Incredible Curiosities #2

Welcome to Incredible Curiosities #2, your source for the most amazing facts about the Universe, life and everything else there is.

1. The Sloan Great Wall

As the name says, the Sloan Great Wall is a humongous wall of galaxies, or a galactic filament. It was discovered in 2003, in Princeton University.

The wall measures incredible 1.38 billion light years (light year: the distance light travels in one year). Just to have an idea, the speed of light, commonly known as c, is 3 x 10^8 (the number one followed by eight zeroes)  meters per second, or 1080 trillion kilometers per hour. Such an enormous distance can’t even be imagined by human minds.

The Great wall is about 1 billion light - years away from Earth and is the sixth largest structure ever observed, occupying about 1/60 0f the visible universe.

2. There are about 10^29  stars in the universe

Have you ever looked to the sky and tried to count all the stars you could see, one by one? You certainly found it a hard task. But those were just the stars on Earth’s night sky. Imagine trying to count 10^29( the number one followed by 29 zeroes) of them!

Astronomers have estimated that this is the number of stars that exist in our universe. What is a pretty big number, indeed. But with about 10 trillion galaxies out there and each of them, supposedly, with 100 billion stars ( like the Milky Way), we can understand the reason for such a tremendous amount.

Having this fact in mind, it is difficult not to think of extraterrestrial life. There are many factors that can affect the chances of a planet to develop life, of course. But with so many stars out there, and most of them having planets, it is no problem to dream of having cosmic neighbors.

3. Rogue planets

Unlike most planets, rogue planets do not have a star to orbit. Yes: they float lonely through the emptiness of space, like orphans.

Solar systems’ formations are very violent, and not every planet that is created can have a “place” among the ones who will orbit their mother star. This is what happens with rogue planets: in their early lives, they were kept away from their star , and, away from their planetary system, they freezed on the outside.

There could be billions of them floating around in space, but we can say it for sure -- they are too hard to detect. Most of the planets are detected by measuring their influence on their stars, like little wobbles caused by the gravitational tug of the planets or the small dimming caused when planets stay between Earth and their star. Therefore, without a star, scientists rely on infrared and gravitational microlensing techniques; which are still not effective.  

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4. You get taller in space

On space, because of microgravity, the force pushing your spine down in considerably lessened. This causes the human spine to be straighten, what can make people “grow” up to 5 centimeters.

In fact, the astronaut Scott Kelly, who has just returned from his mission on the International Space Station, is now taller than his identical twin, Mark Kelly. If you want to know more about the one - year mission, click here.

5. In space, metal sticks together

Yes, this is true: in space metals fuse together! This is amazing, but why?

On Earth, because of its atmosphere, a very thin oxygen layer covers metals. This is why, down here, no metal will stick together. However, in space, there is no such layer. So, if you touch to piece of metal in the vacuum, their atoms will connect to each other and make the metals fuse. This phenomenon is called “cold welding”.

This can be an actual problem for astronauts. To prevent this, metal tools used outside of the space station need to be covered by plastic or other material that can prevent fusing.