How can the elements H and He in a star be transformed into other elements?

That is thermonuclear fusion through the nucleus of an atom.

Nuclear fusion is a nuclear reaction in which lighter nuclei "coalesce" into heavier nuclei. The Sun has been engaged in nuclear fusion for 5 billion years: two hydrogen nuclei fuse into a deuterium nucleus, plus a positron and neutrino; At the same time, megaelectron volts of energy are released.

And the deuterium nuclei produced by the reaction eventually converge into helium nuclei.

The same helium nuclei can also be fused, fusing carbon and other heavier elements. But the effect of the upheaval is far less than that of hydrogen.

The above sounds easy, but why is there no nuclear fusion on Earth?

Just by knocking two nuclei together, you can easily fuse, because there is a strong force in the nucleus, which is very strong, but it can only work in the nucleus, like a tiger in a cage.

To light up two tigers touching each other, you need to break the cage between them, what is the cage? Electromagnetic forces, nuclei are both positively charged, and it takes a lot of energy to get them close to overcome the electromagnetic force. Although the magnitude of the electromagnetic force is negligible compared to the strong force, its total range is infinite, so to overcome the electromagnetic force, the nucleus needs to have a very high temperature (that is, the speed of movement), and only on stars can there be such a temperature that allows the nucleus to overcome the electromagnetic force to fuse.

Stars are not just hydrogen and helium, there are also small amounts of other elements, and our sun is. Heavy elements tend to sink into the core, and the heavier the core of the star, the hotter the core, the richer the products of nuclear fusion, and naturally a large number of heavy elements will be produced to participate in nuclear reactions.

Upstairs is incomplete Nuclear fusion forms a lot of new elements, according to h he li and so on can be carried out all the way to iron, the elements after iron in the periodic table cannot be formed by nuclear fusion in stars, they all come from the moment of supernova explosion.

The center of the Milky Way is said to be the Great Black Hole, around which the solar system (on the edge of the Milky Way) revolves and then travels through the spiral arms, sometimes outside them, once every 100 million years.

It is okay for stars to revolve around the star, as in binary star systems, some revolve around each other, and some have companion stars revolve around the host star.

The central part of the Milky Way galaxy is called the Milky Way, which is currently composed of a large group of stars and three black holes. It is by their gravitational pull that the sun revolves around the Milky Way.

Everything in the world is in motion, and although the star seems to be constant in the sky, it actually has its own motion. Because different stars move at different speeds and directions, their relative positions in the sky change from one to another, and this change is called the star's self. Among the stars of the day, including those faint stars that are invisible to the naked eye, Barnard's star is the fastest on its own, reaching the arc second per year (1 arc second is 1/3600th of a degree on the circumference).

Stars in general, on their own, are much smaller, the vast majority of which are less than 1 arc second.

The size of the star does not reflect the speed at which the star is actually moving. At the same speed, the distance looks slow, and the distance looks fast. Because Barnard is so close to us, less than 6 light-years, the true velocity is only 88 km/s.

The self-possession of a star only reflects the movement of the star perpendicular to the direction of our line of sight, which is called the tangential velocity. Stars are also moving in the direction of our line of sight, and this speed of motion is called radial velocity. The radial velocity of Barnard's star is - 108 km s (negative radial velocity indicates approaching us, while positive radial velocity indicates leaving us).

The velocity of a star in space should be the combined velocity of tangential velocity and radial velocity, and for Barnard's star it is 139 km s.

The spatial motion of the above-mentioned stars consists of three parts. The first is the circular motion of the star around the center of the Milky Way, which is a reflection of the Milky Way's rotation. The second is the reflection of the Sun's participation in the rotational motion of the Milky Way.

After deducting the reflection of these two motions, it is really the motion of the star itself, which is called the motion of the star.

Stars use nuclear fusion to transform light elements into heavy elements in the process of releasing energy to emit light and exothermy, of which hydrogen is the most energy released, with the increase of atomic mass, the worse the fusion efficiency, and iron is a critical point, when fusing iron, the energy required is balanced with the energy released, and the fusion of elements after iron has to absorb energy, so that the star will perish.

In addition, not only radioactive elements will decay, but all elements will decay, but you can't estimate the time it takes with time on earth, heavy elements decay just the opposite, to release energy, the heavier the element, the more energy is released, and iron is a critical point.

So whether it's fusion or fission, the trend is to iron, and iron has a very special place in the periodic table.

Because the mass of iron is large, the fusion of iron in the star cannot continue, so the star "dies" without energy.

Because iron can't release energy for nuclear fusion, it needs energy, and stars need to release energy to produce outward radiation pressure to resist centripetal gravity, and iron fusion can't provide energy, so there is no strength to resist gravity, so the outer matter falls rapidly to the center under the action of gravity, and when it encounters a neutron star formed by the contraction of the center, a supernova explosion occurs, and the star comes to an end.

The star is indeed close to death. At first, the main element in the star was hydrogen, and four hydrogen atoms fused into one helium atom at extremely high temperature and pressure, which is the first stage of the star; Later, when hydrogen runs out, the star enters the second stage, helium fuses into heavier carbon, and the star becomes a red giant; When helium runs out, carbon and oxygen fuse into silicon, a process that is even more intense; Eventually, silicon began to fuse into iron, which was a supernova explosion, and the star completed its life.

Stars with the same mass (or small dots) as the Sun: nebulae Protostars Main sequence stars Red giants Planetary nebulae White dwarfs Black dwarfs Stars with a mass greater than the Sun: Nebula Protostars Main sequence stars Bright stars Red giants Supernovae Neutron stars or black holes (supermassive black holes depending on mass).

Stars with masses equal to the Sun: nebulae, main-sequence stars, red giants, planetary nebulae, white dwarfs, black dwarfs or planetary nebulae, interstellar gas.

Stars with a mass equivalent to 8 times that of the Sun: nebulae, extremely bright main-sequence stars, red supergiants or blue supergiants, supernova explosions, neutron stars, or black holes.

Nebulae – star formation – stars – red giants – supernovae – black holes.

The Sun – Red Giant – White Dwarf – "Goes Out".

Big stars – superred giants – supernovae – neutron stars.

Black holes (more massive stars).

Black holes - nebulae - quasars - stars See The Dialectic of Nature of the Heart.

The less massive the star, the less violently the star will have a longer lifespan.

The lifetime of a star is inversely proportional to the magnitude of its mass. The more massive a star is, the exponential decreasing lifetime of its star. For example, a star as heavy as 10 Sun has a lifespan of 10 million years, while a star that is only twice as heavy as the Sun has a lifespan of 2 trillion years.

The greater the mass, the faster it burns in order to resist its own gravity, so the shorter the lifespan.

Theoretically, stars.

Copying should be around the star strike cluster or star.

The center of the system revolves, the center of the BAI star cluster can be a giant star or a black hole, and the center of the galaxy is a giant black hole.

Take the Sun as an example: the Sun revolves around the center of the Milky Way, and it is generally believed that the center of the Milky Way is in the constellation Sagittarius, which is called Sagittarius. However, some sources suggest that Sagittarius is a giant black hole; There are also sources that believe that Sagittarius is only the center of the star cluster where the Sun is located, and that it is a binary star system, one of which is a black hole.

Planets do not all revolve around stars, such as the moon and the earth, it is not who revolves around whom, they rely on gravity to revolve around a common center, but this center is closer to the one with the most mass! All stars are in motion, and the universe has no center!

The atomic number is equal to the number of protons in the nucleus, so the atomic number of HE is higher than that of H, and the HE atom has two extranuclear electrons, and the H atom has only one, of course, the radius of the H atom is small.

H has a small atomic radius, and HE is a noble gas.

Atomic configuration, larger in size.

h They are in the same period, from left to right, the radius decreases at once, and the radius of the same main group increases from top to bottom.