would need to be ramped up. At the equator, Earth would need to spin at 28,437 kilometres per hour for us to be lifted off into space.
Originally published on newscientist.com
COMING UP!!
(Saturday, September 16th, 2023)
"HOW DO WE KNOW THE UNIVERSE IS INFINITE??"
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rubiscodisco · 9 months
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Science influencers keep saying "the universe is humming" because of the pulsar timing array just discovered the Gravitational Wave Background of low frequency waves, when it's objectively better to say that the universe is wobbling like freestanding custard or flan
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