Titanic volcanic eruption seen on Io [Photos r too cool for school]

The new scientist ^ | 11/14/02

[Physicist]

How many gigawatts did it take for the flux capacitor to power the DeLorean back to the future? Was it 1.2 gigawatts?

Of course, Watts are a measure of power, which is energy per unit time, so a 1.2 GW device isn't necessarily out of line with a 12 GW eruption. The eruption operates for a much longer period.

[general_re]

Which means that one side of the moon is facing Jupiter. This type of orbit is called a synchronous orbit.

Ahem. Far be it from me to step on your area of expertise, but isn't a synchronous orbit when the orbital period of a satellite matches the rotational period of the body being orbited? Isn't this, instead, an example of phase-locking, since the rotational period of Io matches the rotational period of Jupiter? After all, you can have a synchronous orbit where the satellite doesn't always display the same face to the orbited body, right?

Signed,
Bewildered in Buffalo

:^)

[general_re]

Isn't this, instead, an example of phase-locking, since the rotational period of Io matches the rotational period of Jupiter its orbital period?

Better.

[RadioAstronomer]

Both are considered synchronous. You also can have a sun-synchronous orbit for a satellite where the satellite is still in orbit around the Earth.

see here is a good description of a sun-synchronous orbit:

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970613a.html

and here we describe the synchronous orbit of our moon:

http://www.trib.com/WYOMING/NCSD/PLANETARIUM/synchronous.html

Your description is completely correct for the geosynchronous satellites at 22,300 (or so) miles over the equatorial belt.

[general_re]

So if I follow you, a phase-locked satellite is also synchronous, but there are synchronous satellites that aren't phase-locked, right?

[RightWhale]

heat waves?

The atmosphere is broken up optically by thermal-induced flow into cells about a yard or less in diameter, give or take. A telescope looking through one cell could be focused sharply, but you can see if a telescope mirror is 2 yards across, it will look through 4 such cells, each with different overall focal length. A solid mirror could not focus for all cells simultaneously, but one with adaptive optics could, to a degree.