To grasp the vastness of space, Voyager 1 will pass near Gliese 445 in about 40,000 years. Yet even then, it will hardly have traveled across the galaxy. One full orbit of the Milky Way would require over 400 million years—an unimaginable timescale.

Learn more: https://science.nasa.gov/mission/voyager/mission-overview/

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Crossing into interstellar space in 2012, Voyager 1 marked a milestone in exploration. Yet on a galactic scale, its motion is almost imperceptible. Even after drifting for a million years, it would remain within the Orion Spur, close to its origins.

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bonus... #astrophysics https://dst.gov.in/new-window-stars-modeling-stellar-atmosphere

The Sound of Two Black Holes Colliding

Gravitational waves sent out from a pair of colliding black holes have been converted to sound waves, as heard in this animation. On September 14, 2015, LIGO observed gravitational waves from the merger of two black holes, each about 30 times the mass of our sun. The incredibly powerful event, which released 50 times more energy than all the stars in the observable universe, lasted only fractions of a second.

In the first two runs of the animation, the sound-wave frequencies exactly match the frequencies of the gravitational waves. The second two runs of the animation play the sounds again at higher frequencies that better fit the human hearing range. The animation ends by playing the original frequencies again twice.

As the black holes spiral closer and closer in together, the frequency of the gravitational waves increases. Scientists call these sounds "chirps," because some events that generate gravitation waves would sound like a bird's chirp.

Audio Credit:
Caltech/MIT/LIGO Lab
ligo.caltech.edu

2021 December 7

Ninety Gravitational Wave Spectrograms and Counting
* Image Credit: NSF, LIGO, VIRGO, KAGRA, Georgia Tech, Vanderbilt U.
https://www.nsf.gov/
https://www.ligo.org/about.php
http://public.virgo-gw.eu/the-virgo-collaboration/
https://gwcenter.icrr.u-tokyo.ac.jp/en/organization
https://physics.gatech.edu/
https://as.vanderbilt.edu/physics/
* Graphic : Sudarshan Ghonge & Karan Jani
https://humansofligo.blogspot.com/2019/05/sudarshan-ghonge.html
https://www.karanjani.com/

Explanation:
Every time two massive black holes collide, a loud chirping sound is broadcast out into the universe in gravitational waves. Humanity has only had the technology to hear these unusual chirps for the past seven years, but since then we have heard about 90 -- during the first three observing runs. Featured above are the spectrograms -- plots of gravitational-wave frequency versus time -- of these 90 as detected by the giant detectors of LIGO (in the USA), VIRGO (in Europe), and KAGRA (in Japan). The more energy received on Earth from a collision, the brighter it appears on the graphic. Among many science firsts, these gravitational-radiation chirps are giving humanity an unprecedented inventory of black holes and neutron stars, and a new way to measure the expansion rate of our universe. A fourth gravitational wave observing run with increased sensitivity is currently planned to begin in 2022 December.

https://spaceplace.nasa.gov/gravitational-waves/en/

https://dcc.ligo.org/LIGO-G2102338/public
https://ligo.org/science-summaries/O3bAstroDist/

https://apod.nasa.gov/apod/ap211207.html

2018 December 3

Spiraling Supermassive Black Holes
* Video Credit: NASA's Goddard Space Flight Center
https://www.nasa.gov/
https://www.nasa.gov/goddard
* Music: In the Hall of the Mountain King by Edvard Grieg
https://en.wikipedia.org/wiki/In_the_Hall_of_the_Mountain_King
https://en.wikipedia.org/wiki/Edvard_Grieg

Explanation:
Do black holes glow when they collide? When merging, co-orbiting black holes are sure to emit a burst of unusual gravitational radiation, but will they emit light, well before that, if they are surrounded by gas? To help find out, astrophysicists created a sophisticated computer simulation. The simulation and featured resulting video accurately depicts two spiraling supermassive black holes, including the effects of Einstein's general relativity on the surrounding gas and light. The video first shows the system from the top, and later from the side where unusual gravitational lens distortions are more prominent. Numerical results indicate that gravitational and magnetic forces should energize the gas to emit high-energy light from the ultraviolet to the X-ray. The emission of such light may enable humanity to detect and study supermassive black hole pairs well before they spiral together.

https://apod.nasa.gov/apod/ap181203.html

"Om Nano Paeme Hum ;) "

2023 June 29

A Message from the Gravitational Universe
* Illustration Credit: NANOGrav Physics Frontier Center;
https://nanograv.org/
* Text: Natalia Lewandowska (SUNY Oswego)
https://ww1.oswego.edu/physics/

Explanation:
Monitoring 68 pulsars with very large radio telescopes, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has uncovered evidence for the gravitational wave (GW) background by carefully measuring slight shifts in the arrival times of pulses. These shifts are correlated between different pulsars in a way that indicates that they are caused by GWs. This GW background is likely due to hundreds of thousands or even millions of supermassive black hole binaries. Teams in Europe, Asia and Australia have also independently reported their results today. Previously, the LIGO and Virgo detectors have detected higher-frequency GWs from the merging of individual pairs of massive orbiting objects, such as stellar-mass black holes. The featured illustration highlights this spacetime-shaking result by depicting two orbiting supermassive black holes and several of the pulsars that would appear to have slight timing shifts. The imprint these GWs make on spacetime itself is illustrated
by a distorted grid.

https://en.wikipedia.org/wiki/Radio_telescope
https://nanograv.org/science/overview
https://nanograv.org/science/topics/low-frequency-gravitational-waves
https://en.wikipedia.org/wiki/Gravitational_wave_background
https://nanograv.org/news/15yrRelease
https://www.seti.org/news/nanogravs-15-year-journey-reveals-a-cosmic-hum/
https://astrobites.org/2018/01/29/hunting-for-gravitational-waves-from-spinning-neutron-stars/

https://apod.nasa.gov/apod/ap230629.html