Most of the laws of physics don't care which direction time is travelling. Forwards, backwards… either way, the laws work exactly the same. Newtonian physics, general relativity - time is irrelevant to the mathematics: This is called time-reversal symmetry.
In the real Universe, things get a bit messier. And now a team of scientists led by astronomer Tjarda Boekholt of the University of Aveiro in Portugal have shown that it takes as few as three gravitationally interacting bodies to break time-reversal symmetry.
While you're here, how about this:
China's Long March 2C rocket launches military surveillance satellites into orbit | Space
China successfully launched three new military surveillance satellites into orbit on a Long March 2C rocket today (March 24).
Topped with three Yaogan-30 Group 6 surveillance satellites for the Chinese military, the rocket lifted off from the Xichang Satellite Launch Center in China's Sichuan province at 11:43 a.m. local time (0343 GMT; 11:43 p.m. EDT on March 23).
The three satellites "will be used for electromagnetic environment detection and related technological tests," China's state-run news outlet CCTV reported . The will join China's Chuangxin-5 satellite constellation, which now consists of 18 Yaogan satellites that have been launching in batches of three since the first trio launched in 2017.
There May Be a "Super-Earth" Orbiting the Nearest Star to the Sun : Space : Nature World News
A study on low-mass planet candidate orbiting Proxima Centauri by Mario Damasso and colleagues, published in Science Advances, analyzed the cyclical changes of the light emitted by the star Proxima Centauri. This star is the star nearest our Sun.
Research findings suggest that the star could be orbited by a so-called Super Earth as its second planet.
For more than 15 years, researchers have observed Proxima Centauri with various methods aimed at detecting planetary companions, as mentioned in the publication .
NASA Space Station On-Orbit Status 23 March 2020 - Advanced Biology Research - SpaceRef
Vision tests and a variety of advanced biology research activities took place aboard the International Space Station today.
Each crewmember had a vision acuity test today, with NASA astronaut Andrew Morgan starting first just after lunchtime today. The crew set up a laptop computer with a vision chart and read the characters with one hand over each eye as ground doctors monitored in real-time.
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NASA Flight Engineer Jessica Meir activated a 3-D bioprinter that is being tested for its ability to manufacture human organs in space. She tested the device without printing any cells today and checked its cleaning syringes. The station's Bio-Fabrication Facility could help patients on Earth and enable future crews to produce food and medicines on long-term space missions.
Many things are taking place:
Mapping Martian Dunes from Orbit - Eos
Mars hosts a variety of interesting topography, such as the largest volcano and the biggest canyon in the solar system, as well as rippling sand dunes that constantly shift beneath the planet's thin but windy atmosphere.
Studying how dunes ebb and flow over time can inform scientists about wind, climate, erosion, and sediment availability on the planet's surface. But measuring dunes from space requires multiple images of the same spot, which is not easy to accomplish. NASA's Mars Reconnaissance Orbiter (MRO) tracks how dunes migrate using its High Resolution Imaging Science Experiment (HiRISE) camera.
Bad Astronomy | Octonary stars and 'Broken Pieces': Can the eight-star system from Star Trek:
But roughly half those stars are in fact multiple stars : binaries, trinaries, and even more stars orbiting around each other. From our vantage point of hundreds of trillions of kilometers away, perspective shrinks these systems down to a single point, like a distant car's headlights on a highway merging into one light.
This raises an interesting question: How many stars can you get orbiting each other in a stable pattern?
In the first season of Star Trek: Picard , a plot point revolves (so to speak) around a system of eight stars — an octonary , as it's called.
City Lights From Mumbai to Goa Seen From Orbit - SpaceRef
The city lights of Mumbai to Goa (from bottom left to center right) highlight India's coast on the Arabian Sea as the International Space Station orbited 261 miles above.
NASA Space Station On-Orbit Status 24 March 2020 - Ultrasound Scans and Eye Checks - SpaceRef
Ultrasound scans and eye checks aboard the International Space Station today are helping doctors understand how the Expedition 62 crew is adapting to microgravity.
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NASA Flight Engineer Jessica Meir spent Tuesday morning on biomedical duty and scanned her leg arteries with an ultrasound device. She also attached electrodes to her neck, thigh and heart for the Vascular Echo study. Flight surgeons on the ground monitor the scans real-time to glimpse a crewmember's heart and blood vessel health in space.
Happening on Twitter
Just Three Orbiting Black Holes Can Break Time-Reversal Symmetry, Physicists Find https://t.co/8UuBgjrta6 AlbertEinstein Thu Mar 26 14:27:00 +0000 2020
22 light-years away, there's an exoplanet that one-ups Star Wars' Tatooine – three suns☀️☀️☀️ instead of two☀️☀️ L… https://t.co/YumJF5WV5j NASAExoplanets (from Beyond) Thu Mar 19 17:47:57 +0000 2020
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