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ppauper
Posts: 63683
Joined: November 15th, 2001, 1:29 pm

Re: News from Outer Space

May 27th, 2017, 10:01 am

Image

this is the jovian south pole captured by the juno spacecraft
the ovals are cyclones up to 600 miles across
multiple images were combined
 
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Topic Author
Posts: 25603
Joined: August 28th, 2008, 1:53 pm

Re: News from Outer Space

June 19th, 2017, 6:22 pm

Looking for something spooky?

Quantum entanglement at a record distance - Science News June 15

"Quantum entanglement—physics at its strangest—has moved out of this world and into space. In a study that shows China's growing mastery of both the quantum world and space science, a team of physicists reports that it sent eerily intertwined quantum particles from a satellite to ground stations separated by 1200 kilometers, smashing the previous world record. The result is a stepping stone to ultrasecure communication networks and, eventually, a space-based quantum internet."

More from the article:

"In their first experiment, the team sent a laser beam into a light-altering crystal on the satellite. The crystal emitted pairs of photons entangled so that their polarization states would be opposite when one was measured. The pairs were split, with photons sent to separate receiving stations in Delingha and Lijiang, 1200 kilometers apart. Both stations are in the mountains of Tibet, reducing the amount of air the fragile photons had to traverse. This week in Science, the team reports simultaneously measuring more than 1000 photon pairs. They found the photons had opposite polarizations far more often than would be expected by chance, thus confirming spooky action over a record distance (though the 2015 test over a shorter distance was more stringent)."

And here is the original paper in Science:

Satellite-based entanglement distribution over 1200 km - Science June 16 2017
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rmax
Posts: 5810
Joined: December 8th, 2005, 9:31 am

Re: News from Outer Space

July 3rd, 2017, 11:43 am

Experiment to study the effect of knocking an asteroid out of orbit.

http://www.theregister.co.uk/2017/07/03/nasa_bring_on_the_asteroid_so_we_can_chuck_a_fridge_at_it/
 
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Traden4Alpha
Posts: 22520
Joined: September 20th, 2002, 8:30 pm

Re: News from Outer Space

July 3rd, 2017, 4:33 pm

rmax wrote:
Experiment to study the effect of knocking an asteroid out of orbit.

http://www.theregister.co.uk/2017/07/03/nasa_bring_on_the_asteroid_so_we_can_chuck_a_fridge_at_it/
Kinetic deflection has never seemed like that good an idea to me. The coupling of the impactor's limited energy into the body seems too unreliable to induce a predictable ∆V. Worse, either an off-center impact or a heterogeneous asteroid composition seems too likely which means the vector angle of the ∆V is poorly controlled.

My favorite option is landing some sort of ion engine on the surface and using low, but relentless thrust to push the asteroid in some desired direction. It seems to offer the advantage of better control, interim feedback, and adjustment as well as a greater total ∆V over time. (Extra credit if the device can harvest dust or rock from the surface to provide mass for the thruster).

I also liked the nuclear option. What it lacks in efficiency is more than made up for in total energy.
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