The proper motion of 61-Cygni at one year intervals.
Emojis of the cosmos
Pareidolia is a psychological phenomenon in which the mind responds to a stimulus, usually an image or a sound, by perceiving a familiar pattern where none exists.
These are merely some images of stars and galaxies taken by the Hubble Space Telescope. But what do you see ?
This is the visible spectrum of the light from the sun. And if you have played with white light and prisms before, it might come as a huge surprise to you to know that the spectrum from the sun is actually not continuous.
Why is it not ? The dark patches in the above spectrum arise from gas at or above the
Sun’s surface absorbing sunlight emitted below.
Since there are different types of gases that compose the sun, there are numerous wavelengths of light that get absorbed by these gases.
How do we know which line corresponds to which ? Well, it’s because we have a periodic table, and we know the spectrum of all the elements in it:
And then it’s a matter of solving the jigsaw puzzle of fitting the spectrum with the tiles that you have. When we do so, we obtain the following composition of elements:
Source: Earth Blog
We can even take it one step further by finding the composition of other neighboring stars as well.
Source: Potsdam University
All of this information about the star can be captured from a simple spectrum. And this is why one of the most important tool that an astronomer has about an object is it’s spectrum.
Have a good one!
Robert Evans with his reflecting telescope
Robert Evans is the world record holder for the most visual discoveries of Supernovae. Although he is a minister of the uniting church in Australia, he is better known in the Astronomy community as one of the ‘best Amateur Astronomers in the world.’
He is accredited for discovering 42 supernovas visually from his backyard!!
But, how on earth does he do it ?
Having been looking at the cosmos for years on end, Evans has memorized the entire star field and the positions of the galaxies in the night sky.
And as a result of this, he can detect changes in the galaxy simply by looking at them through the telescope.
Why is this remarkable ?
This is truly remarkable for two pivotal reasons:
A supernova is the explosion of a star. It is the largest explosion that takes place in space.
But spotting a supernova visually is extremely hard!
To give a perspective on the intricacies of supernova hunting, here is a picture showing the night sky before and after a supernova in Messier-82.
Supernova hunting in Messier-82
And secondly, he gave automated telescopes a run for their money. There are many telescope in recent times that automatically detect hundreds of supernovas every year.
But Evans managed to give them a tough fight in a battle against man and technology with his telescope sorcery.
A note for budding astronomers
Why I find Evans to be extremely inspiring is because here is an amateur astronomer doing quality contributions to Astronomy in his backyard and with not so fancy equipment.
Just shows how far passion and perseverance can take you in science.
Be limitless! Have a great day!
Yesterday’s post: Spectacular time-lapse from birth to death of a Supernova
Physicists have a dark sense of humor
Have a great week !
One of my friends was telling me about this sloka in sanskrit and the meaning of it, being a physics geek it blew my mind .
There is this sloka in sanskrit that praises Lord Ganesh and it goes like this :
And which translates to:
Lord with a twisted trunk and a mighty body, One whose brilliance is
equivalent to the brightness of 10 million suns, my Lord, always make
all my endeavors free of obstacles.
“One whose brilliance is equivalent to the brightness of 10 million suns”
Where would you find a brightness equivalent to 10 million suns – A supernova of course! Is it possible that the sloka is referring to a supernova ?
Are supernovas that bright in the sky ?
Absolutely. If you reside in a city, there is something known
as light pollution that prevents us from staring at the magnificence of the
But on a cloudless night in the suburbs, one can be a witness to the
spectacles of the universe. Here’s what i mean:
PC :Jeremy Stanley
So, yeah it is a possibility that when the scripture was drafted a bright supernova might have been a predominant sight in a crystal clear night sky.
So, What does this mean ?
Well, the earliest known supernova observations goes as back as 185 CE, when the supernova SN185 appeared. And curious astronomers around the world have been documenting these celestial wonders for ages.
But of course, they did not call it ‘Supernova’. That name had just had not been invented yet 😉
The guest star reported by Chinese astronomers in 1054 is identified as SN 1054. The highlighted passages refer to the supernova.
So, that’s the bite sized knowledge cookie I wanted to treat you guys on this Thursday.
If you are interested, this wikipedia page comes with a plethora of valuable references that would quench your thirst.
Have a great day!
** Important : Read about Light pollution and what it does.
Celestial Wonders- Binary Stars (#1)
The twins of the stellar world are binary star systems.
A binary star is a
star system consisting of two stars orbiting around their common center
When two stars appear close together in the sky as seen from the Earth when viewed through
an optical telescope, the situation
is known as an “optical double”.
This means that although the
stars are aligned along the same line of sight, they may be at
completely different distances from us. This occurs in constellations;
however, two stars in the same constellation can also be part of a
Why study Binary stars ?
Binary star systems are very important in astrophysics because
calculations of their orbits allow the masses of their component stars
to be directly determined, which in turn allows other stellar
parameters, such as radius and density, to be indirectly estimated.
also determines an empirical mass-luminosity relationship (MLR) from
which the masses of single stars can be estimated.
Also,it is estimated that 75% of the stars in the Milky Way galaxy are
not single stars, like the Sun, but multiple star systems, binaries or
The Brightest star in the sky is a binary.
This is true. Sirius (aka the Dog star) – the brightest star in the sky is actually a binary star system.
When it was discovered in 1844 by the German astronomer
Bessel, the system was classed as an astro-metric binary, because the
companion star, Sirius B, was too faint to be seen.
Bessel, who was also
a mathematician, determined by calculations that Sirius B existed after
observing that the proper of Sirius A (the main star) followed a wavy
path in the sky, rather than a uniform path.
Sirius can now be studied
as a visual binary because, with improving technology and therefore
improved telescopes, Sirius B was able to be seen, although not for 20
years after Bessel had correctly predicted its existence.
Black Holes in a binary system ?
Hell Yeah! The term “binary system” is not used exclusively for star systems,
but also for planets, asteroids, and galaxies which rotate around a
common center of gravity.
However, this is not a trick question; even in
star binaries, the companion can be a black hole.
An example of this is
A binary Black Hole system ?
A binary black hole (BBH) is a system consisting of two black holes in close orbit around each other.
In fact the LIGO experiment which confirmed the existence of Gravitational waves was able to acquire its data when two Binary Black Holes Collided and merged into one. This phenomenon sent ripples in the fabric of space-time which we call as a Gravitational Wave.
The Universe is amazing huh?
If you found this interesting, check out:
A Denied stardom status – Jupiter
Of all the planets in our solar system, Jupiter seems to stand out as this massive giants.
When scientists started uncovering the secrets of this mysterious planet, they discovered that Jupiter was probably a ‘star in the making’ during the early years of the solar system.
Jupiter and the sun
Jupiter has a lot in common with the sun than you think.
It is made of the same elements such as Hydrogen and Helium that are found in the sun and other stars!
But it is not massive enough and does not have have the pressure and temperature to fuse the existing Hydrogen atoms to form helium, which is the power source of stars.
How do stars form ?
Stars form directly from the collapse of dense clouds of
interstellar gas and dust. Because of rotation, these clouds form
flattened disks that surround the central, growing stars.
After the star
has nearly reached its final mass, by accreting gas from the disk, the
leftover matter in the disk is free to form planets.
How was Jupiter formed ?
Jupiter is generally believed to have formed in a two-step
First, a vast swarm of ice and rock ‘planetesimals’ formed.
These comet-sized bodies collided and accumulated into ever-larger
Once an embryo became about as massive as ten Earths,
its self-gravity became strong enough to pull in gas directly from the
During this second step, the proto-Jupiter gained most of its
present mass (a total of 318 times the mass of the Earth).
But sadly soon
thereafter, the disk gas was removed by the intense early solar wind (from our sun) ,
before Jupiter could grow to a similar size.
This destroyed all hopes that Jupiter had on becoming a star
What if it had become a star ?
If Jupiter had become a star,our solar system would have
become a binary star system.
A binary star system is those systems having
two stars.they both revolve around themselves in their own orbits.
interesting to note that most of the solar systems in the universe are
binary,triple or higher multiple star systems but our sun is rather
In other star systems the mass distribution of the stars is equitable, but in ours the sun decided to not let that happen
Why? We have no clue ! Scientists are still trying to fathom these mysterious details of the birth process. But the more we know, the more we learn we don’t know 😀
Black Holes are not so black! – Part 1
A black hole is a concentration of mass great
enough that the force of gravity prevents anything from escaping it
except through quantum tunneling behavior.
How can you get out of one?
To get out of the earth’s clutches, we need to travel at least at 11.2 km/s also called the escape velocity.
Similarly, since the gravitational strength of a black hole is so strong, the escape velocity ( if you intend to leave it ) exceeds the speed of light.
Where does it gets it’s gravitational powers?
To understand this, let’s do a thought experiment: What would happen if we compress earth to half its present radius without changing the mass density?
The gravity at the surface would be four times more because of the “inverse square law”. It gets stronger at shorter distances.
And now, say you keep on decreasing the radius even further, the gravity would just keep on spiking to phenomenal levels. This is the secret to the Black Holes extraordinary gravitational powers.
How are they even formed?
All stars follow a life cycle. I will elaborate on the life cycle in another post, since its kind of long. But this illustration from sciteachers would do for now:
Upon reaching a certain critical density, a star will collapse on its own weight. i.e Its radius will keep on decreasing and gravity swooping up at each stage untill it collapses to an almost infinitely small pinpoint.
And that’s how black holes are formed and why they have such a huge gravitational pull on Objects.
Hope you learnt something new about blackholes in this post. This is a series and we will dig deeper as we move down the line. As they say- tiny drops make a mighty ocean. Small baby steps at a time everyday and at the end we will attain colossal clarity! Have a good one.