Modern Physics

astronomical facts

The Universe is full of celestial bodies with the most diverse characteristics. How about knowing some of the most interesting astronomical facts about the cosmos?

Astronomy is one of the  most fascinating areas of physics. When studying it, we come across a large number of curiosities about the Universe. In this text, we will bring you some astronomical curiosities for you to glimpse a little better the greatness of studies involving astronomy.


The Sun is a 4.6 billion year old dwarf star . Alone, it has 99.8% of the mass of the entire Solar System (about 333,000 planets Earth), ensuring that the gravity on its surface reaches 274 m/s², about 27 times greater than terrestrial gravity. The average temperature of its surface is 5500ºC, while its core can reach an incredible 15 million degrees Celsius.

Due to the great temperature and pressure in its core, the Sun is able to fuse hydrogen atoms into helium atoms , emitting energy in the form of electromagnetic waves . Despite the impressive numbers, our Sun is far from the biggest star in the universe compared to stars like VY Canis Majoris , whose diameter is around 2000 Suns.


Neutrinos are extremely light particles – hundreds of billions of times lighter than electrons – and neutral electrically. They only interact with the rest of matter through gravity and the weak nuclear force . They are produced in nuclear reactions such as those that occur in the cores of stars and in the reactors of nuclear power plants.

Because they are extremely small and poorly interacting, neutrinos can pass through even a rod of lead a few light-years long without colliding with any atom. Due to its proximity, the Sun is the largest source of neutrinos on Earth, guaranteeing a flux of 6.4.10 6 neutrinos/cm 2 /s, that is, every 1 second, at least six million solar neutrinos cross an equivalent area to one of your nails. An estimate made by astrophysicists in 2012 indicates that about 13% of the mass of the universe can be attributed to neutrinos.

Stars are black bodies

In physics, a portion of matter capable of absorbing all incident radiation is called a blackbody: no part of the radiation is reflected or transmitted through it The same is true for the stars. Despite producing a lot of radiation, both visible and non-visible, all electromagnetic waves that fall on them are totally absorbed. So if a star stopped emitting light, its surface would be perfectly black .

“Countless” stars

It is estimated that our galaxy has between 200 and 400 billion stars and that, in the Universe, there are hundreds of galaxies, resulting in a number of at least 10 sextillion stars. However, from Earth, under the best possible conditions, only about 8500 stars are visible to the naked eye.

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