A red dwarf is a type of star which was never able to gather enough energy or mass to form into a normal-sized star or massive star. These stars are the most common stars in our universe and the smallest, just larger than the size of gas giants like Jupiter. This small size enables them to live the longest, as they burn slowly over trillions of years. That is precisely why they are the best type of star for the survival of life in the universe.

On the other hand, the habitable zone of a red dwarf is very small. To be in the habitable zone of a red dwarf, a planet would need to be about 75 times closer to the aforementioned star than mercury is to our sun.

But, this is detrimental for the planet as this tidally locks  the planet. This means that the planet will not rotate the way most planets do. One side would be locked in perpetual, blazing day and the other in a cold, endless night. A small fraction of the region between the two zones could have a day-night cycle, liquid water and could possibly support life.

Another problem with red dwarfs is that they have incredibly large solar flares. Our sun and all stars beget solar flares, but, due to the closeness of the planet to the red dwarf, these solar flares could have cataclysmic effects on the aforementioned planet.

The death of a red dwarf is a lethargic process as the star slowly burns its supply of hydrogen, fusing it into helium. When a red dwarf, or any star for that matter, runs out of supply of hydrogen, it fuses helium into carbon and carbon into heavier elements. For heavier stars, this process is gradual, but in a red dwarf, this sparks a huge change as they start to radiate blue and burn hotter.

In all stars, there exists a balance between the star’s mass, pertaining to gravity, and its heat. When this balance is disturbed, the stars die. A normal-sized like our sun will slowly shed its outer layers in an exquisite planetary nebula, leaving behind a tiny, yet dense white dwarf whereas a supermassive star will go out in a bang, literally, in the form of a supernova. On the other hand, a red dwarf will, quite peacefully, transform into a white dwarf.

A white dwarf is a very dense remnant of a star, with lots of reserved heat, which it releases over trillions upon trillions of years.

Now, not even white dwarfs can last forever, but that’s a topic for another blog.

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If you would like to look into this topic more, I highly suggest the YouTube channel Kurzgesagt -In a Nutshell. Here’s their video about red dwarfs:

The first ever image of a black hole was released very recently on the 10th of April. The black hole shown on this image is a supermassive black 38 billion times the mass of our Sun at the centre of the M87 galaxy. The sheer impact of this image on the world has to be something everyone alive today knows.

The reason that being near a black hole is so difficult is due to its massive gravity. Black holes are black because of the fact that their gravity exceeds the speed of light This means that not even light can escape from a black hole’s event horizon, i.e, the point after which nothing can escape the black hole, a point of no return. Due to this stupendous force of gravity, space-time itself is warped around a black hole. As we know, gravity is the bending of space around a massive body. To interpret this in easier methods, if space is a soft comforter, then Earth would be a small, lightweight ball creating a slight depression in the comforter; the Sun would be a heavier ball with a deeper depression and a black hole would be the equivalent of a small, highly dense metal ball which creates a depression exponentially larger than the one created by our ‘Sun’. This bending of space-time becomes even more ludicrous when you realise the fact that if you were to fall towards a black hole, time would slow down for you and for anyone watching you from outside, you would speed up.

Now, this image may not mean anything to a lot of people, so I’ll do my best to explain it. The black part at the centre of this image is the event horizon of a black hole. The part coloured a red-orange around the black hole is the accretion disc. The accretion disk is a disk of matter which revolves around the black hole at near light-speed. The minimum distance from the singularity at which is 3 Schwarzschild radii, i.e, 3 times the radius of the event horizon. However, you may also notice an evidently brighter section closer to the event horizon. This region is called the proton sphere, and, well, it is what it sounds like- a sphere of protons orbiting the black hole. Light, unlike matter, has no mass. So, it it possible for light to orbit the black hole much closer, at 1.5 Schwarzschild radii, to b exact. Now, I’m no astrophysicist, but I did my best to explain the image of the first black hole to you.

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Here’s a video that explains this concept a little more in depth: