Page 6 - Geografie_Geography_Terra_O_Planeta_A_Universului

What happens inside the stars?

Well, the star is a oven that once ignited it
burns, as a rule, several billion years. Let’s look at
the source of its energy under a microscope!
At temperatures of several million degrees
Celsius, two hydrogen atoms join together, it
means that they fuse nuclear, resulting in a helium
atom. By this reaction, mass is lost, but a lot of
energy is obtained. Does this mean that stars are
constantly losing weight? Let’s check and put our
Sun on the scales! Here they are! It loses 5 tons Nuclear fusion
every second, but is still large enough to provide us with light and heat for another 5 billion years. If our
species is intelligent enough not to self-destruct, we will surely have enough time to reach other stars.

Journey among the stars

Milky Way
If we exclude the Sun, the closest star to us Along with Andromeda and the Milky Way,
is Proxima-Centauri. Light takes better than 4 The Universe has hundreds or perhaps trillions of
years to get from there to the Earth. But our galaxy, galaxies. We discovered all this with the help of the
called Milky Way (“Calea Lactee”) to which The Space Telescope Hubble released in 1990.
Sun and Proxima Centauri belong, is very large. It
has hundreds of billions of stars and it takes nearly
200,000 years for light to cross it. This means that
a ray of light entering our galaxy when the first
homo sapiens appeared has not yet been able to
travel through the entire galaxy. It will take them
more than 2,500,000 light-years to reach the nearest
galaxy named Andromeda.