Astronomy Questions and Answers

Astronomy is a fascinating subject, but you might be surprised by how much you don’t know about it. Here, we offer a selection of frequently asked questions and answers that will help you get the most out of your stargazing experience.

1) How long does it take for the sun’s rays to reach Earth?

Eight minutes. 2) How many planets are in our solar system? Eight planets, plus the dwarf planets Ceres and Lutetia. The outer gas-giant planets have their own moons, while the inner terrestrial planets have their own rings. The Sun is made of hydrogen and helium, with traces of other elements.

3) Why do stars twinkle? The surface of a star is constantly irradiating its surroundings. The resulting light diffraction causes the stars to appear to twinkle. The speed at which a star moves – or its distance from Earth – affects the apparent brightness as well. The smallest and fastest stars twinkle the most, while the slowest move the least, which is why the astronomical term for twinkle is Doppler effect.

In addition to its own 12 zodiacal constellations, the Moon can also be seen in the constellations Auriga, Cetus, Corvus, Ophiuchus, and Sextans. The outer planets (Jupiter, Uranus, Neptune, and Saturn) can be seen in the constellations Canis Minor, Hydra, Pegasus, and Scutum. The celestial body known as a black hole doesn’t actually contain a singularity, but it can create one. Unlike our own Sun, it’s not hot enough to produce fusion. However, a black hole can pull in surrounding matter and emit electromagnetic radiation.

What were there before the Big Bang? There is no such thing as “before” in astronomy, because time was created during the Big Bang. However, we do have evidence of the Universe as it was in its earliest stages. This is based on the cosmic microwave background (CMB) radiation that astronomers have observed in data collected by satellites.

Astronomers use light-years instead of parsecs to measure astronomical distances, because the former is more familiar to most people. Light-years are used because they can be compared to the speed of light, which is about 187,000 miles per second.

If you want to photograph deep space objects, what is the best way to set your camera? A high ISO value or a low one? Why do people who do CCD imaging stack five 1-minute exposures instead of just one 5-minute exposure? What are the benefits of a high focal ratio vs. a wide aperture in a telescope?