Remember, the important thing is not to stop questioning – Albert Einstein


I dedicate one week of every month’s to post about questions taken from Quora. Here goes this month’s bunch.

  1. Where exactly is our solar system located?

If you examine our Milky Way graphical upper view, it sort of looks like an octopus’s top view but with spiral shaped arms.

These arms illuminate interstellar dust and gas. Each arm, named as Perseus Arm, Sagittarius Arm, Centaurus Arm and Cygnus Arm and our solar system lies in the Orion Spur which is a minor arm. It is located 26,000 light years from the center of the Milky Way Galaxy.

Here is NASA’s pictorial view:

  1. What happens if the Sun turns into a black hole?


Black Holes are usually formed when stars with greater mass collapses onto itself. This happens to the stars whose mass is 20 times greater than of our very own sun. So no, chances of our Sun turning into to black hole is unlikely.

  1. What are some cool facts about space that most people don’t know?

Space is filled with so many mysteries that fascinates people’s minds everyday. Here are some fascinating facts about our very own solar system:

  • Mercury, despite being the planet closest to Sun is still only the second hottest planet. Venus takes the first place.
  • Venus and Uranus are the planets that rotates in the opposite direction unlike Earth or the other planets in the Solar System. This phenomena is known as Retrograde rotation.
  • As many of you know, Earth was once to be in the center and other planets, including Sun was in its orbit.
  • Scientists have found pieces of Mars fallen to Earth – they were found within the meteorites violently ejected from Mars.
  • Jupiter finishes its lap around the Sun every 11.8 Earth years and Saturn finishes its lap every 29.4 Earth years. They are the fourth and fifth brightest objects in the solar system visible with the naked eye in the sky as stars.
  • Sun – also goes by its Latin name Sol, is a main-sequence of yellow dwarf star. It is 4.6 billion old. Its light takes 8 minutes to reach the Earth. Its temperature can reach up to 15 million degree Celsius. It is made up of hydrogen and helium. Once the hydrogen is exhausted, it will take 130 million years to burn the helium by which time, it would have expanded and engulfed Mercury, Venus and Earth as it becomes a red giant.
  1. If there are almost an infinite number of stars, why is the night sky black?

It’s obvious, the sun sets and hence the black sky. But wait, what about the stars that we see? They are bright but why not bright enough to lit up the sky. Well, scientists has two theories to explain this and it makes sense.

According to Olber’s Paradox, our universe isn’t infinite and is static. If the universe was infinite, the stars would have went on forever – in which case we would see a bright night sky. Since its limited, the light from the stars hasn’t had the time to reach us yet.

Now, the Doppler Effect – I love this one. The universe is expanding, galaxies and stars are moving away from us at a rapidly. So according to the theory, light from the moving stars/galaxies shifts from visible to invisible (ie, infrared and radio waves), making them disappear. Hence the black night sky.

P.S. Black night sky is also evidence that our Universe is expanding. Who needs telescope when you can see the expanding with your own eyes – just stare into the deep dark night sky. Its miraculous.  

Source: space-facts, wikipedia, theconversation

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