What is a Black Hole?

Introduction

There have been several fascinating discoveries in the field of Physics and one of them is the existence of Black Holes. A black hole is the remains of the core of a planet, who’s gravitational field strength is so enormous that even light cannot escape. That’s how it gets its name i.e., black hole, as light is not reflected from a black hole and we cannot see it.

Do you wonder how do we know that they exist when we cannot see them? Let’s find out how we are able to recognise a black hole.

Creation of a Black Hole

There are billions of stars similar to our Sun in the universe who’s life cycle will come to an end at one point of time. Don’t worry, our sun is estimated to last for another 5 billion years, so we are safe (for now). The creation of a star begins as hydrogen atoms start nuclear fusion and become helium atoms. This reaction produces a lot of energy and heat, which is why our sun is so hot.

As more particles come together, a gravitational field is created and it pulls the particles together. The nuclear fusion tries to expand the particles and gravity tries to squash them. When these two forces are in balance, the star’s radius remains constant and the star is in the main sequence. Our sun is a main sequence star at the moment as its size is not changing and it produces constant heat. As the fuel (hydrogen) is running out, gravity takes over and particles will be squashed.

If the star is less than 5 times the size of our sun, it will become a red super giant and will soon die out to become a neutron star. If the size of the star is more than 10 times the size of the sun, as the fuel runs out, it will explode to become a Supernova. What remains after a Supernova is the super dense core of the planet. This core is called a black hole as it’s very dense. If planet gets very close to it, it will be sucked to the black hole and it will be destroyed.

Existence of Black Hole

Answering our initial question, while we cannot see black holes directly as light cannot be reflected from them but we can surely observe the planets around a black hole. They travel around it and they get closer to the black hole. At some point, the planets or stars get so close to the black hole that they disappear. According to Stephen Hawking, when a planet is consumed by a black hole, radiation is released in the form of X-rays. These rays are called Hawking's Rays but they haven’t still been discovered.

Conclusion

Universe is full of mysteries, some of which are quite unimaginable. Black holes are one such mysteries that scientists are still trying to comprehend. Our collective understanding of black holes revolves around several assumptions and theories created about black holes still remain to be unravelled. We hope they are unravelled soon, making black holes a bit brighter to us.

My Top 5 Stationery Favourites - Connie Studies

Guest Post by Connie Studies

Hello! My name is Connie and I run the account @connie.studies on Instagram! I post about study tips and stationery pics to get you motivated to study! My dream is to get to Cambridge to study either philosophy or classics I hope you will follow me on this journey! Today I’m going to share with you my top 5 favourite stationery items for studying! Enjoy!

1. PENS

There are so many amazing pens on the market nowadays and it can be hard to choose which pen would be right for you! My personal favourites are the Muji 0.5 Black Gel Pen and the Pentel Energel 0.7. The Muji Gel Pen is great for if you have larger thinner letters but, it is prone to smudging especially when highlighting. The Pentel Energel is awesome for smooth consistent letters and has a much more comfortable grip.

The only thing is that it is quite thick and not too good for smaller letters and can be quite expensive. Despite my love for these pens, I do still love using the classic ballpoint pens for general note takings as you can highlight your notes straight after which saves a lot of time!

2. Highlighters

The highlighter industry I feel has really taken off over these past few years. Now, as you may know from my Instagram, I’m really into my pastel highlighters. One of my favourites are the Zebra Mildliners. These highlighters come in twenty different pastel colours and have a chisel tip as well as a fine highlighter tip! I really love these highlighters! They are really good for on the go as they are the same size as a pen but do wear out quite easily after continuous use.

My all-time favourite highlighter is the Stabilo Pastel Highlighters. What I really like is the fact that it comes in a range of different sizes I’m sure you will find one suited to your needs! The colours are really beautiful and I really wish they would bring out more pastel shades! I have heard a lot of people talk about the Pilot Frixion Pastel Erasable Highlighters so I have ordered them to give them a try (stay tuned to my story for my review on them!). I have also tried the Muji Highlighters with the window so you can see what you're highlighting. I do really like these highlighters but think they need to bring out more colours!

3. Brush Pens

In the brush pen category, there are few that I have found to be a good brush pen. My second favourite is the Tombow Fudenosuke Brush Pen. This pen is really great for doing titles and sub-headings in because it’s so thin. I prefer to use the hard tip rather than the soft tip because I do find it easier to do control. The only thing I find rather annoying about the Tombow is, after a while, the nib wears away quite easily and splits.

My all-time favourite brush pen is the Pentel Fude Touch Brush Pen! It’s so nice to hold and has a really nice nib. I would really recommend this pen, it’s also a bit cheaper than the Tombow!

4. Erasers

My favourite erasers of all time are the Muji Erasers. I have the large eraser for use at home, and my small Muji Eraser is for school use. I do also love using the pushy eraser because it’s so precise and is really useful for smaller mistakes made in notes. My only problem with this eraser is that it does get dirty very easily and then smudges onto the next paper when you erase something else.

Another great alternative is the Milan Capsule Eraser! I have used one of these erasers for years in my school pencil case and I love that it doesn’t get anything else in your pencil case dirty because it is contained in a capsule! Another great thing about it is, it has a built-in pencil sharpener, which is very handy.

5. Notebooks

I have so many favourite notebooks that I love to use for my note-taking. My first favourite is the White Lines Notebook, I love the fact you can scan your notes on the app and also have a range of different sizes. I also really enjoy using the Leuchtturm 1917 notebooks for bullet journaling and note-taking. These come in a variety of different colours and are just generally a really nice notebook!

I hoped this little stationery favourites post helped you when choosing your writing utensils for school and studying.

Thank you for reading!

Xx Connie Studies

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Recommendations:

Muji 0.5 Black Gel Pen

Pentel Energel 0.7

Zebra Mildliners

Stabilo Pastel Highlighters

Pilot Frixion Pastel Erasable Highlighters

Tombow Fudenosuke Brush Pen

Pentel Fude Touch Brush Pen

Muji Erasers

Milan Capsule Eraser

White Lines Notebook

Leuchtturm 1917

What is (the) Time?

Time is one of the strangest things we can talk about. It is a simple concept that kids can understand at an early age but the concept of time is hard to explain in words. So, let’s spend some time talking about time.

Describing Time..

Time can be observed in nature only when changes occur. We look at the sky and we see clouds moving, meaning that time is passing. We sleep one-third of the day but that third might feel like seconds because we don’t see any changes.

When we are in a classroom and the subject feels boring, time doesn’t seem to move at all. However, when you are in a classroom where you like learning new things, time flies. How is that possible?

Einstein has said that if a man spends the same amount of time being with a beautiful woman and sitting on a bed full of thorns, the first would seem like seconds and the latter would seem like an eternity.

Einstein and relativity

Einstein was the first one to prove that time isn’t a constant that doesn’t change like we assume even today. Time is a property that changes depending on where we are. Let us explain this in simple words.

Einstein said that mass can make time and light bend. The bigger the mass the higher the curvature of time. On Earth, for example, we have a constant time. So, let’s consider two twin brothers. One will stay on Earth and the other on the Moon and they meet after 50 years. The brother that lived on the Moon will look much older than his brother on Earth. Earth being heavier than the Moon, time passes slower around a heavier object than the lighter object. So, the time on the Moon passes much faster than on Earth.

There is No Present...Just Past and Future

It might sound strange, but let us break this down for you. If we ask you the exact time now, you might say 17:15 and 25 seconds. But by the time we hear the time you just said, it would already be 17:15 and 26 seconds. So, the time you just told us is already past by 1 second.

Still not convinced? Alright then, imagine you are on a train moving at a constant speed and are on the phone with us. If we ask for your exact position, by the time you give us a position, you will have moved past that position because the train is in constant motion. Hence, you would never be able to give us your exact position as long as the train is moving. So, the moving train is a perfect way to explain time.

Conclusion

As you can imagine, science has discovered certain properties of time but it is still unable to entirely explain Time as a concept. Thermodynamics can explain time as hotter objects transferring heat to colder objects. In fewer words, it is the rate of change that defines time as per thermodynamics.

What we know about time is that it cannot be stopped, except in a black hole. Time is relative to the rate of change of the nature that surrounds us and finally, time will finish for us on one or the other day, so enjoy it!