Evolution of the Universe and Search for Exoplanets

The Big Bang and the History of the Universe

1. Stage of Inflation: The super-compressed universe expanded during the Big Bang. At an enormous speed, the universe grew during the stage of inflation.
2. Formation of Matter: The universe was composed of subatomic particles and immense amounts of energy in the form of photons. When it cooled to a billion degrees, neutrons and protons formed.
3. The First Atoms: Some 300,000 years after the Big Bang, hydrogen and helium atoms formed in percentages similar to those found today.
4. The Power of the Universe: Charged particles (protons and electrons) interfered with photons. But once they combined with each other to form atoms, light could travel freely in the newly created space.
5. Formation of Stars and Galaxies: 400 million years after the Big Bang, slightly denser areas of space became centers of gravitational attraction. The universe became transparent, and cosmic background radiation appeared.
6. Dark Energy: Towards 9 billion years, galaxies began to travel at increasing speeds. It is believed the cause is a dark energy of unknown nature that acts against gravitational attraction.

The Doppler Effect

When an object is moving while radiating, its waves are distorted. If the source approaches, the wave is compressed, and if it recedes, the wave lengthens. Something similar happens with light waves from galaxies; a redshift is observed in the spectrometer (longer wavelength), which is why we know galaxies are moving away.

8 Exoplanets: The Big Surprise

The detection of exoplanets, a term referring to extrasolar planets, shows that planets can exist around the majority of stars like our Sun. Most detected exoplanets are giant planets; only in 2007 did we begin to detect what are called Super-Earths. It is believed these planets migrated from distant orbits.

Conditions for Life on Planets

1. Distance from the Star: On planets that are too close or too distant, the temperature does not permit the existence of liquid water.
2. Sufficient Gravity: If a planet is small like Mars, the gravity is not sufficient to retain the atmosphere; if the atmosphere is lost, the hydrosphere would evaporate.
3. A Molten Metallic Core: By rotating, the core generates a magnetic field that protects the planet from X-ray and gamma radiation from the star.
4. Lifespan of the Star: High-mass stars live much less time than less massive ones. Only solar-type stars (medium) and stars less massive than the Sun may function long enough for life to develop.
5. Presence of a Large Satellite: Thanks to its gravitational anchor, the tilt of the Earth's swivel axis has not changed significantly.
6. Existence of Giant Planets: Thanks to their strong gravitational attraction, they can divert asteroids, protecting other planets.
7. Location in the Milky Way: Being far from the galactic center, where supernova explosions emit radiation harmful to living beings.