Difference between revisions of "Talk:681: Gravity Wells"
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[[Special:Contributions/87.174.225.131|87.174.225.131]] 07:21, 12 April 2013 (UTC) | [[Special:Contributions/87.174.225.131|87.174.225.131]] 07:21, 12 April 2013 (UTC) | ||
:Best guess is either a goof, or that the lower number is just for Earth itself, while the greater number is for the Earth/Moon system as a whole. Proportionally speaking, we have the largest moon in the solar system, so maybe it wouldn't nicely fit in the Earth well as easily as Mars's and Jupiter's moons do.--[[User:Druid816|Druid816]] ([[User talk:Druid816|talk]]) 08:28, 12 April 2013 (UTC) | :Best guess is either a goof, or that the lower number is just for Earth itself, while the greater number is for the Earth/Moon system as a whole. Proportionally speaking, we have the largest moon in the solar system, so maybe it wouldn't nicely fit in the Earth well as easily as Mars's and Jupiter's moons do.--[[User:Druid816|Druid816]] ([[User talk:Druid816|talk]]) 08:28, 12 April 2013 (UTC) | ||
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+ | : It ''may'' be the height needed to go from one gravity well to another. You don't have to get all the way up to escape speed for that. | ||
+ | |||
+ | |||
+ | :Adapted from the table in {{w|Escape_velocity#List_of_escape_velocities|Escape velocity}}, using ''h'' = ''V_e''^2 / 2''g'': | ||
+ | {| class="wikitable" border="1" | ||
+ | | Location || with respect to || Ve (km/s) || Well depth (km) || | ||
+ | | Location || with respect to || Ve (km/s) || Solar well (Mm) || Total depth (Mm) | ||
+ | |- | ||
+ | | on the Sun, || the Sun's gravity: || 617.5 || 19,435,000 || || || || || || 19,435 | ||
+ | |- | ||
+ | | on Mercury, || Mercury's gravity: || 4.3 || 942 || | ||
+ | | at Mercury, || the Sun's gravity: || 67.7 || 233.6 || 235 | ||
+ | |- | ||
+ | | on Venus, || Venus' gravity: || 10.3 || 5,407 || | ||
+ | | at Venus, || the Sun's gravity: || 49.5 || 124.9 || 130 | ||
+ | |- | ||
+ | | on Earth, || the Earth's gravity: || 11.2 || 6,393 || | ||
+ | | at the Earth/Moon, || the Sun's gravity: || 42.1 || 90.3 || 97 | ||
+ | |- | ||
+ | | on the Moon, || the Moon's gravity: || 2.4 || 294 || | ||
+ | | at the Moon, || the Earth's gravity: || 1.4 || || 91 | ||
+ | |- | ||
+ | | on Mars, || Mars' gravity: || 5 || 1,274 || | ||
+ | | at Mars, || the Sun's gravity: || 34.1 || 59.3 || 61 | ||
+ | |- | ||
+ | | on Jupiter, || Jupiter's gravity: || 59.5 || 180,400 || | ||
+ | | at Jupiter, || the Sun's gravity: || 18.5 || 17.4 || 198 | ||
+ | |- | ||
+ | | on Ganymede, || Ganymede's gravity: || 2.7 || 372 || || || || || | ||
+ | |- | ||
+ | | on Saturn, || Saturn's gravity: || 35.6 || 64,600 || | ||
+ | | at Saturn, || the Sun's gravity: || 13.6 || 9.43 || 74 | ||
+ | |- | ||
+ | | on Uranus, || Uranus' gravity: || 21.2 || 22,907 || | ||
+ | | at Uranus, || the Sun's gravity: || 9.6 || 4.7 || 28 | ||
+ | |- | ||
+ | | on Neptune, || Neptune's gravity: || 23.6 || 28,400 || | ||
+ | | at Neptune, || the Sun's gravity: || 7.7 || 3.02 || 31 | ||
+ | |- | ||
+ | | on Pluto, || Pluto's gravity: || 1.2 || 73 || || || || || | ||
+ | |- | ||
+ | |at Solar System <br/>galactic radius, || the Milky Way's gravity: || 525 || 14,000 | ||
+ | |} | ||
+ | : Randall wasn't kidding about the Sun being "very very far down"; its well is 100 times deeper than Jupiter's! | ||
+ | :[[User:Wwoods|Wwoods]] ([[User talk:Wwoods|talk]]) 19:47, 12 April 2013 (UTC) |
Revision as of 19:47, 12 April 2013
Why is Earth's well's depth listed as 5478km but as 6379km in the inset? Compare with Mars which has 1286 in both places. 87.174.225.131 07:21, 12 April 2013 (UTC)
- Best guess is either a goof, or that the lower number is just for Earth itself, while the greater number is for the Earth/Moon system as a whole. Proportionally speaking, we have the largest moon in the solar system, so maybe it wouldn't nicely fit in the Earth well as easily as Mars's and Jupiter's moons do.--Druid816 (talk) 08:28, 12 April 2013 (UTC)
- It may be the height needed to go from one gravity well to another. You don't have to get all the way up to escape speed for that.
- Adapted from the table in Escape velocity, using h = V_e^2 / 2g:
Location | with respect to | Ve (km/s) | Well depth (km) | Location | with respect to | Ve (km/s) | Solar well (Mm) | Total depth (Mm) | |
on the Sun, | the Sun's gravity: | 617.5 | 19,435,000 | 19,435 | |||||
on Mercury, | Mercury's gravity: | 4.3 | 942 | at Mercury, | the Sun's gravity: | 67.7 | 233.6 | 235 | |
on Venus, | Venus' gravity: | 10.3 | 5,407 | at Venus, | the Sun's gravity: | 49.5 | 124.9 | 130 | |
on Earth, | the Earth's gravity: | 11.2 | 6,393 | at the Earth/Moon, | the Sun's gravity: | 42.1 | 90.3 | 97 | |
on the Moon, | the Moon's gravity: | 2.4 | 294 | at the Moon, | the Earth's gravity: | 1.4 | 91 | ||
on Mars, | Mars' gravity: | 5 | 1,274 | at Mars, | the Sun's gravity: | 34.1 | 59.3 | 61 | |
on Jupiter, | Jupiter's gravity: | 59.5 | 180,400 | at Jupiter, | the Sun's gravity: | 18.5 | 17.4 | 198 | |
on Ganymede, | Ganymede's gravity: | 2.7 | 372 | ||||||
on Saturn, | Saturn's gravity: | 35.6 | 64,600 | at Saturn, | the Sun's gravity: | 13.6 | 9.43 | 74 | |
on Uranus, | Uranus' gravity: | 21.2 | 22,907 | at Uranus, | the Sun's gravity: | 9.6 | 4.7 | 28 | |
on Neptune, | Neptune's gravity: | 23.6 | 28,400 | at Neptune, | the Sun's gravity: | 7.7 | 3.02 | 31 | |
on Pluto, | Pluto's gravity: | 1.2 | 73 | ||||||
at Solar System galactic radius, |
the Milky Way's gravity: | 525 | 14,000 |