lifeless space is not deserted.It combines a huge mass of all sorts of bodies of different nature, size and with different names.Among them - the meteors, meteorites, comets, fireballs, planets and stars.And each of the categories of cosmic bodies inside still divided on the types of differences that can often be understood only astronomer with the experience.Let's try to sort out until the fundamental principles, for example, what the stars are different from planets.
main difference
very first, basic and is not subject to question the distinction - the ability to glow.Any Star necessarily emits light, the planet also has this property.Of course, nearby planets also look luminous spots - an eloquent example of this is Venus.But it's not her own glow, it is just a "mirror" that reflects the light of the true source - the sun.
By the way, this is a very good way how to distinguish the planet from the star purely visually, without additional optics.If the point of light in the night sky "winks", ie flickers - rest assured, it is a star.If coming from the celestial object are smooth and continuous - so is the planet reflects light nearest star.This is the first and most obvious sign that shows us what the stars are different from planets.
second difference arising from the first
ability to emit light characteristic of only a very hot surfaces.As an example we can consider the metal, which in itself does not light.But if it is heated to the desired temperature, the metal object is heated and radiates albeit weak, but light.
so that the second than the stars differ from planets - a very high temperature of these cosmic bodies.It allows stars to shine.Even on the surface of the cold light temperature does not drop below 2000 degrees K. Usually stellar temperature measured in Kelvin, unlike our usual Celsius.
Our Sun is much hotter in different periods of its surface is heated up to 5000 or even 6000 K. That is "our way" it will 4726.85 - 5726.85 ° C, which is also impressive.
need to clarify
These temperatures are typical only for stellar surfaces.More than the stars differ from the planet, so it is the fact that inside they are much hotter than outside.Even surface temperatures on some stars reach 6000 K, and in the center of the light they are supposedly going wild over millions of degrees Celsius!So far, no capacity nor the necessary equipment, or even a formula calculation by which it would be possible to determine the internal "degree" of stars.
size and dimensions
movement of stars and planets differ just great.Compared with the heavenly "lights" of the planet - just a grain of sand.And this applies to the weight (mass), and volume.If, instead of the sun in the middle of space to put a medium-sized apple, then to indicate the position of the Earth need a pea allocated to hundreds of meters.Compare the size of the planets and the stars shows that the volume of second in the thousands, and even millions of times greater than the amount of space that is occupied by the first.With a mass of silent other ratios.The fact that all the planets - solids.And the stars are mainly gaseous, or thermonuclear reactions, which provide fantastically high temperatures of the stars, would be impossible.
But what distinguishes a planet from a star yet?Planet, by definition, has a motion path, called an orbit.And she certainly surrounds star as more substantial celestial body.Star motionless in the sky.If you have patience and a few nights to monitor certain parts of the sky, the movement of the planets can be seen with the naked eye, even slightly (but at least no amateur telescopes do not work).
Additional features
dimensions of the stars and planets did not identify by eye.But some differences that accurately characterize the cosmic body, require more specific equipment.For example, a chemical compound that is available for spectral analysis to determine exactly say, a planet or a star before us.After all, the world - it's gaseous giants, therefore, they are composed of light elements.A planet include primarily solid components.
indirect sign of the presence of the satellite can be (and sometimes more).They are only the planets.However, if the satellite is not observed, this does not mean that this is a unique star - planet some good cost and without such "neighbors."
Astronomers have another sign of determining whether the planet has just discovered the cosmic body.The orbit at which it is moving, must be free of foreign objects, roughly debris.The satellites are not considered, they are quite large in size, otherwise I would have fallen to the surface.Such a rule adopted quite recently - in 2006.Thanks to him, Eris, and Ceres - attention!- Pluto is now considered to be not full and dwarf planets.
astronomical calculations
Scientists have a high curiosity.Knowing full well what the stars are different from the planets, they nevertheless were curious what happens when massive planet will surpass, for example, the size of the sun.It turned out that such an increase in size of the planet will lead to a sharp increase in pressure in the core of the cosmic body;Further temperature reaches million (or more) degrees;start nuclear and thermonuclear reactions - and instead we get the planet newborn stars.
