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.

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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.

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                                               Source

Since there are different types of gases that compose the sun, there are numerous wavelengths of light that get absorbed by these gases.

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                                         Source: xkcd

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:

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                                               Source

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:

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                                   Source: Earth Blog

We can even take it one step further by finding the composition of other neighboring stars as well.

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                                  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!

Hey look ! A supernova.

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 :

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                                                   Source

And which translates to:

O’
 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”

image

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
night sky.

But on a cloudless night in the suburbs, one can be a witness to the
spectacles of the universe. Here’s what i mean:

image

                                           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 😉

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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.

** View the milky way with your naked eye

fuckyeahphysica:

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
of mass.

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”.

image

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
binary system

 

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.

This
also determines an empirical mass-luminosity relationship (MLR) from
which the masses of single stars can be estimated.

image

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
triplets.

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.

image

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.

image

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.

image

An example of this is
Cygnus X-1.

A binary Black Hole system ?

Definitely!
A binary black hole (BBH) is a system consisting of two black holes in close orbit around each other.

image

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

Black Holes are not so Black (Part 3) – Gravitational Waves

fuckyeahphysica:

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.

image

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.

image

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
process:

First, a vast swarm of ice and rock ‘planetesimals’ formed.
These comet-sized bodies collided and accumulated into ever-larger
planetary embryos.

image

Once an embryo became about as massive as ten Earths,
its self-gravity became strong enough to pull in gas directly from the
disk. 

During this second step, the proto-Jupiter gained most of its
present mass (a total of 318 times the mass of the Earth).

image

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.

image

A binary star system is those systems having
two stars.they both revolve around themselves in their own orbits.

It is
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
unusual.

In other star systems the mass distribution of the stars is equitable, but in ours the sun decided to not let that happen

image


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 😀

TL;DR

The sun grabbed most of the mass during the formation
of the solar system and threw a huge solar wind which knocked off all of
Jupiter’s surrounding gases, making it a failed star.

Electroluminescent wires.

Electroluminescent wire (often abbreviated as EL wire) is a thin copper wire coated in a phosphor which glows when an alternating current is applied to it.

A Star Wars Geek?

In the spirit of the new Star Wars movie, you can even make your own lightsaber with these EL wires. 🙂

image

Have a Great day!

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PC: LogiNevermore  ajserb

Celestial Wonders- Binary Stars.

image

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 of mass.When two stars appear close together in the sky, 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 binary system.

image

Artist’s impression of the sight from a (hypothetical) moon of planet HD 188753 Ab (upper left), which orbits a triple star system( yes, a Triple Star system!). The brightest companion is just below the horizon.

image

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. This also determines an empirical mass-luminosity relationship (MLR) from which the masses of single stars can be estimated.

It is estimated that approximately 1/3 of the star systems in the Milky Way are binary or multiple, with the remaining 2/3 consisting of single stars.

The Brightest star in the sky is a binary.

image

This is true. When it was discovered in 1844 by the German astronomer Bessel, the system was classed as an astrometric 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 ?

image

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 Cygnus X-1.

The universe is pretty amazing huh?…

Why did the Earth start spinning?

Our Solar System formed about 4.6 billion years ago when a huge cloud of gas and dust started to collapse under its own gravity.

As the cloud collapsed, it started to spin. Some of the material within this cloud gathered into swirling eddies and eventually formed into planets. As the planets formed, they kept this spinning motion. This is similar to what you see when skaters pull in their arms and spin faster. As material gathered in more closely to form a planet, like Earth, the material spun faster.

Why does the Earth still Spin?

To put it bluntly, the earth is still spinning because there are no forces acting to make it stop spinning! This is known as Inertia – an inherent law of nature.

Inertia is the tendency of an object to remain in motion unless and until acted upon by an unbalanced force.

( Source : http://coolcosmos.ipac.caltech.edu/ask/59-Why-does-Earth-spin-)