Astronomy Cast Ep. 160- Eclipses

Eclipses occur when one object passes between two objects in the line of sight and blocks the light given off by one object. Transits are when small things cross a larger but don't completely block all of the light. Occultation is when something in our solar system blocks the light from an object in another solar system. All are forms of eclipses. Eclipses don't happen every month because the moon's orbit is inclined. Solar Eclipses occur at new moon at certain times during the year. The moon is at the exact right distance to have full eclipses. Since the moon's orbit is elliptical, annular eclipses can occur because the moon's angular size is not large enough to completely block out the light of the sun. The changing distances between the moon, Earth, and Sun affect the kind of eclipse that occurs (annular or full). Hybrid eclipses are when some areas see annular eclipses, and some see full eclipses. You have to be in the shadow to see the solar eclipse, while anyone on Earth can see a lunar eclipse. Lunar eclipses occur during full moon. The light we see on the lunar surface during a lunar eclipse is caused by light being refracted by our atmosphere. Lunar eclipses can either occur in the lighter penumbra or darker umbra. Transits of Venus and Mercury can be seen across the sun, and transits of Jupiter's moons across Jupiter can also be seen (and other moon/planet systems). On Jupiter, these transits appear as solar eclipses. We can use transits to calculate the distance between the Earth, Venus and the Sun. This uses trigonometry be using the Earth's diameter as one side of a triangle, the distance as another, and the location of a planet on the sun's disk from different latitudes to create an angle. Pinhole cameras create an image of the eclipse on the ground. Use filters until totality, then you can watch the totality with the naked eye. A lunar eclipse requires no safety precautions. When extrasolar planets travel in front of a star, we can make measurements about the stars and planets because of the variability in light. Thus, we can discover Earth-like planets orbiting other stars.

Although I already knew most of the information presented in the telecast, it was very informative and i still learned a great deal about the workings of eclipses. Each minute was very informative to me as an astronomy student.