General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or four-dimensional spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever is present, including matter and radiation. The relation is specified by the Einstein field equations, a system of second-order partial differential equations.

Newton's law of universal gravitation, which describes classical gravity, can be seen as a prediction of general relativity for the almost flat spacetime geometry around stationary mass distributions. Some predictions of general relativity, however, are beyond Newton's law of universal gravitation in classical physics. These predictions concern the passage of time, the geometry of space, the motion of bodies in free fall, and the propagation of light, and include gravitational time dilation, gravitational lensing, the gravitational redshift of light, the Shapiro time delay and singularities/black holes. So far, all tests of general relativity have been shown to be in agreement with the theory. The time-dependent solutions of general relativity enable us to talk about the history of the universe and have provided the modern framework for cosmology, thus leading to the discovery of the Big Bang and cosmic microwave background radiation. ..
>> https://en.wikipedia.org/wiki/General_relativity

* relatively related:
https://en.wikipedia.org/wiki/Kerr_metric
https://en.wikipedia.org/wiki/Penrose_process
https://physicsopenlab.org/2017/09/07/spectral-lines-broadening/

* Credits: Wikimedia Commons

#space #blackhole #astronomy #science #nature#NASA#ESA

Explanation:
If one black hole looks strange, what about two? Light rays from accretion disks around a pair of orbiting supermassive black holes make their way through the warped space-time produced by extreme gravity in this detailed computer visualization. The simulated accretion disks have been given different false color schemes, red for the disk surrounding a 200-million-solar-mass black hole, and blue for the disk surrounding a 100-million-solar-mass black hole. For these masses, though, both accretion disks would actually emit most of their light in the ultraviolet. The video allows us to see both sides of each black hole at the same time. Red and blue light originating from both black holes can be seen in the innermost ring of light, called the photon sphere, near their event horizons. In the past decade, gravitational waves from black hole collisions have actually been detected, although the coalescence of supermassive black holes remains undiscovered.
https://www.nasa.gov/universe/new-nasa-visualization-probes-the-light-bending-dance-of-binary-black-holes/
https://apod.nasa.gov/apod/ap200825.html
https://en.wikipedia.org/wiki/Accretion_disk
https://apod.nasa.gov/apod/ap190411.html
https://svs.gsfc.nasa.gov/14132/
https://ui.adsabs.harvard.edu/abs/1993AmJPh..61..619N/abstract
https://apod.nasa.gov/htmltest/rjn_bht.html
https://en.wikipedia.org/wiki/Photon_sphere
https://apod.nasa.gov/apod/ap201104.html

https://apod.nasa.gov/apod/ap250506.html

#space #blackhole #astrophotography #photography #astronomy #science #nature#NASA#ESA

As our viewpoint rotates around the black hole, we see different parts of the fast-moving gas in the accretion disk moving directly toward us. Due to a phenomenon called "relativistic Doppler beaming," gas in the disk that's moving toward us makes that side of the disk appear brighter, the opposite side darker. This effect disappears when we're directly above or below the disk because, from that angle, none of the gas is moving directly toward us.

When our viewpoint passes beneath the disk, it looks like the gas is moving in the opposite direction. This is no different that viewing a clock from behind, which would make it look like the hands are moving counter-clockwise.

CORRECTION: In earlier versions of the 360-degree movies on this page, these important effects were not apparent. This was due to a minor mistake in orienting the camera relative to the disk. The fact that it was not initially discovered by the NASA scientist who made the movie reflects just how bizarre and counter-intuitive black holes can be!

Credit: NASA’s Goddard Space Flight Center
Jeremy Schnittman (NASA/GSFC)
Scott Wiessinger (USRA)
Francis Reddy (University of Maryland College Park)
Francis Reddy (University of Maryland College Park)

>>https://svs.gsfc.nasa.gov/13326#section_credits

#space #blackhole #astrophysics #astrophotography #photography #astronomy #science #nature#NASA#ESA

#ESA#Mars

What you see here isn't a spiral galaxy, exactly. It's a spiral galaxy whose image was bent into a circle by the gravity of an elliptical galaxy visible at the center.

Warped space, right before your eyes!

https://esawebb.org/images/potm2503a/ #space #science #art #nasa #esa

#Asteroid danger explained : "The main challenge stems from the population of middle-size objects, ranging from tens to hundreds of metres in diameter. There are a lot of these asteroids, and most have not been spotted yet." https://www.esa.int/ESA_Multimedia/Images/2018/06/Asteroid_danger_explained

#ESA#AsteroidThreat

#ESA : #Asteroid danger explained https://www.esa.int/ESA_Multimedia/Images/2018/06/Asteroid_danger_explained

#AsteroidThreat

#SpaceStation #launch

#ESA#ElectricPropulsion

* Habitable volume: 10 m3, Launch mass: 10 tonnes https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Gateway_Lunar_I-Hab

#HumanSpaceflightHealth#RadiationProtection#Artemis#LunarGateway

#SpaceWeather#SolarStorm

• #Moon 🌙 deliveries by #Astrobotic, #IntuitiveMachines and #Firefly Aerospace.
• #SPHEREx will create a map of the universe 🌌
• #ESA's 🇪🇺 #SpaceRider #spaceplane orbital test flight
• #Japan's 🇯🇵 lunar lander and micro-rover
• #Tianwen2 🇨🇳 collects samples from a #NEA ☄️
• #BepiColombo at #Mercury
• #EuropaClipper at #Mars
• #NASA’s #Lucy #asteroid flyby
• #JUICE at #Venus
https://www.astronomy.com/space-exploration/space-missions-coming-in-2025

• #SierraSpace#DreamChaser test mission to the #ISShttps://www.planetary.org/articles/calendar-of-space-events-2025

#SpaceX has invested over $5B 💰💰💰💰💰 in #Starship 🚀 R&D to date. Starship has proven its expendable capability, and the company is focusing on achieving full #reusability ♻️.

#NASA spent a dizzying $24B 💰💰💰💰💰💰💰💰💰💰💰💰💰💰💰💰💰💰💰💰💰💰💰💰 developing #SLS
https://payloadspace.com/rocket-development-costs-by-vehicle-payload-research

#DevelopmentCost#LaunchCost