Nuclear Fusion Inside Stars / Fission (Nuclear bombs)

Stars are dense, highly pressurized and extremely hot objects. In these extreme environments, plasma is formed (a state of matter after 'gas') where all the particles get 'unbound' in a way and merge into a singular chargeless fluid.

In this chargeless fluid, as all the particles are unbound and zip around at extremely high speeds, hence many nuclei collide and combine to make a new heavier element. This process releases an extenuatingly large amount of energy. The process was used to make the H-Bomb (many times more powerful than the A-bomb released on Hiroshima and Nagasaki). Essentially nuclei in a plasma state combine and create new nuclei and hence new elements and this process releases energy.

Hence in stars, due to the large amounts of pressure and heat at the cores, nuclear fusion takes place which creates new elements. Our sun in fact constantly fuses hydrogen into helium. However what's really fascinating is the fact that fusion stops at iron. There is a 'binding energy' that is needed to fuse nuclei and iron actually has the greatest binding energy despite not having the greatest molar mass. Hence fusing beyond iron is impossible.

Now moving onto nuclear fission. As some of you may know, isotopes decay through alpha, beta, and gamma radiation and do this based on their half-life. Technitium-99 a common medical isotope decays and has a half-life of 6 hours (extremely short). Alpha and beta radiation both cause a change in the element while gamma does not affect the original element. (Beta decay releases an electron and alpha decay releases a helium nucleus). Hence some scientists started thinking about atoms splitting into constituent elements aka nuclear fission. 

What basically happens is that uranium 235 or plutonium 239 are hit with a neutron beam or with a neutron. The new isotope now undergoes the process of fission and splits into two separate atoms. At this point, three more neutrons are released. If the uranium was in a pile then the new neutrons would irrigate the other uranium and a chain reaction would begin. Each 'fission' of uranium would release 2.5MJ of energy which is well.... a lot. A ton of this uranium would release that much more energy. Hence this chain reaction is what is used in the A-bomb as the large amount of energy/radiation causes the explosion and after-effects.

The missing antimatter problem

Some of you may have heard of the "missing antimatter problem" and in this post, I want to go into detail on what it is and what it means.

Starting off, currently there is way more matter than antimatter. Most things ranging from our books to large stellar bodies all consist of matter while there is very less antimatter. However, the big bang should have released an equal amount of matter and antimatter. Hence scientists are trying to find out the cause of this disparity.



To give a brief overview of what antimatter is, antimatter particles share the same mass as matter particles however they have opposite charges ie. a positive positron (antielectron) is simply the opposite of a negatively charged electron. When matter and antimatter come into contact, they both immediately annihilate and release energy usually in the form of gamma rays



Scientists recently were able to create and analyze an antihydrogen to a significant degree of precision and what's truly fascinating is the lack of difference between the two ie. both the hydrogen atom and the antihydrogen atom had no significant differences.

Currently, there is no explanation for this disparity however one theory has gained some traction. Due to the near infinite volume of the universe, we barely know anything about it. Hence it's not a stretch to say just like matter has formed galaxies, there also might be antimatter galaxies somewhere far in the universe. This is only speculation though as there is no real proof or alternatives.



I'll make sure to keep updating if something interesting is found.

Until then,
Adieu

How we discovered that the universe is expanding

To understand the acceleration of the expansion of the universe, we first have to understand what redshifting is and to understand redshifting we have to understand some basic information about the wave-particle duality of light.

As most physics students know, light has wave and particle-like characteristics and hence has a wavelength and frequency. In simple terms, scientists measure the light from a 1a supernova. However, due to the universe expanding, the light redshifts and scientists can calculate the redshift to figure out the expansion of the universe.

The idea of redshift is based on the fact that if light is attempting to reach somewhere, but the place is moving away at an extremely fast pace. Then light's wavelength increases and hence the colour turns red (visible light spectrum)




Hence while observing light from distant stars, scientists observed that the light was undergoing 'red shifting' and found out that the red shifting was increasing at an accelerated rate and hence the only way for this to happen is if space and hence the universe were to be expanding.

Now that we've gone through the how, let's go through the why. Currently this expansion of the universe is considered to be there due to 'dark energy' which is well...... we don't know. What we do know however is that something is causing this expansion and we have hence coined this something as dark energy. The existence of dark energy and expansion of the universe have led to some scenarios of the future of the universe but I'll go through that in another blog post.

Signing out,
Mehul.

White Holes / Kerr Black Holes / Multiverse Penrose theory Presentation

Hi guys,

Below is a link to my presentation on white holes/Kerr black holes/multiverse Penrose theory.

You can use this for whatever.

https://drive.google.com/file/d/1T7-OoMVPr3QkDWAFh5P0Ql9vcoRhzCgz/view?usp=sharing

Thanks guys,
Mehul

White Holes

Everyone knows of Black hole but most things in the universe have an opposite like matter and anti matter, therefore what is the opposite of something that sucks in everything including light. The answer is a white hole. White holes are very interesting for everyone as it is something that is difficult to imagine. What could be the function of the opposite of a black hole, this is what I'm here to tell you about.

A white hole is a hypothetical region of space time which cannot be entered from the outside although matter and light can escape from it. This must be difficult to imagine. If matter and light cannot enter then how can anything exit as for there to be an exit there must first be an entry. This question is what scientists are trying to answer and their success has been rather limited. Recently in fact some scientists suggested that the Big Bang might have been one massive white hole however due to the fact that the universe is expanding and our lack of knowledge of white holes, this theory has not gained momentum.

A white hole would attract objects just like anything else due to gravity but the objects would never actually reach the center and would keep losing momentum and would need more energy to accelerate. However eventually the amount of energy needed to accelerate past the resistance would be infinite and that number cannot be reached.

Finally my thoughts, I consider white holes to be interesting yet as there is no significant data I'll have to hold on before I put my thoughts down. If a significant discovery is found then I'll be sure to re-post about this topic.

This is Mehul

Signing Out

Space Elevator - the Future of Space Travel?

Some space fanatics might know this idea first proposed by Konstantin Tsiolkosky at 1895. He proposed the idea of a tower reaching geosynchronous orbit. However to make such an elevator we would need a material that is both lighter and stronger than anything we have right now. However the developments with nanotechnologies have allowed for new materials to be created such as Carbon Nanotubes which might just be strong and light enough.


To the right is a diagram showing the system recently proposed. The climber is the elevator with the idea of centrifugal force used to keep the space elevator stable.

The benefit of having a Space Elevator is quite simple. Spaceships launched at that height would already be in space and therefore would not have to escape earth's gravitational field. Due to this they would have more fuel and would not slow down as they would be in a vacuum.

The main reason why the building of this hasnt even started is again simply the price. Due to carbon nanotubes being a new technology, it is quite expensive and to build something on a magnitude of a space elevator would literally cost an unimaginable amount therefore for now there is not enough support but I honestly see this happening quite soon.

In fact, a Japanese company actually plans to have it built by 2050. Obayashi Corp has quite the inspiring goal to have it built soon and I wish them all the luck in succeeding.

Below is another picture detailing the concept behind it. May we all one day be able to take an elevator to space.

This is Mehul, Signing out.

Antimatter

My first post in a long time (Sorry Guys). Today, I will be talking about antimatter which is the "opposite" of matter per say.

Before we go into antimatter, lets look into what matter is made of. Matter is made of 'atoms and molecules' which contain protons, neutrons and electrons. These are made up of different kind of quarks such as up quark, down quark and strange quark to name a few. So technically, we can say that matter is made of particles such as quarks.

Anti-particles are basically particles which have the same magnitude for their properties but have the opposite sign for the specific elementary particle. For example, a positron has a charge of +1e with the same mass of an electron and is therefore considered as the antiparticle of the electron.

Matter and antimatter are said to annihilate (completely) into energy if they come in contact. For example, let's say a mass of 10kg antimatter is coming towards earth. When the antimatter comes in contact with earth(made of matter) 10kg of earth will be destroyed along with 10kg of antimatter and energy will be generated. This energy can be calculated by the formula e = mc^2. Of course this implies that in this scenario, 9 * 10^17J of energy (which is a very huge amount) will be produced along with the annihilation of both the matter and the antimatter. Radioactive rays are also released but that is a topic for another day.

Currently many scientists are trying to find a way to store matter however it cannot be stored in a container as the result would be annihilation. Therefore, some scientists are trying to use magnetic and electric fields as the antimatter containers instead however success is limited.

Thanks guys and more will be coming soon on a variety of astronomy topics.