Article

2006-09-04 Science & Technology

Europe's first moon probe ends mission with a bang

Archived material is restricted to Rantburg regulars and members. If you need access email fred.pruitt=at=gmail.com with your nick to be added to the members list. There is no charge to join Rantburg as a member.

Posted by lotp 2006-09-04 00:00|| || Front Page|| [4 views since 2007-05-07] Top

#1 The amusing thing about this mission was the ion drive. Early on, it proved to be working, which resulted in a big stimulus to making better ion drive.

So before it had gotten anywhere near the Moon, they had already invented one or two generations more advanced and efficient engines.

The next ion-drive launch will probably be for a probe that is a lot larger and going a lot further.

Right now there is a ton of research going into creating a J.S. Bell(*) communications device, which can communicate instantly over vast distances. If that is a success, then we will be throwing big, ion-drive probes outside of the solar system on all sorts of missions.

(*) When the matched spin of one of a matched pair of particles is changed, the spin of the other one changes, no matter where it is located. Thus a probe outside our solar system could send equivalent to faster-than-light transmissions by changing the spin of its single particles, and their matched twins back on Earth would also change. Instructions could also be sent back to the probe this way, and there would be no need for massive antennas and huge bursts of energy to do so.

Posted by Anonymoose 2006-09-04 11:28|| 2006-09-04 11:28|| Front Page Top

#2 No, Anonymoose. That's not how quantum mechanics works. You can't use that effect to communicate anything faster than light. When you measure partcle A's spin for the first time, particle B will have the opposite spin when you measure it, but you can't force particle A to spin up and therefore force particle B to spin down. QM isn't that spooky.

You can use this for quantum cryptography. You designate before hand a subset of the photons you send as the key for a later message. You measure your photons' spins, and you get the key. If no one intercepts the photons on their way to your correspondant, then they get the inverse of your key, and you're set. If anyone intercepts either the key or the actual message, then it randomizes the message, and no one gets any useful information.

You only use a small proportion of the photons you send for the key so an interceptor can't figure out the key from your transmission even if he intercepts it.

QM entanglement does not imply faster-than-light information transfer.

Posted by Eric Jablow">Eric Jablow 2006-09-04 12:01|| 2006-09-04 12:01|| Front Page Top

#3 There was an article in Scientific Unamerican about how entanglement did not violate Einstein's postulate regarding the speed of light.

Posted by Perfesser 2006-09-04 13:51|| 2006-09-04 13:51|| Front Page Top

#4 Sci. Am. hasn't been any good since Martin Gardner left.

Posted by Eric Jablow">Eric Jablow 2006-09-04 19:36|| 2006-09-04 19:36|| Front Page Top

23:45 Zenster
23:38 Zenster
23:34 Zenster
23:27 Zenster
23:23 Swamp Blondie
23:21 gromgoru
23:17 gromgoru
23:13 gromgoru
23:10 gromgoru
23:03 gromgoru
22:59 trailing wife
22:56 Francis
22:49 GK
22:48 Zenster
22:48 RD
22:45 RD
22:39 Barbara Skolaut
22:35 Zenster
22:30 trailing wife
22:19 Frank G
22:16 trailing wife
22:10 Texas Redneck
21:57 Old Patriot
21:45 Old Patriot