Stars are massive celestial bodies made mainly of hydrogen and helium that produce light and heat inside their cores from the churning nuclear forges. Apart from our sun, all light-years from Earth are the points of light we see in the sky.
Facts About Stars
These are the building blocks of galaxies, billions of which exist in the universe. How many stars actually exist is difficult to say, but astronomers believe that there are about 300 billion in our Milky Way galaxy alone. The Sun is the closest star to Earth.
1. Stars Aren’t Next to Each Other
Binary star systems aside, most stars are sitting there in either direction, totally bored, with no one around for massive distances. Our sun is no exception- Proxima Centauri, the nearest star in our fastest spacecraft, is 4.24 light-years away, or 70,000 years away. And if the sun was a New York ping pong ball 4 cm in diameter, the nearest star is another 1,153 km (743mi) ping pong ball in Atlanta.
2. The Sun is the Closest Star
It’s pretty amazing to think that the average example of all the stars in the Universe is our own Sun, located a mere 150 million km away. Our own Sun is listed in the principal sequence process of its existence as a G2 yellow dwarf star.
For 4.5 billion years, the Sun has gladly converted hydrogen to helium at its core, and will likely continue to do so for another 7 + billion years. When our Sun runs out of fuel it’ll become a red giant, bloating up its current size several times. The Sun will consume Mercury, Venus and possibly even Earth as it expands.
3. Stars Are in Perfect Balance
You may not know that but stars are in constant conflict with each other. The combined gravity of all a star ‘s mass draws it inwards. If nothing had prevented it, the star would only continue to fall for millions of years before it was its smallest possible size; maybe as a neutron star.
But there is a pressure which pushes back against the star’s gravitational collapse: light. At the core of a star, nuclear fusion produces a huge amount of energy. The photons are moving outward as they make their way to the surface from within the star; a path that can take 100,000 years. As stars become larger, they grow outwards to red giants. And when the light pressure runs out, they break into white dwarfs.
4. Stars are Made up of Same Things
All the stars start from cold molecular hydrogen clouds which collapse gravitationally. As they collapse in the cloud, it fragments into many pieces that will begin to form individual stars. The material gathers into a ball that continues to collapse under its own gravity until nuclear fusion can be ignited at its core.
After the Big Bang, this initial gas was formed and is now around 74 per cent hydrogen and 25 per cent helium. Through the passage of time, stars transform some of their hydrogens into helium. Which is why our ratio to the Sun is something like 70% hydrogen and 29% helium. But with other trace elements, all-stars begin with 3/4 hydrogen and 1/4 helium.
5. Stars Come in Multiples
It may sound like all the stars are out there, all alone, but many come in pairs. Those are binary stars which orbit a common centre of gravity by two stars. And there are other three, four and even more star systems out there. Just think of the stunning sunrises you ‘d witness waking up to a four-star world around you.
6. Stars Are far Away
It’s incredible to consider the vast distances involved, with so many stars out there. Proxima Centauri is the nearest star to Earth, located 4.2 light-years away. In other words, the journey from Earth takes more than 4 years to complete for light itself.
If you were trying to hitch a ride on Earth’s fastest spaceship ever launched, it would still take you over 70,000 years to get there from here. It’s just not feasible to travel between stars right now.
7. Most of the Stars are Red Dwarfs
If you could bring all the stars together and place them in piles, the biggest pile will be the red dwarfs. There are stars with less than fifty per cent of the Sun’s mass. Red dwarfs can also be as tiny as 7.5 per cent the mass of the Sun.
The star doesn’t have the gravitational pressure below that point to raise the temperature inside its core to start nuclear fusion. These are known as brown dwarfs, or failed stars. Red dwarfs burn with much less than 1/10,000th the energy of The Sun and will sip off at their fuel for 10 trillion years until they run out of hydrogen.
8. Saturn would be Engulfed by the Biggest Stars
Speaking of red giants, or red supergiants in this case, there are a few monster stars out there that really make our Sun look small. The star Betelgeuse in constellation Orion is a common red supergiant.
It has about twenty times the Sun ‘s mass but it’s a thousand times bigger. However, this is nothing. The Monster VY Canis Majoris is the largest known star. This star is thought to be 1,800 times the Sun ‘s size; it will engulf the orbit of the planet Saturn.
9. Most of the Massive Stars Live the Shortest
As mentioned above, before finally running out, the low mass red dwarf stars can sip away at their fuel for 10 trillion years. Okay, the opposite is true of the most massive stars that we know.
Such giants may have as many as 150 times the Sun ‘s mass, and emit a furious amount of energy. For example, Eta Carinae, located about 8,000 light-years away, is one of the most massive stars we know of. It is thought that this star has 150 solar masses, and puts out 4 million times more energy.
Although our own Sun has been burning away peacefully for billions of years and will continue to go for billions more, Eta Carinae has probably been around for just a few million years. And astronomers expect Eta Carinae to detonate at any time now as a supernova.
Whenever it does go off, after the Sun the Moon it will become the brightest object in the sky. It would be so bright that during the day, you could see it, and read on its light at night.
10. Number of Stars in Space
You may be shocked to hear that our galaxy contains 200-400 billion stars. Every one of them is a different island in space, presumably with planets, and some may even have life. But again, the Universe could have as many as 500 billion galaxies, and each of them could have as many or more stars as the Milky Way. Multiply those two numbers together and you can see that the Galaxy may have as many as 2 x 1023 stars. This is around 200,000,000,000,000,000,000,000.
11. UY Scuti is the Largest star by Radius
Another way to describe the size of a star is by its diameter, which is usually written in terms of the Sun’s radius. Astronomers theorize that the largest solar radii that a star can be are just under 2,000. There are a few stars, including one called UY Scuti, that exceed that scale. It is a red supergiant measuring approximately 1,708 solar radii (about 2,4 billion kilometres).
12. Some Stars Disappear Without a Trace
With such a gigantic shape and structure, its an understandable belief that it would always be known if and when a star vanishes, but stars do disappear with no trace at all.
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