a man leaves earth on a space ship sending a flash signal to earth every 6 minutes.the observser on earth sees the flash every 12 minutes.on his return to earth he sends a flash every 6 minutes and the observer sees the flash every
3 minutes.this is not a trick question.
2006-09-13 10:56:50 · 9 answers · asked by art 1 in Science & Mathematics ➔ Physics
its not relativity or faster than light travel. its actually plain and simple old doppler effect. quite boring really
EDIT: I'm going to clarify one more time, relativity has NOTHING to do with the explanation of this. as the question says, "IT'S NOT A TRICK." essentially, if doppler wasnt the cause then travelling away from the planet the acclerated frame astronaut would send the signal every six minutes, which due to time dilation would stretch to twelve minutes... okay, so far relativistics as the cause seems makes sense, right? well, on the way back the astronaut (accelerated frame) would be travelling faster than the rest frame. time would STILL slow down. so if relativity was the cause, then when he sent it every six minutes, you would still see it every twelve minutes. uh oh, i guess relativistics isn't the right topic here after all... the ONLY explanation which fits the concept of the problem is the doppler effect. and to others: STOP CORRECTING THE SCIENTISTS... seriously, i have 165,000 dollars worth of college education under my belt, i THINK i have some idea of what i'm talking about when it comes to something as simple as this.
one more edit, just for my amusement... discounting relativistic time dilation, on his way back he'd be heading in at half the speed of light (assuming that he's using light for whatever a "flash" signal is). Again assuming a flash signal means light, i *think* he'd have to be travelling away from the planet AT the speed of light. again, this is unrealistic. first, relativistic time dilation would STOP time at that speed and second, masseous objects simply can't travel at the speed of light. the reason i say *think* is because it's 1:30 in the morning and i refuse to draw out a picture and/or work any calculations at the moment. Good night, i'm going to bed.
2006-09-13 11:01:03 · answer #1 · answered by promethius9594 6 · 1⤊ 0⤋
The spaceship is traveling at the speed of light on the way out, and at half the speed of light on the way back.
Leaving earth: Let's have the first flash be just as the ship is leaving, at t=0 minutes. The observer on earth sees it right away.
At t=6 minutes, the ship flashes again. The ship is 6 light minutes away, so the flash reaches earth at t=12.
At t=12, the ship flashes again. The ship is 12 light minutes away, so the flash reaches earth at t=24.
Returning to earth: The ship is traveling at half the speed of light.
Let's say the ship starts 12 light minutes away.
At t=0, the ship flashes. The flash reaches earth at t=12.
At t=6, the ship flashes. The ship is 9 light minutes away. The flash reaches earth at t=15.
At t=12, the ship flashes. The ship is 6 light minutes away. The flash reaches earth at t=18.
I'd like the problem better if the ship were traveling at the same speed both ways, but apparently that's not the case...
2006-09-13 18:15:20 · answer #2 · answered by Bramblyspam 7 · 0⤊ 1⤋
The speed of light is a constant. Time is a variable. Therefore, the astronaut sends the signal every 6 minutes according to his time. From the receiver's point of time, the signal is sent every 12 minutes. No contradiction... just prove of relativity in action.
Why people with degrees in science give wrong answers, I do not know.
2006-09-13 22:17:14 · answer #3 · answered by Willem V 3 · 0⤊ 1⤋
I think all of the above are wrong.The speed of light does not change no matter where it was sent.Doppler effect does not change the speed as well it only change the wave length.
For this reasons,the question is impossible.If the light source is 6 light minutes away it will take 6 minutes to reach to the observer.May be he will see red colour when the spaceship is leaving and violet ehen it is approaching.
2006-09-13 20:26:57 · answer #4 · answered by dwarf 3 · 0⤊ 1⤋
This is doppler's effect. Read about them.
Also look for redshift etc whic explains the motion of objects
2006-09-13 18:32:55 · answer #5 · answered by Dr M 5 · 1⤊ 0⤋
Travelling at twice the speed of light.
2006-09-13 17:59:50 · answer #6 · answered by RANDLE W 4 · 0⤊ 1⤋
it's relativity
time slows down for the person traveling at a high rate of speed
2006-09-13 17:59:21 · answer #7 · answered by Anonymous · 0⤊ 1⤋
to me that sounds like the ship is travelling fast enough to cause a visible distortion in time.
2006-09-13 18:02:24 · answer #8 · answered by nerdyhermione 4 · 0⤊ 1⤋
Its like how light travel.. or when a star dies.... the farder it is the longest it takes to reach us...
2006-09-13 18:04:41 · answer #9 · answered by Roxy 3 · 0⤊ 1⤋