Why Does The North Star Appear To Be Fixed?

  Given that you are living in the northern hemisphere of the planet like me, you have probably noticed one particular star, which happen to be pointing towards the north, always remaining stationary no matter the season or what time at night you look at it. This star is Polaris, the North Star. Why does this star always point towards north? Why does it appear to be fixed in the sky? The answer is fairly simple actually. Polaris is positioned in such a way that the line of Earth’s axis of rotation projected to the space is very close to it. As it is the only bright(ish) star in the vicinity of the line of rotation of earth, it appears to be fixed in the sky while the other stars appear to be moving in the opposite direction of rotation of the Earth. What Happens When You Go Towards The South? If you were to look up at the sky at the North Pole, you’ll see Polaris directly overhead while the other stars move around it throughout the night. As you start to move away from the Pole,

Can Things Explode In Space?

Space explosion, explosion in space

Science fiction movies have made us believe that explosions in space are big and cool! The scenes are engrained in our brains. But can things really explode in space? Is it really like as it is portrayed in cinema?
Can things explode in space? Cinematic explosions couldn’t be more farther from the truth. In reality, the explosions in space are really small, if they occur. Space is a vacuum and only way things can explode is when there’s a source of oxygen nearby so there’s a slight chance of an explosion in spaceships but it’s not as glorious as you think. No sounds as well. The explosions, however, are as violent as the cinemas if not more even if it doesn't seem so. How? Keep reading till the end to find out!

WHAT IS AN EXPLOSION?
Explosion

An explosion is defined as a sudden oxidation or decomposition reaction that occurs when temperature, pressure or both increases. Every explosion releases some kind of energy. It could be heat, motion, sound, radiation or all of them at once. Many explosions are accompanied by a fireball. There are three vitals elements for fire- heat, fuel and oxygen. It is quite evident now why explosions cannot happen in space as there is a lack of oxygen.

HOW DO EXPLOSIONS WORK ON EARTH?

When a bomb is detonated on earth, it’s not the flying shrapnel (fragments of detonated bomb) that causes the most destruction nor is it the hot gas. It’s the shockwave. Its energy moves out similar to a sound wave but it moves much faster than sound. The molecules also get pressed together which creates a huge difference in pressure. This causes violent winds stronger than the most destructive hurricanes. Whatever is in its path gets destroyed.
Explosion

WHAT WOULD AN EXPLOSION LOOK LIKE IN SPACE?

Space is a vacuum. The gravitational attraction of massive objects pulls the gas molecules towards itself leaving the space between these massive objects virtually empty. Due to this a basic ingredient for fire, oxygen, is not available. So there would be no huge fireballs in space.
Spacecraft
If the spacecraft happen to carry any liquid oxygen which they do most times, it would be enough to catch fire producing a brief  burst of light. However, it isn’t as dramatic as you think. After a very short time, all the oxygen in the spacecraft would be used up and the fire would go out pretty quickly.
Another important absence of a dramatic explosion is the lack of sound. There are no particles in space to carry the sound waves produced by the explosion. There are as many as 1021 (1 followed by 21 zeros) gas molecules inside a bowl on earth while the same bowl in outer space would have about 300 particles. So chances of hearing are slim. The only way you can hear the explosion is if you’re standing beside the explosion but i bet you wouldn’t want to do that. If you did, you won’t be able to tell us the tale!
Space shrapnel
The shockwave that makes explosions so much more dangerous on earth would also not be present again due to absence of particles in space. The explosion would just release shrapnel moving at high velocity in all direction from the centre of the blast and hot gas and radiation. The shrapnel would continue moving at high velocity due to absence of friction and other resistive forces until it hits something. This high speed shrapnel makes the explosion so much more dangerous as one hit is enough to destroy anything (artificial).  

WHAT KIND OF EXPLOSIONS CAN HAPPEN IN SPACE?

Chemical explosions can happen in space as they occur by breaking of the bonds of chemical substances but they are not as same as physical ones. Also you definitely cannot hear anything and the explosions will differ from the ones in movies.
Radioactive, Nuclear fisson
Nuclear fission can definitely occur in space. They don’t require oxygen and they produce an intense amount of energy of heat and light in the process where the nuclei of atoms split. They would look like nuclear explosions on earth without the shockwave and the radiation would spread with every square unit area eventually making it harmless at a distance from the explosion.
For a brief period, nuclear weapons were successfully tested in space. Most famous is the Starfish Prime explosion in 1962 where the nuclear detonation occurred at about 400 km above the surface of the earth. This produced intense auroras which were visible from the pacific region remaining for as long as 7 minutes. These tests were successful but the Partial Test Ban Treaty banned above ground nuclear tests in 1963.
Supernova
Some natural explosions do occur in space. Some catastrophic events such as supernovae explosion and merging of black holes are examples. Nuclear fusions in the stars are also explosions in space. Explosions on earth are quite feeble in comparison. They could wipe us out if we were in its range. 50-100 light years from a supernova is the safe zone meaning it could wipe us along with the whole solar system if it were to happen nearby?

CONCLUSION

Explosions in space cannot occur as portrayed by Hollywood due to the absence of oxygen. This limits the destructive capability as it cannot produce shockwaves. Also sound cannot be heard. The explosions that do occur are brief burst of lights which finishes once the oxygen in the spaceship is all burnt up. Other explosions include chemical explosions and nuclear reactions. Catastrophic natural explosions in space dwarves any other explosions produced by humans making our weapons of mass destruction insignificant.
Thank you for reading and keep on being curious!
Let me know your thoughts in the comment section below.

Comments