The Shapely supercluster

In one of the previous posts, we discussed the Great Attactor. In that post, I also mentioned the Shapely Supercluster. This post is going to discuss the supercluster in detail. 

The Shapley Supercluster, also known as the Shapley concentration or SCI, is one of the largest known mass concentrations in our universe. Its mass is at least 10¹⁵ solar masses. This mass includes galaxy clusters and groups like Abell 3558 and Abell 3562. It is located in the north of the constellation of Centaurus.

It is more concentrated than the Great Attractor, and it has an even greater force of gravitation. Its force is so much that even the Great Attractor is being pulled towards it!

I know it sounds so insane.

For better understanding, let us compare it to the Laniakea Supercluster from the Great Attractor post. The size of the Laniakea galaxy supercluster is about 530 million light years. The Shapely Supercluster expands roughly over an area of 600 million light years!

That is it for today. I hope you liked it. If I made mistakes or if you want me to write about anything else, feel free to comment. See you next Sunday!

The colour of the sun: definitely not what you think!

 Have you ever wondered what colour our sun actually is? Is it red, orange or yellow?

What if I told you it is none of these! What if I told you the colour of the sun is actually white. Yes white.

You may ask, why do we see it as red or orange?

Yes, you see it as red or orange because of the scattering of light. You might know that when a beam of white light is passed through a prism, it scatters into multiple colours.

That is exactly how light from the white light from the sun scatters when it passes through our atmosphere. This is called Rayleigh Scattering. 

The amount of light scattered depends on the wavelength of a particular ray. A large amount of blue and indigo waves (shorter waves) get scattered away from the path to our eyes. Red and orange waves (longer ones) don't get scattered in large amounts and reach our eyes. Therefore, they came right to us making it appear red or orange.

However, in the evenings, sunlight has to pass through a thicker layer of the atmosphere. Due to this, this scattering increases and larger amounts of blue light get scattered away. This is why the sky looks red or orange during the sunsets. 

Note: Pictures like the one included in this post are just for demonstration purposes.

I hope you understood this. If you have any suggestions for me please drop them down in the comments. See you next Sunday!!

The great attractor

The great attractor, as we call it is a fascinatingly mysterious region. It has immense mass (equal to that of a 1000 trillion suns!) This mass is so much that it increases the gravitational force of the region, driving it to pull galaxies (including ours) towards it.

Let us dive deep into the mystery.

The great attractor is located in the gravitational centre of the Laniakea Supercluster of galaxies (which includes the Milky Way). Now it is not a single star or a blackhole. Instead, it is a massive concentration of mass. The great attractor is about 150 to 250 million light years away from us.

However, we cannot study it much as it is located in the Zone of avoidance meaning it is difficult to observe it using any telescope. However, scientists are trying to use X-ray and infrared observations to study the Great Attractor. 

But with what we know right we and some other galaxies are being pulled towards it at the speed of 600 kilometres per second!

But, we're not done yet. There is another supercluster called the Shapley Supercluster whose gravitational pull is stronger than that of the Great Attractor. This is why the Milky Way and the Great Attractor, are both getting attracted towards it. 

And now, before you get worried know that we will actually never collide with the great attractor. This is because of the rapid expansion of our universe. The fabric of the universe is expanding faster than the speed of light! So, we would kind of move further away from it reather than getting close.

But the great attractor is still an unsolved mystery.

Three exoplanets where life would exist

The universe is unimaginably vast and continues to be. So here we are uncertain if we are alone. In this post, I want to talk about three exoplanets that might give us hope that we are not alone.

(Before diving into them, know that all of these planets are in the habitable zones of their stars, meaning liquid water could potentially exist there. However, I want to clarify that we cannot say for certain that liquid water definitely exists.)

Kepler-186f 

Discovered by Elisa Quintana on 17 April 2014, Kepler 186f is an exoplanet 580 light years away from us. A year there is just 130 Earth days. As mentioned above it is in the habitable zone of its star. But to know for certain, we need information about its atmosphere. The planet is too far for us to be able to acquire any knowledge about its atmosphere.

Also, planets, Kepler-186b, c, d and e are all tidally locked, (meaning one side of the planet always faces the planet.) The chances of Kepler-186f being tidally locked are about 50%. 

Based on all the knowledge that we have, the planet does not have a tilt like that of our Earth. This means that there will be no seasons like those here on Earth. However, it could have a significant tilt if there is a planet revolving between Kepler-186f and Kepler-186e we haven't yet discovered.

Kepler 22b

Kepler 22b, an exoplanet 600 light years away from us, is another planet that is in the habitable zone of its star. It is about 2.4 times the size of our Earth!

The planet takes about 290 Earth days to complete its orbit. 

If it had an atmosphere similar to the Earth's, its temperature would likely be 22°C. 

So, it stands as a pretty strong candidate, but we are uncertain about the composition of this planet (more than the others actually). We don't know if it is rocky planet or a gas giant. 

HD40307 g

Exoplanet HD40397 g is a part of the HD40307 star system. It is about 42 light years away from home. Now this is significantly closer to the other planets we discussed above. But 42 light years is still really far away (3.974 × 10¹⁴ km). 

Anyways, it is a super Earth as its mass is 7.1 times more than that of our Earth. The planet takes 197.8 Earth days to complete its orbit. 

And it is most likely not tidally locked, which is a plus. 

But that is it for this post. If I missed anything or if you want me to write about a topic, please comment down below. See you next Sunday. 

light pollution

Have you ever looked up and wondered where all the stars have gone and why the sky looks so dull. 

I like to spend most of my nights gazing up at the stars. But every time I found the sky empty, a strange and incomprehensible sadness filled my heart. 

While researching this post I stumbled upon a term called 'Noctalgia'. This term is used to describe the feeling of sadness or longing for the dark skies. 

Now, we don't get to see dark skies anymore due to light pollution. Light pollution is caused by excessive and inefficient use of artificial light.

According to Wikipedia, about 83 per cent of the human population lives under light-polluted skies. 

To make matters worse, light pollution has increased by 49 per cent from 1992 to 2017. 49 per cent!

Light pollution might seem like a small stargazing-related problem but it is way worse than that. 

First, let's talk about the impacts of light pollution on human health. Light pollution causes headaches, constant fatigue, stress and anxiety. Some studies have even shown that light pollution causes severe diseases like breast and prostate cancer. 

Light pollution does not just harm human health but also animals and plants. 

Many animals rely on moonlight to navigate paths for migration. Artificial light at night (ALAN) can confuse them.

ALAN leads to hormonal imbalances and affects sleep cycles in animals.

In plants, ALAN disrupts their photoperiod (the amount of sunlight a plant receives during a 24-hour period). This further disturbs photosynthesis.

As I have mentioned before, ALAN also affects star gazing as we cannot see the galaxies and the stars anymore.  ALAN also makes it harder to see further astronomical events which can be really helpful for new discoveries.

We just talked about the impacts of light pollution, but what about the steps we can take to reduce and limit it.

As individuals, can obviously reduce the use of artificial light unnecessarily and switch off the light when not in use.

But we would need to use them after all. So we can use efficient LED lights that direct light downwards. We can use warm tones of lights instead of the blue ones. When we switch the lights in our rooms, we can put on our curtains to prevent a lot of light from going out of the room.

Some communities measure, we can take our educate, the public about, like pollution And its negative impacts.

We can encourage dark sky parks where there is less lighting and people can come and enjoy the dark skies. This one would be hard but really helpful in the long run. 

One measure that authorities can take is to set timers on the street lights. And for the dark sky parks, I talked about earlier, the government can provide funds for that too. 

I hope you like this post if you have any questions or want me to write about any other topic, comment down below. I will meet you guys next Sunday.

Thanks for reading!!

The Beginning of our Universe: The Big Bang

Have you ever wondered what led to the beginning of our beautiful universe? Well, we cannot say for certain, but with all the scientific evidence we have it is most likely The Big Bang. 

The Big Bang Theory is a physical Theory that suggests how the universe might have been formed. 

The theory suggests that before the universe was formed there was a dense and super hot point. This point which had no atoms and no structure is said to be a singularity. Now this singularity went through extreme hot which resulted in its rapid expansion and subsequent cooling. This expansion continues until today and will most probably continue for a long time. 

This whole event was named The Big Bang. 

The first person to propose that the universe might be expanding was Georges Lemaître in 1927. 

His proposal was confirmed by Edwin Hubble two years later.

We also have evidence to back the Big Bang theory. It is a phenomenon called cosmological Redshift which occurs due to the Doppler effect of light.

When an object moves far from us (I am talking light years), it takes light a lot of time to reach us. Due to this, the wavelength of light stretches and the light reaches the end of the spectrum and appears red.

As I told you before, the universe is continuously expanding, the space between expanding, leading to our galaxies moving away from each other. This leads to cosmological redshift, and Redshift is used to determine the distance between two heavenly bodies.

Some people have suggested some alternatives to thw Big Bang theory. The most popular ones include The Steady State Theory, Eternal Inflation, etc. However, these have been rejected by most cosmologists.

If you have any questions, or if I made any mistakes, or you want to me write about a topic, feel free to comment!