Some time around 10:31 pm PT tonight, Curiosity will smash into the atmosphere of Mars at 13,000 miles per hour and decelerate to a complete stop over the next 7 minutes. Of course, you can watch live... well, not exactly live since it takes about 15 minutes for the signal from Mars to reach us here on Earth. That means that by the time we get the signal that the Mars Science Lab (MSL - which carries the Curiosity rover) is entering the atmosphere it will already have landed or burned up... we just won't know which. One way or another it will be on the surface of Mars by around 10:23.
So, we here at Digital Diner recommend that you spend the 8 minutes between 10:23 and 10:31 thinking deeply about relativity. The reality of Curiosity's fate will ripple like a wave traveling at the speed of light from Mars out into the universe. We will experience the event of Curiosity arriving at Mars 15 minutes after it occurs there, but really all of time there is offset by 15 minutes. So when does the landing happen? The answer is relative. In fact even the speed of MSL (13,000 mph to 0 mph) is relative to the red planet, not us. Compared to where you sit, the rover may be moving quite quickly because of the rotation of the Earth, Mars and the movement of the planets in their orbits. However, what we care about is that it comes to a gentle stop compared to the surface of Mars. Once again, the speed only has meaning if it is relative to something. Try to explain that to a police officer next time you get pulled over for speeding. When you are asked, "do you know how fast you were going?" reply with, "compared to what?"... or maybe not.
What ever you think about or where ever you are when Curiosity really sets down, be sure that you watch live when time catches up with us here on Earth.
Here is how to watch the landing live(ish)
For those of you in the Bay Area, NASA Ames will have a an event open to the public starting at 4pm today. You can go there to watch live with everyone else at NASA including some of the scientists who worked on the systems that will be put to the test this evening.
You can see where Curiosity is right now here.
And the NASA JPL main mission site is here.