Martin Kochanski
  • Member for 5 years, 8 months
  • Last seen more than 1 year ago
How did Arecibo detect methane lakes on Titan, and image Saturn's rings?
12 votes

It did not detect methane lakes. It found that Titan was shiny (in radar terms): that is, the reflections were from a smooth surface rather than a rough one, and at the same time not very intense. ...

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Nicolas Copernicus discovery
Accepted answer
5 votes

Copernicus did not figure out that the Sun was at the centre of the solar system. He merely proposed that a heliocentric model simplified the calculation of planetary orbits. Epicycles (circles within ...

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Why is today the shortest day but the solstice is actually tomorrow?
3 votes

This is an interesting question which opens up wide vistas! Look up the Equation of Time on Wikipedia for a start. What is your source? I can't find the sunrise and sunset times in Ashland. The ESRL ...

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Should the synodic period or the orbital period be used to determine the diameter of the Moon?
Accepted answer
3 votes

What you need, as Aristarchus, is a frame of reference in which the Earth's shadow is stationary. Otherwise you are trying to deal with a moving thing (the Moon) relative to another moving thing (the ...

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Can I learn astrophysics and astronomy with my basic math?
3 votes

For most parts of astronomy and astrophysics the level of mathematics required is not very high, compared to what a mathematician would call mathematics. (You are not going to spend much time on ...

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Is it plausible for a planet that is positioned in the habitable area of a solar system to have little extractable metals?
3 votes

It depends a bit on whether you are talking about extractable metals or about extractable metals. Which is to say: Iron is pretty universal, so if you are thinking about iron and its cousins then ...

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Question about tidal forces and the Roche limit
3 votes

It may also help your mental picture to consider a phenomenon many people see every day. The Earth orbits the Moon quite a distance outside the Moon’s Roche limit. Nevertheless, it is distorted by ...

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Distinction between signal from terrestrial and signals from celestial sources
2 votes

To planetmaker’s excellent answer, add periodicity. This is useful if you can’t measure direction at all. A signal whose intensity varies regularly over a 24-hour period is likely to be terrestrial. A ...

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How do you go from transit times to Earth-Sun distance?
1 votes

We know, precisely, the ratio between the Earth-Venus and Venus-Sun distances. Kepler's laws give us this. We know, in terms of apparent size in the sky, the precise size of the Sun in degrees - just ...

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What is the temperature about 10 or 15 feet below Mars' surface?
1 votes

For a term-paper kind of answer you don't actually need to wait for Mars InSight to tell you. 15 feet is deep enough for you to able to assume that the temperature will be the average of temperatures ...

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Tidal influences of planets on the sun
1 votes

The height of the tidal bulge raised on the Sun by the Earth is about $10^{-13}$ times the radius of the Sun, which is about a 20th of a millimetre. (This presumes that the Sun is made of a ...

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