Re:Philae’s first touchdown seen by Rosetta
by mckoss on Sunday November 16, 2014 @01:32AM
(#8613604)
It looks like you can see the lander, up in the air and casting a shadow on the surface in the 2nd image. If it is, you can get a good estimate of its horizontal velocity from the image timestamp.
Re:Philae’s first touchdown seen by Rosetta
by pcrh on Sunday November 16, 2014 @10:14AM
(#8614349)
That speck appears to be there in the first image as well, though not as bright...?
I wonder if Philae actually landed exactly where computed (the green square), and if so why the dark dust does not radiate from that spot, but "down-wards". Perhaps Philae hit the surface at an angle?
Re:Philae’s first touchdown seen by Rosetta
by valevk on Sunday November 16, 2014 @05:45AM
(#8613912)
Did the lander somehow adjust itself while hovering away from the original landing site? I can't imagine Philae bouncing away, then flying for roughly one hour (?) and then landing on its feet.
Re:Philae’s first touchdown seen by Rosetta
by throwaway_yy2Di on Sunday November 16, 2014 @11:13AM
(#8614525)
Gravity exerts almost no torque here. Philae has 100 kg of inertia, but it weighs less than a feather.
Even if were in a strong gravity field, that still wouldn't orient it, if there's no force like air resistance to attenuate its tumbling. It can rotate indefinitely in the vertical plane: there's no loss of energy. (In an atmosphere, this rotation is damped by air drag, so gravity can orient things).
https://plus.google.com/app/basic/stream/z13gzxiwdkq2clyew22...
I wonder if Philae actually landed exactly where computed (the green square), and if so why the dark dust does not radiate from that spot, but "down-wards". Perhaps Philae hit the surface at an angle?
Even if were in a strong gravity field, that still wouldn't orient it, if there's no force like air resistance to attenuate its tumbling. It can rotate indefinitely in the vertical plane: there's no loss of energy. (In an atmosphere, this rotation is damped by air drag, so gravity can orient things).