Stars are listed in catalogs that give information like the position in coordinates similar to latitude and longitude on the earth , the brightness of the star, its color, and so on. For instance, we often use the Henry Draper catalog designation such as HD for star number in that catalog. There are lots of catalogs with all kinds of names.
Some stars are listed in more than one catalog, so they have more than one name. In ancient times, people looked up at the stars and picked out patterns that they saw. They often associated these patterns with pictures from the stories that they told. Most of the constellations that we use today come from the ancient Romans, and they depict many of the people and animals from their myths. The word constellation means "with" con "stars" stella , and comes from the Latin word constellatio.
As you probably know, a "shooting star" is actually a meteor, a tiny bit of rock in space. Meteors are moving very fast, which is why they burn up when they hit our earth's atmosphere and make a nice, bright "shooting star. But some go as fast as , miles an hour!
The instrument I have used the most to study baby stars is an astronomy satellite called the International Ultraviolet Explorer spacecraft. I studied the ultraviolet light from my baby stars with it for many years to try to understand how they behave.
Ultraviolet light is absorbed by the earth's atmosphere, so the only way to measure it is by using a satellite. Spectroscopes are a very important tool used by astronomers. As you probably realize, astronomers must rely on the light that we can measure from the various astronomical objects. We can't put a star into a laboratory! The spectrum of a star can tell us the temperature, size, and composition of the star. It can also tell us how fast it is moving.
If there are two stars in orbit around each other, a series of measurements can be used to get their masses weights. We can tell if the star has strong magnetic fields. Sometimes we can get the age of the star. Most of what we know about stars has been learned from their spectra!
Stars come in colors from red, orange, yellow, white, bluish-white, and blue. The color depends on how hot the star is. Yes, sometimes it happens. For instance, two stars may start out as a pair in orbit around each other. Then the heavier star which ages faster may become a red giant star, expanding big enough that the outer layers are close to the second star. Then some of the gas in the outer parts of the red giant may get pulled by the second star's gravity and get pulled onto the second star.
If the red giant expands large enough and the second star is close enough, it could even end up inside the red giant star! A brown dwarf is a very small star, so small that it can't produce energy through nuclear reactions the way the normal stars do. It glows mostly in infrared light I guess that's where they came up with the "brown" part, actually it would look deep red to us and is not as bright as other stars.
During its long lifetime, it slowly contracts, gives off infrared light, and gets dimmer and dimmer. It takes a long time — several billion years — for a white dwarf star to completely cool and become a "black dwarf.
If a person mapping the earth is a cartographer, is there a specific name for a person who draws constellations? A cartographer makes maps, and I think it doesn't matter what the map is of. So they can make maps of the earth, the moon, Mars, and the constellations too. It is the closest bright star to the direction of the earth's North Pole, although it isn't exactly at the North Pole.
You may know that the direction of the earth's North Pole changes with time, as the earth very slowly wobbles in a circle every 26, years. Thousands of years ago, other stars were near the North Pole instead of Polaris!
Polaris is a yellow supergiant star. It is a little hotter than our sun, and much bigger and brighter. It is also a star near the end of its life. In fact it has a little variable in its brightness, because it is a little unstable so it pulses, but it won't explode.
It varies in brightness by about ten percent every four days. It is about light-years away. For many hundreds of years, Polaris has been well known as a guide pointing to the North Pole.
The North Star has often been used as a symbol for constancy and faithfulness. In ancient times, it was thought to lie at the point around which the earth spins — as if there were actually a spindle through the earth that stuck into the sky. The Chinese thought that the star was at the top of the heavenly Mountain of the World at the North Pole. In India, the great temples depict the Cosmic Mountain. But here's a funny thing.
Create a List. List Name Save. Rename this List. Rename this list. List Name Delete from selected List. Save to. Save to:. In fact, the Sun's core is so hot and has such high pressure that it undergoes nuclear fusion.
Fusion is the combining to two lightweight elements into a heaver element. In our Sun, the core converts hydrogen into helium. This conversion of hydrogen into helium is the first reaction that happens in every star, it is called the main sequence.
This is because the mass of the combing hydrogen is greater that the end product of helium. Therefore, the mass is converted to energy, and that energy is the electromagnetic radiation light that we get from the Sun! Interactive Applet: Fusion in the Sun! These quantities are related by the mass-energy relation. In , British astronomer Arthur Eddington proposed that the Sun and other stars are powered by nuclear reactions.
Hans Bethe realized that a proton smashing into another proton with enough force could be the reaction to power the Sun. In , Bethe and his colleagues presented a fully developed proton-proton chain of reactions that converts hydrogen into helium, which would allow the Sun to shine for about 10 billion years. Bethe won the Nobel Prize in Physics for his work concerning energy production in stars.
Planet Earth, our bodies, and shining stars are all made of the same basic elements of matter. To understand why stars shine, we must first understand the tiny particles that make up matter. Scientists have studied matter in their laboratories for many, many years.
Each kind of atom has a certain unique number of particles called protons, neutrons, and electrons in it. The protons and neutrons cluster together in the center of the atom in what is called the nucleus. The electrons orbit around the nucleus.
Atoms are very, very small. A hundred million atoms placed side-by-side in a row would only be about 1 inch long! The simplest atom is hydrogen. The nucleus of a hydrogen atom consists of a single proton. Around this proton orbits a single electron.
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