#2 Secret Universes: An Unprecedented Journey into Neighboring Solar Systems | Space Documentary

🌍 Is there, among the countless stars that illuminate our night sky with a thousand lights, stellar systems identical to ours? Who has never asked himself this question by plunging his gaze into the depths of a starry night. To this day, no one is willing to answer this mystery. However, astronomers who have been interested in this question since antiquity have never ceased to track down, observe and then list each of the stars discovered in the course of their work, even the most insignificant. Although they do not have a reliable answer to share with us concerning the number of stars around us, they are now able to refine their estimates. The latest technological advances, ever more powerful, now allow scientists to refine their figures, and these, as you can imagine, are staggering. Some estimate that there could be over 200 million trillion.



🔥 As a reminder, the videos are published on SUNDAYS at 6:00 PM.


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💥 OUR NEIGHBORING STAR SYSTEMS:
- For starters, what is a star system?
At first glance, when we look at stars, we might think that they are all independent of each other. But this is not the case. If some stars are isolated, evolving without interactions with their distant neighbors, others are linked by gravitational attraction. When a small number of stars, thus linked, orbit around each other, we speak of a stellar system, each star being a component. It happens that some star systems are falsely named as such, being composed of a single star, it has a planetary system in its orbit.

The discovery of these stars also influences their name. We speak of visual or astrometric star systems when they are discovered through their apparent movements in the sky. When they are detected according to the variation of their brightness, they are then called eclipsing star systems. Finally, when they are characterized by their spectrum, they are called spectroscopic star systems.

A stellar system of two stars can have different names such as a binary system, a binary star, or a double star. This is notably the case of Sirius, the most sparkling star in our night sky.

Multiple star systems, with more than two stars, are diverse. A triple, trinary or ternary star system contains three stars. A quadruple or quaternary system contains four. We can continue with quintuple, sextuple, septuple systems for respectively five, six or seven stars, and so on. When a system contains a hundred stars, or even many more, it falls into the category of star clusters, or even galaxies.

But let's leave this theoretical part now, and let's focus on the closest systems, located in our galactic neighborhood.

Proxima Centauri, a stellar and planetary system which also answers to the name of Alpha Centauri C. You will understand later on where this last name comes from. We are in the constellation of Centauri, only 4.2 light years from Earth and therefore still in our beautiful and luminous Milky Way. The luminous object you have before you is a red dwarf. These are very common in our Galaxy. They represent nearly 80% of the stars in the Milky Way. The apparent magnitude of Proxima Centauri, which is equal to 11.05, does not place it in the category of the brightest stars, the most radiant stars being of first magnitude. In fact, 85% of the energy it emits is not visible to our eyes, being mainly in the infrared wavelengths. To the naked eye, its luminosity in visible light is almost 650 times less than that of our Sun. Proxima Centauri is therefore of spectral type M5, which explains why it was only discovered in 1915.

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🎬 On the program today:
- 00:00 - Introduction
- 04:05 - The different types of star systems
- 06:43 - Proxima Centauri
- 12:40 - Alpha Centauri A and Alpha Centauri B
- 18:34 - Barnard's Star
- 23:40 - Luhman...