What is Auroras?

What is Auroras?

If you’re ever near the North or South Pole, you may be in for a very special treat. Frequently there are beautiful light shows in the sky. These lights are called auroras. If you’re near the North Pole, it is called an aurora borealis or northern lights. If you’re near the South Pole, it is called an aurora australis or the southern lights. 

This beautiful view of the aurora was taken from the International Space Station as it crossed over the southern Indian Ocean on September 17, 2011.

What makes this happen?

Even though auroras are best seen at night, they are actually caused by the sun.

                           

The sun sends us more than heat and light; it sends lots of otherenergy and small particles our way. The protective magnetic fieldaround Earth shields us from most of the energy and particles, and we don’t even notice them.

But the sun doesn’t send the same amount of energy all the time. There is a constant streaming solar wind and there are also solar storms. During one kind of solar storm called a coronal mass ejection, the sun burps out a huge bubble of electrified gas that can travel through space at high speeds.

When a solar storm comes toward us, some of the energy and small particles can travel down the magnetic field lines at the north and south poles into Earth’s atmosphere.

                           

There, the particles interact with gases in our atmosphere resulting in beautiful displays of light in the sky. Oxygen gives off green and red light. Nitrogen glows blue and purple

The green bands of light in the sky are an aurora australis, an aurora at the south pole. Credit: Keith Vanderlinde, National Science Foundation

Do other planets get auroras?

These swirls of red light are an aurora on the south pole of Saturn. Image courtesy of NASA/ESA/STScI/A. Schaller.

They sure do! Auroras are not just something that happen on Earth. If a planet has an atmosphere and magnetic field, they probably have auroras. We’ve seen amazing auroras on Jupiter and Saturn.

                        

                     The NASA Hubble Space Telescope took this picture of a bright blue aurora on Jupiter.

credits: NASA

Why the Planets are Round?

Why the planets are round?

Scaled image of planets and sun relative to each other

Big, small, but all round

The eight planets in our solar system differ in lots of ways. They are different sizes. They are different distances from the sun. Some are small and rocky, and others are big and gassy. But they're all nice and round. Why is that? Why aren't they shaped like cubes, pyramids, or discs?

Planets form when material in space starts to bump and clump together. After a while it has enough stuff to have a good amount of gravity. That's the force that holds stuff together in space. When a forming planet is big enough, it starts to clear its path around the star it orbits. It uses its gravity to snag bits of space stuff.

A planet's gravity pulls equally from all sides. Gravity pulls from the center to the edges like the spokes of a bicycle wheel. This makes the overall shape of a planet a sphere, which is a three-dimensional circle.

Are they all perfect, though?

While all the planets in our solar system are nice and round, some are rounder than others. Mercury and Venus are the roundest of all. They are nearly perfect spheres, like marbles.

But some planets aren't quite so perfectly round.

Saturn and Jupiter are bit thicker in the middle. As they spin around, they bulge out along the equator. Why does that happen? When something spins, like a planet as it rotates, things on the outer edge have to move faster than things on the inside to keep up. This is true for anything that spins, like a wheel, a DVD, or a fan. Things along the edge have to travel the farthest and fastest.

Courtesy. NASA. 

What is Galaxy?

What is Galaxy?

We live on a planet called Earth that is part of our solar system. But where is our solar system? It’s a small part of the Milky Way Galaxy.

A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems. A galaxy is held together by gravity. Our galaxy, the Milky Way, also has a supermassive black hole in the middle.

 

When you look up at stars in the night sky, you’re seeing other stars in the Milky Way. If it’s really dark, far away from lights from cities and houses, you can even see the dusty bands of the Milky Way stretch across the sky.

Courtesy. Nasa and 500px

About Space Science

Space science

Study of everything in outer space. This has sometimes been called Astronomy, but recently astronomy has come to be regarded as a division of broader space science,which has grown to include other related fields, such as studying issues related to space travel and space exploration (including space medicine), space archaeology and science performed in outer space

Milky way Galaxy