101–110 of 274 posts
Would they slow down when they reach another star? What kind of observations can you do if you move at that speed?
From my poor understanding of GR, there will be no limit on the measurements. You just have to take relative motion into consideration when interpreting them.
So the whole thing should weigh in the order of several grams, yet it should be able to deflect 100GW of incoming radiation near perfectly (otherwise it will instantly vaporize) while maintaining structural integrity under the acceleration of 60,000g for two minutes? And whatever laser sources we're using must track this smartphone-sized object during these two minutes across several million kilometers. Perfectly. (I…
10 light-seconds is a massive underestimate. If we assume a constant acceleration from zero to 0.2c over two years, the average speed is 0.1c. Therefore by the end of two years it will be 0.1 lightyears away. Deviations will have to be anticipated over a month in advance!
Earlier quoted context omitted.
From my poor understanding of GR, there will be no limit on the measurements. You just have to take relative motion into consideration when interpreting them.
You move the earth-sun distance in 8 minutes. I am not sure how well you can track with a camera at that speed to get any decent pictures.
Earlier quoted context omitted.
"civilization"? You mean like when Ghandi was (allegedly) asked what he thought of Western Civilization, and replied, "I think it would be a good idea!"
I think they meant the video game. Space race victory
Earlier quoted context omitted.
From my poor understanding of GR, there will be no limit on the measurements. You just have to take relative motion into consideration when interpreting them.
You move the earth-sun distance in 8 minutes. I am not sure how well you can track with a camera at that speed to get any decent pictures.
Also known as an Astronomical Unit (AU).
Ahem.. why does the object have to be behind the solar sail? Cant it be, one object hanging between two solar sails? Or Three? Is there something i dont get here?
So the whole thing should weigh in the order of several grams, yet it should be able to deflect 100GW of incoming radiation near perfectly (otherwise it will instantly vaporize) while maintaining structural integrity under the acceleration of 60,000g for two minutes? And whatever laser sources we're using must track this smartphone-sized object during these two minutes across several million kilometers. Perfectly. (I…
Agreed on the extreme skepticism warranted. I am imagining these "solar sails" to be essentially spherical, both for structural reasons and so that their response to applied laser power does not depend on orientation. The electronics in precision guided mortars in the US army survive 50,000g. http://proceedings.ndia.org/C347/Davis.pdf (This is only for the fraction of a second when they are fired, and I don't know ho…
In this case m ~ 1 gram and a = 0.2c / 120 seconds =499654.097 m/s^2
F = 499654.097 m/s^2 * 1 gram = 500 newtons
However this force is distributed over the whole sail which has an area is 16 m^2, so pressure applied to the sail is 500 N/16 m^2 = 31.25 pascals. This is a fairly low pressure. The pressure change going up or down a couple meters is about equal to this. Your typical cheap garbage bags can withstand this pressure.
How is such thing able to communicate back with earth? Doesn't it require a lot of energy to create signal that we will be able to receive on earth (or satelite)?
Not a scientist but I first read this on The Economist and they summed it up pretty well: "At its destination it would beam back pictures of the star’s planets with its on-board laser. No current observatory could possibly pick up such a signal—but the kilometre-wide launch array should be able to. The optical systems used to meld the output of the lasers could be used in reverse as a vast and sensitive telescope." h…
It seems to me that the accuracy required to aim an unguided projectile anywhere near the target stars will be impossible. They'll fly by pretty far. At what distance to Alpha Centauri does an iPhone quality camera outmatch the Hubble's photos?
“The light beamer must focus a spot smaller than the sail onto the sail, as it orbits 60,000km above the Earth’s surface. This alignment must be produced when the target star system (Alpha Centauri) has the correct configuration with respect to all planetary and stellar bodies in the intervening space, such that the flyby occurs within 2 AU of the target planet. Using on-board photon or others thrusters, the nanocraf…
So the flash can also be used for course corrections? Cool!
So, how is a tiny smartphone-sized probe supposed to transmit data back to Earth from 4.37ly away?
Use the same tech you used to send the first probe to send relay satellites to Alpha Centauri to create an Alpha Centauri-Sol bridge. http://link.springer.com/content/pdf/10.1007%2F978-3-642-274...