Comments on: Questions Show: Shooting Lasers at the Moon and Losing Contact with Rovers http://www.astronomycast.com/listeners/questions-shows/questions-show-shooting-lasers-at-the-moon-and-losing-contact-with-rovers/ Take a weekly facts-based journey through the cosmos with Astronomy Cast. Tue, 09 Mar 2010 17:33:19 +0000 http://wordpress.org/?v=2.9.1 hourly 1 By: Tanya http://www.astronomycast.com/listeners/questions-shows/questions-show-shooting-lasers-at-the-moon-and-losing-contact-with-rovers/comment-page-1/#comment-1658 Tanya Fri, 27 Mar 2009 19:47:24 +0000 http://www.astronomycast.com/?p=642#comment-1658 I thought there was a slight mistake in Pamela's answer on the gravity train. The train ALWAYS takes the same time on its journey (neglecting friction). I forgot if it's 84 minutes or 42 minutes, but it's always the same time. We did this problem in our college physics class. The first part was it going through the center of the earth. The second was with just a slight slope as in Fraser's example of LA-SF. Cheers Tanya I thought there was a slight mistake in Pamela's answer on the gravity train. The train ALWAYS takes the same time on its journey (neglecting friction). I forgot if it's 84 minutes or 42 minutes, but it's always the same time. We did this problem in our college physics class. The first part was it going through the center of the earth. The second was with just a slight slope as in Fraser's example of LA-SF.

Cheers

Tanya

]]> By: Amro http://www.astronomycast.com/listeners/questions-shows/questions-show-shooting-lasers-at-the-moon-and-losing-contact-with-rovers/comment-page-1/#comment-1631 Amro Fri, 20 Mar 2009 01:00:40 +0000 http://www.astronomycast.com/?p=642#comment-1631 Re the pebble orbiting Hubble question, here’s another answer to a similar question “Can an astronaut orbit the space shuttle?” at http://www.asterism.org/tutorials/tut22-1.htm I’ve come across the above page a while ago so just thought I’d swing the link over. The answer is essentially no as Pamela said, but the page at the above link expands a little... Re the pebble orbiting Hubble question, here’s another answer to a similar question “Can an astronaut orbit the space shuttle?” at

http://www.asterism.org/tutorials/tut22-1.htm

I’ve come across the above page a while ago so just thought I’d swing the link over. The answer is essentially no as Pamela said, but the page at the above link expands a little…

]]> By: SF Reader http://www.astronomycast.com/listeners/questions-shows/questions-show-shooting-lasers-at-the-moon-and-losing-contact-with-rovers/comment-page-1/#comment-1619 SF Reader Tue, 17 Mar 2009 13:34:10 +0000 http://www.astronomycast.com/?p=642#comment-1619 Irwin, the essence is that the tunnels, while straight, will all have different slopes, and so the acceleration will be different. The shorter tunnels will have gentler slopes, the longest tunnels will be closer to vertical. So, the peak and overall speed will be higher in the longer tunnels. Does that help? Dennis Irwin, the essence is that the tunnels, while straight, will all have different slopes, and so the acceleration will be different. The shorter tunnels will have gentler slopes, the longest tunnels will be closer to vertical. So, the peak and overall speed will be higher in the longer tunnels.

Does that help?

Dennis

]]> By: Yellllllll http://www.astronomycast.com/listeners/questions-shows/questions-show-shooting-lasers-at-the-moon-and-losing-contact-with-rovers/comment-page-1/#comment-1613 Yellllllll Mon, 16 Mar 2009 12:37:43 +0000 http://www.astronomycast.com/?p=642#comment-1613 Does anybody could tell me where is the text about the audio? Does anybody could tell me where is the text about the audio?

]]> By: Irwin http://www.astronomycast.com/listeners/questions-shows/questions-show-shooting-lasers-at-the-moon-and-losing-contact-with-rovers/comment-page-1/#comment-1612 Irwin Mon, 16 Mar 2009 04:36:21 +0000 http://www.astronomycast.com/?p=642#comment-1612 Loved the podcast. I always do. There was a question that Frasier asked Pamela about whether the time for a gravity train would be the same, regardless of the length of the tunnel. Totally coincidentally, I was reading a book by Martin Gardner, Puzzling Questions About the Solar System, and question 5 was about - gravity trains. He says that the time would be the same, regardless of the length- the time it would take to fall the entire distance through the earth (42 minutes). Could someone possibly give an intuitive explanation of why this is true? Thanks. Loved the podcast. I always do.

There was a question that Frasier asked Pamela about whether the time for a gravity train would be the same, regardless of the length of the tunnel. Totally coincidentally, I was reading a book by Martin Gardner, Puzzling Questions About the Solar System, and question 5 was about – gravity trains. He says that the time would be the same, regardless of the length- the time it would take to fall the entire distance through the earth (42 minutes). Could someone possibly give an intuitive explanation of why this is true? Thanks.

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