A photo of the Mars Express delay display on the control system, showing us the critical numbers of one-way light time, two-way light time and the distance from Earth.
Mars Express Light Time Delay Display
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Watch the replay: 19 October 2014 - Mars Express team at ESOC monitor the flyby of comet Siding SpringREPLAY: ESAHangout
Watch replay of ESAHangout 22 May 2015 on final preparations for #VMCSchools campaignVMC Imaging Campaign
Information for schools, astronomy clubs, science centres and any other eligible group wishing to take part. Official hashtag: #vmcschools
Discussion: 3 comments
If and when mankind goes to Mars, I think that we should use quantum entanglement as a way to tell mission control (as well as the world) that the spacecraft has landed on the planet. Entangle the particles before launch and then separate the two entangled pair. Keep one on Earth and the other on the space craft. When the craft makes it landing, move or shake the photon on the landing craft. Instantaneously the photon on Earth will change its position; therefore, we would know we had a successful landing. — Just an idea.
Jim Craver
That’s not how quantum entanglement works. You can’t use it to overcome the limitations of speed of light communication.
Entanglement doesn’t mean they move together. It means that when they are observed, they are guaranteed to have opposite spin (spin is a charge-like property) but there is no way to predict or control what that spin will be and once you observe it, the link is broken.
Since you can’t control the outcome you can’t use it to send messages, but the outcome is perfect for cryptographic key exchange in conjunction with a means of actually transferring information.
Think of two boxes. Each has a coin. The guarantee is, no matter how far you move the boxes, when you open either box, one will be heads and one will be tails and the link will be broken. There’s no way to observe the contents other than opening the box, and you have no influence on the contents.