For the conception of a child, the maturation of the follicle in the ovary is necessary. If this one...
We all quite often hear that scientists have discovered something or someone on such and such a star or on some planet there, or simply carried out research and ... and so on. But, few people think why the planets are called planets, and the stars are stars, and what important differences do they have, since one was separated from the other? At the same time, almost every one of us at least once in his life asked himself a rather stupid question: “Is the sun a star or a planet?” Also, almost every person will immediately answer this question that the Sun is, of course, a star, but far from everyone is able to explain why it is a star and not a planet.
A logical question arises: what is the difference between a star and a planet?
The difference between them is simply huge, although at first glance it is not very noticeable.
1. First and foremost, stars are able to independently emit light and heat, unlike planets, which are only able to reflect the rays of light falling on them from other luminaries, being inherently dark bodies.
2. Stars have much higher surface temperatures than any known on the planet. this moment planets. The average temperatures of their surfaces range from 2000 to 40000 degrees, not to mention the layers located closer to the center. cosmic body where temperatures may even reach millions of degrees.
Data from SDO, a device studying the Sun, for three years of work
3. Stars are much larger than even the largest planets in their mass.
4. All the planets move in orbits relative to their luminaries, which, in turn, at the same moment remain completely motionless. This is similar to how our Earth revolves around the Sun. Thanks to this, it is possible to observe the different phases of the planets in the same way as the moon.
5. All planets in their chemical composition are formed from both solid and light particles, in contrast to the stars, which mainly consist only of light elements.
6. Planets often have one or several satellites at once, but the stars never have such "neighbors". But at the same time, the absence of a satellite is, of course, not yet a fact that this cosmic body is not a planet.
7. On the surfaces of absolutely all stars, nuclear or thermonuclear reactions accompanied by explosions. In turn, these reactions are not observed on the surfaces of planets, well, if only in exceptional cases, and then only on nuclear planets and only very, very weak nuclear reactions.
You can definitely say...
Now we can absolutely say that the Sun is a typical star (the so-called G-type yellow dwarf). Because 8 planets revolve around it, forming the solar system with it; it radiates light and heat on its own average temperature surfaces 5000-6000 K; consists predominantly of light elements such as hydrogen and helium - almost 99%, and only 1% are solids; thermonuclear reactions are constantly taking place on its surface; and with its size it exceeds several times any planet in the solar system.
Lifeless space is not deserted at all. It combines a huge mass of all kinds of bodies of different nature, sizes and with different name. Among them are meteors, meteorites, comets, fireballs, planets and stars. Moreover, each of the categories of cosmic bodies within itself is also divided into types, the difference between which can often be understood only by an experienced astronomer. For now, let's try to understand the fundamental principles, for example, how stars differ from planets.
Main difference
The very first, basic and undeniable difference is the ability to glow. Any star necessarily emits light, but the planet does not have this property. Of course, nearby planets also look like luminous specks - Venus can serve as an eloquent example. But this is not her own glow, she is just a "mirror", which reflects the light of the true source - the Sun.
By the way, this is very good way how to distinguish a planet from a star purely visually, without additional optical devices. If a luminous dot in the night sky “winks”, that is, flickers, you can be sure that this is a star. If the light emanating from a celestial object is even and constant, then it reflects the light of the nearest luminary. And this is the very first and clear sign showing us how the stars differ from the planets.
The second difference stemming from the first
The ability to emit light is characteristic only of very hot surfaces. As an example, consider a metal that does not glow by itself. But if it is heated to desired temperature, a metal object is heated and radiates, albeit weak, but light.
So the second thing that distinguishes stars from planets is the very high temperature of these cosmic bodies. This is what makes the stars glow. Even on the surface of the coldest star, the temperature does not fall below 2000 degrees K. Usually, stellar temperatures are measured in Kelvin, in contrast to the usual Celsius.
Our Sun is much hotter, in different periods its surface heats up to 5000 or even 6000 K. That is, “in our opinion” it will be 4726.85 - 5726.85 ° C, which is also impressive.
Necessary clarification
These temperatures are typical only for stellar surfaces. Another way stars differ from planets is that they are much hotter inside than outside. Even the surface temperatures on some stars reach 6000 K, and in the center of the stars they presumably go off scale for millions of degrees Celsius! So far, there are neither opportunities, nor the necessary equipment, nor even a calculation formula with which one could determine the internal "degrees" of stars.
Dimensions and movement
The sizes of stars and planets differ just as grandiosely. Compared to the heavenly "lanterns", the planets are just grains of sand. And this applies to both weight (mass) and volume. If instead of the Sun put in the middle free space a medium-sized apple, then to indicate the position of the Earth, you need a pea, referred to hundreds of meters. A comparison of the stars also shows that the volumes of the latter are thousands or even millions of times greater than the volume in space that the former occupy. With a mass of dumb other ratios. The fact is that all the planets - solid bodies. And the stars are mostly gaseous, otherwise, with which the sky-high temperatures of the stars are provided, they would simply be impossible.
What is the difference between a planet and a star? A planet, by definition, has a trajectory of motion called an orbit. And it necessarily surrounds the star as more weighty. The star is motionless in the sky. If you have patience and follow a certain part of the sky for several nights, the movement of the planet can be seen even with a weakly armed eye (but at least you won’t be able to do without an amateur telescope).
Additional Features
The sizes of stars and planets cannot be determined by eye. But some differences that accurately characterize require even more specific equipment. So, chemical composition, which is available to determine by exactly what the planet or star is in front of us. After all, the luminaries are gaseous giants, therefore, they consist of light elements. And the planets include mostly solid components.
An indirect sign may be the presence of a satellite (or even several). They are only found on planets. However, if a satellite is not observed, this does not mean at all that we have a star in front of us - some planets do well without such "neighbors".
Astronomers have another sign of determining whether a newly discovered cosmic body is a planet. The orbit along which it moves should not contain foreign objects, roughly speaking, debris. Satellites are not considered as such, they are quite large in size, otherwise they would have fallen to the surface. This rule was adopted quite recently - in 2006. Thanks to him, Eris, Ceres and - attention! - Pluto is now considered not full, but
Astronomical calculations
Scientists are highly inquisitive. Knowing perfectly well how stars differ from planets, they nevertheless wondered what would happen when the massiveness of the planet exceeded, for example, the size of the Sun. It turned out that such an increase in the size of the planet would lead to a sharp increase in pressure in the core of the cosmic body; then the temperature will reach a million (or several) degrees; nuclear and thermonuclear reactions will begin - and instead of a planet, we will get a newborn star.
