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.

                                               Source

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

                                         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:

                                               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:

                                   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!

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The Sun in it’s Cosmic Brilliance

fuckyeahphysica:

Our Whole world revolves around ( quite literally ) around this teenage star known as the Sun. These Images have been false-colored to help us perceive “the star” that lies beyond our visual cognizance.

Have a good one!

Also check out : https://www.nasa.gov/mission_pages/sunearth/news/light-wavelengths.html

Source: nasa.gov

OKay.. THis might seem like a stupid question.. But why doesn’t the earth spiral into the sun ? Like why is orbiting it ?

In a recent post we demonstrated using the Newton’s cannon thought experiment that:

ISS and other satellites are always falling, but they are falling in Orbit

And this applies to planetary bodies too: Earth is always trying to fall into the sun, but it keeps falling in an orbit instead

But where did the initial velocity for the earth come from ?

Well, to answer that question one needs to go back 4.6 Billion years ago and look at the formation of the solar system.

And if you like numerical simulation and are wondering how could a spinning cloud of gas eventually form planets, take a look at the following video and its source paper.

Thanks for asking!

Try bringing two of your fingers closer in the back drop of a light source and you would observe this:

Long before your fingers actually touch, the edges magically seem to touch each other. How is this even possible?

Transit of Venus

When scientists were observing the transit of Venus from Earth i.e when the planet Venus passes directly between the Sun and Earth,they faced a similar problem. 

At the moment when Venus should
nearly touch the edge of the sun, the circular planet began to elongate.

                                                PC: NASA

And they noticed the same phenomenon for Mercury as well (which has no atmosphere).

What is causing this optical phenomenon?

The physics behind this beautifully bizarre optical phenomenon will be revealed tomorrow on FYP!.

But since this is something that you can all try at home, we strongly encourage you to play around with this and get a feel for it. It requires only your hands and a source of light.

Once you do, try to hypothesize  a solution for this behavior.

Have fun!

EDIT: NOT TO SCALE!

Well.. Now you know!

Image Source,  Gif Source

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
process:

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

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).

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.

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

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 😀

The Sun in it’s Cosmic Brilliance

Our Whole world revolves around ( quite literally ) around this teenage star known as the Sun. These Images have been false-colored to help us perceive “the star” that lies beyond our visual cognizance.

Have a good one!

Source: nasa.gov

The fabric of Space and Time.

I have got an increasing number of requests to write about Black Holes in the past couple of weeks. So, to kick-start we will start talking about Space-time Fabric.

Redefining Gravity.

When we usually talk of Gravitation we are bound to think like Newton, where objects are assumed to exerting a force upon each other. Like imaginary arrows of force in space. But this picture, although good for high school crumbled, with the advent of Einstein’s theory of Relativity. ( We will explore the question of why in an upcoming post.)

What is the Space-Time Fabric?

Think of spacetime fabric as an actual cloth of fabric. When you place an object on the fabric, the cloth curves. This is exactly what happens in the solar system as well. 

The sun with such a huge mass bends the space-time fabric. And the earth and all the planets are kept in orbit by following this curvature that has been made by the sun.

The earth – moon system can be thought of in the same manner. 

A natural question to ask at this juncture would be:

Why don’t planets just swirl into the sun?

To put it bluntly, they stay in their orbits because there is no other force in the Solar System which can stop them.

The Solar System was formed from a rotating cloud of gas and dust which spun around a newly forming star, our Sun, at its center. The sun did pull objects towards itself. But the planets that we see today were resilient and stuck with their course. And time passed, the net force acting on them turned to zero and will continue to be zero.

Gravity and Light.

Light is affected by the Gravity. This was discussed in a previous post about Gravitational Lensing. 

The gravitational field of a really massive object is super strong. And this causes light rays passing close to that object to be bent and refocused somewhere else.

This is a consequence of the fact that space- time curvature is bent by objects which have a huge mass. When light is passing through this dent the rays of light are directed in another direction. And this causes effects like gravitational lensing.

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**This post was inspired by this video – Gravity Visualized. Hope you enjoyed reading this post. If you have any doubts or queries, feel free to ask. Have a Good Day 🙂

PC: zmescience,

Comets have two tails.

There are two types of comet tails: dust and gas ion.

A dust tail contains small, solid particles that are about the same size found in cigarette smoke. This tail forms because sunlight pushes on these small particles, gently shoving them away from the comet’s nucleus. Because the pressure from sunlight is relatively weak, the dust particles end up forming a diffuse, curved tail.

A gas ion tail forms when ultraviolet sunlight rips one or more electrons from gas atoms in the coma, making them into ions (a process called ionization). The solar wind then carries these ions straight outward away from the Sun. The resulting tail is straighter and narrower. Both types of tails may extend millions of kilometers into space. As a comet heads away from the Sun, its tail dissipates, its coma disappears, and the matter contained in its nucleus freezes into a rock-like material.

Comets don’t like the sun.

Comets lose a lot of mass when they go by the Sun. A lot: some shed hundreds of tons of material per second.
That’s actually a small fraction of the mass of a comet, but given
time, and lots of solar passes, it adds up. Every comet we see is slowly
dissolving in space. Eventually even the mighty Comet Halley will be
gone, broken down into a swarm of rocks, gravel, and dust once its gas
is gone.

Source: hubblesite.org