Editing Talk:2707: Astronomy Numbers

Jump to: navigation, search
Ambox notice.png Please sign your posts with ~~~~

Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.

The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Latest revision Your text
Line 39: Line 39:
 
:: ...my conclusion after doing a couple is that we're not going to be satisfied automating (at least with the prompt I was using from here) but it's a useful tool for producing simple explanations if operated manually. [[Special:Contributions/172.71.158.217|172.71.158.217]] 17:54, 7 December 2022 (UTC)
 
:: ...my conclusion after doing a couple is that we're not going to be satisfied automating (at least with the prompt I was using from here) but it's a useful tool for producing simple explanations if operated manually. [[Special:Contributions/172.71.158.217|172.71.158.217]] 17:54, 7 December 2022 (UTC)
  
βˆ’
Why is it as big as 65 mph? Where did the 65 mph figure have come from? A formula? Taking a linear change from minimum velocity (-500 m/s 12 weeks earlier), 4 days before the perihelion gives 86 km/h (53 mph), three days gives just 64 km/h (40 mph). But those are surely too big, since the rate of change of radial velocity would be slowest around perihelion and aphelion. I wouldn't expect the above-calculated rate of change until weeks out from perihelion. [[Special:Contributions/172.68.210.5|172.68.210.5]] 08:23, 6 December 2022 (UTC)
+
Why is it as big as 65 mph? Where did the 65 mph figure have come from? A formula? Taking a linear change from minimum velocity (-500 m/s 12 weeks earlier), 4 days before the perihelion gives 86 kph (53 mph), three days gives just 64 kph (40 mph). But those are surely too big, since the rate of change of radial velocity would be slowest around perihelion and aphelion. I wouldn't expect the above-calculated rate of change until weeks out from perihelion. [[Special:Contributions/172.68.210.5|172.68.210.5]] 08:23, 6 December 2022 (UTC)
 
:Using an ephemeris service, I get 27.6 m/s or 61.8 mph- a bit lower than Randall's record but still in the ballpark. The reason is probably because of the effect of the Moon's orbit on Earth. Of course it's not a huge effect, but when we're working in just a few miles per hour, it definitely has a monthly effect.
 
:Using an ephemeris service, I get 27.6 m/s or 61.8 mph- a bit lower than Randall's record but still in the ballpark. The reason is probably because of the effect of the Moon's orbit on Earth. Of course it's not a huge effect, but when we're working in just a few miles per hour, it definitely has a monthly effect.
βˆ’
:: I did a rough calculation using the position of the Earth-Moon barycentre, and came up with an average Sun-relative radial speed (unsigned velocity) for the Moon of 26 km/h (16 mph). So yes, that could explain some of it, but I still think the contribution of Earth's orbit would be very small around the perihelion (and aphelion). [[Special:Contributions/172.68.66.114|172.68.66.114]] 21:17, 7 December 2022 (UTC)
 
  
 
Surely the really weird thing is an astronomer using non-SI units? [[Special:Contributions/172.70.86.12|172.70.86.12]] 09:40, 6 December 2022 (UTC)
 
Surely the really weird thing is an astronomer using non-SI units? [[Special:Contributions/172.70.86.12|172.70.86.12]] 09:40, 6 December 2022 (UTC)

Please note that all contributions to explain xkcd may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here.
You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see explain xkcd:Copyrights for details). Do not submit copyrighted work without permission!

To protect the wiki against automated edit spam, we kindly ask you to solve the following CAPTCHA:

Cancel | Editing help (opens in new window)

Template used on this page: