Meteors, meteorites, meteoroids, etc.

Meteors, meteorites, and meteoroids are kind of interconnected.

Meteoroids is a small rocky or metallic object that is travelling through the space. Meteor is the streak of light that follows it (like the tail or the shooting star), it happens when the meteoroid burns in earth's atmosphere. And when it finally hits the earth, it is termed as meteorite.

Comets are heavenly bodies made of ice, dust and rock. these orbit the sun just like our earth. They are believed to be the remains from the formation of our solar system.

these are huge and when in their frozen state, they could be about the size of your city.

When they come closer to the sun, they heat up and release heat and gases, forming a tail called coma.

Asteroids are kind of the same thing, but they are more rocky in composition compared to comets, which are more icy. Asteroids are also remnants from the formation of the solar system. 

However, these guys lack a tail! 

Black Dwarfs

 Black dwarfs are one of the most interesting objects in the universe to me. 

They are essentially a theoretical remain of a white dwarf after it cools down and stops emitting heat or light. Now pay attention to the fifth word of the previous sentence.

Theoretical.

This means that we don't have a black dwarf in existence right now. Why is that, you may ask. I am going to discuss that later.

First let me elaborate the definition. When a star which has a size similar to that of our sun loses it's fuel, it becomes a white dwarf, emitting a lot of heat and light. When this white hole cools down, it no longer emits radiation heat and light, forming black dwarfs. 

Now coming back to what I mean by that they are not in existence right now. A star takes about 10 to 100 quadrillion years to become a black dwarf! Because as i mentioned earlier, first the star has to become white dwarf and then cool to become a black dwarf. 

And our universe is only about 13.8 billion years old. Meaning it would literally take ages for the formation of a black dwarf. 

Now, why are they so interesting to me?

A black dwarf's fate is to eventually explode into a supernova, and this would take about 10^1100 to 10^3200 years!

ARE WE STARDUST?

 “Some people are just light, glow, and hope… human stars.”

You might have heard that we are made of stardust. So, let us discuss that today.

First, we need to have some basic knowledge about the formation of elements. Basically, elements like hydrogen, lithium and helium were formed along with the big bang. All the other elements were formed through a complex process called stellar nucleosynthesis. We are not going to learn about that very deeply because it is a complicated topic to understand. 

And for a basic context, all stars have limited fuel inside their cores. When they run out of fuel, they die, which means that they convert into white dwarfs, black holes, or neutron stars, depending on their size (I talked about this in my neutron star post) 

When a massive star dies, it causes a huge explosion and cools down, hence forming a supernova. (A supernova is very bright, by the way.) So, when a supernova is formed, the elements inside the stars get spread all over the universe.

This material that they spread is what we call stardust. Stardust has a lot of other components in it (like ice, rock, etc.) other than just elements. But we will be right now just talking about the elements.

Now let us talk about the history of stars and their connection with human beings. So millions of years ago, the first generation of stars was formed. So the stars of this generation were very big than the ones we see now.

And we have another concept according to which the size of a star determines how fast it will burn its fuel. The size of the star is directly proportional to the rate with which the star burns its fuel. The bigger a star, the faster it will burn its fuel. Due to their weight, the first stars burned their fuels really fast and exploded into a supernova. These stars burned so quickly that they could only produce elements like hydrogen, helium and trace amounts of heavy metals inside them.

As the further generations appeared, more complex elements began forming.

Now, what does this have to with us? 

So our bodies (and everything else on our earth) are also made up of elements, and all the elements (except hydrogen and helium) out of these were formed in stars.

The calcium in your bones, the carbon in your skin, the iron in your blood, they all trace back to the stars that formed ages ago. So in some sense, we are stardust. 

Space Tourism: can we now wonder through the cosmos?

 Space tourism sounds amazing doesn't it. I mean who wouldn't want to travel to space one in their lives.

In this post, we will be discussing space tourism- it's history, milestones, major companies, and pros and cons.

Let's dive in.

Space tourism has two main types- Orbital and suborbital. suborbital flights take you to the Karman line which is 100 km above space. This flight is about a few minutes long.

An orbital flight takes you around the earth and takes about a few days!

Space tourism was first conducted in the year 2001. The first space tourist was a gentleman named Dennis Tito who paid about $20 million! This flight was conducted by the company Russian Soyuz. He was carried to ISS. And this was an orbital flight, of course. 

After Tito, Mark Shuttleworth did another orbital flight in 2002. And in 2006, Anousheh ansari became the first woman to take an orbital flight. 

Suborbital space travel came into the picture more recently. The first commercial suborbital flight was Galactic, launched by Virgin Galactic on June 29, 2023. The flight carried a crew of four. 

Another important milestone was SpaceShipOne which could carry about three people to space at once.

At present, the companies which plan to invest in and develop space tourism in the long term include Blue Origin, Space X and Virgin Galactic which mainly focus on suborbital travel.

Pros:

• Space tourism can provide non specialists to also have the experience to travel to space.
• If the sector flourishes, it could generate thousands upon thousands of jobs.
• We gain a new perspective on out earth when we view it from the outside.

Cons:

• The launching of these the space ships causes a lot of air pollution.
• Ordinary people cannot afford space travel.
• Prolong stay in the outer space can cause health damage due to reasons such as radiation exposure.
• Another issue is a bit ethical, imagine spending a fortune on sending the rich on a tour to space while the poor sit here, lacking food.

What are you opinions about space tourism? Do write about them in the comments. 

See you next Sunday!

Antimatter

In this post, we will be understanding something quite fascinating- antimatter. 

Basically, it is the mirror image of matter. As you must know that in the nucleus of the atom, lie neutrons, which have a neutral charge and protons which have a positive charge. In the orbits around the nucleus lie electrons, which have a negative charge. Electrons and protons are equal in number, neutralizing the effect of each other.

But in antimatter, it is the complete opposite. In the nucleus lie antiprotons which have a negative charge and in the orbits lie the positrons (anti electrons) which have a positive charge. 

When antimatter and matter come in contact with each other, they both annihilate each other, leaving nothing but energy. It is believed that during the Big Bang, equal amounts of matter. But then a question arises. If equal amounts of matter and antimatter were created, they must have annihilated each other, and had left energy behind. But then why do we have all of this matter around us, while antimatter isn't so common.

Why has matter (Baryons) dominated antimatter?

This is what we call the Baryon asymmetry. We do not yet have any solid explanation behind this, but we do have some theories that might be some help. 

The most widely accepted theory is that of baryogenesis. This is a hypothetical phenomenon, according to which a tiny amount of surplus matter was created. so when matter and antimatter did annihilate, this tiny around survived and that is what everything we see around us is constituted of.

I hope you found this helpful. 

If you have any suggestions feel free to drop them down. 

See you next Sunday!

Dwarf Galaxies: to small to be galaxies

Dwarf galaxies are simply galaxies relatively smaller in size and containing just a few hundred of thousand or just a few few billions of stars. This sounds like a lot, but when compared with larger galaxies such as ours (between 100 to 400 billion stars), the number appears somewhat smaller.

Being small and containing lesser stars, they have low mass. Due to the lack of abundance of stars, they have low luminosity too. They are very common actually. 

In fact loads of them also orbit other galaxies. take ours for example. The Milky Way has at the very least, about 14 galaxies orbiting it. 

Formation: Dwarf galaxies can be formed due to the collision between galaxies, which ejects streams of materials and dark matter, which cluster together to form smaller dwarf galaxies.

Another possibility can be that they were formed during the early stages the creation of the larger galaxies.

Types: Dwarf galaxies can be broadly categorized into five categories. Three of them are the same as the that of the 'regular' galaxies. But the last two get interesting.

Irregular dwarf galaxies:- They are irregular in their shape, just as the name sounds.

Elliptical dwarf galaxy:- They are ellipsoidal in shape, and smooth and featureless in appearance. 

Spiral dwarf galaxy:- Again, as the name suggests, they are spiral in shape (similar to the Milky Way)

Blue Compact Dwarf:- They contain massive hot stars (the blue ones are the hottest). These hot ones make the star look blue in colour.

Ultra Faint Galaxies:- They have the least number of stars, making them look faint. They also have large amounts of dark matter.

Examples: 

• Leo A: Irregular Dwarf galaxy
• Small Magellanic Cloud 2: Irregular Dwarf and a satellite of the milky way

Binary stars

When observed for a long time, some stars seem to change the amount of light emitting. It can be caused due to two reason. Either they are a variable star (which I will discuss in a separate post) or they are in a binary system and one star had eclipsed the other. 

In order to understand the massive paragraph above, you will have to understand the term 'binary stars."

BINARY STARS

Binary stars are a system of two stars which are gravitationally bound to each orbit a common centre (called the barycentre). 

These two stars can differ in shape, size, masses and stability. The larger star is called the primary star and the smaller star is called the secondary or the companion star.

The eclipses of these stars are very much important to us. These can help us in determining their size, shape, masses, diameters, and sometimes their orbits too.

Binary stars might seem uncommon but about 85% of the total stars exist in binary systems.

THE DEMON AND THE DOPPLER EFFECT

With some binary stars, we are lucky enough to discover their orbits simply by looking at them, but that is really not the case very often. For instance Algol (meaning demon in Arabic). 

In this binary stars system, the two stars are so close, that it is almost impossible to distinguish them as individuals, even through a telescope.

In such cases, the Doppler effect comes into help. The Doppler effect help in determining their individual orbits as they move farther from us and the colour of the light coming from them changes too.

ALLIANCE

If the two stars are very close, then one star's tidal effect can affect the other's shape and size, and hence influencing it's lifespan. These stars can sometimes collide to form elements like gold and platinum.

MULTIPLE STAR SYSTEM

just like two star system, multiple star systems also exist, though these are somewhat uncommon to find.

That is it for this post.

See you next Sunday!