"DO YOU KNOW TECHNICALLY PLANETS DON'T ORBIT AROUND THE STARS?" - AVIK DUBEY

INTRODUCTION :- From a young age we all don’t study a very basic thing that way and many are not interested in knowing more real things about the beautiful universe because of the crushing education system. This type of system spoiled our curious mind to think more about the laws of nature. In this blog, I don’t want to talk about our education system but it is about the very primary Physics. I’ll give you two questions, right now, which you might need to know for your correct understanding about science. Here they are:

 Q1.) What does the moon revolve or orbit around?

 Q2.) What does the Earth orbit around?

If you’re like most people, the answers to these questions will be the Earth and Sun, respectively. We tend to think of a smaller celestial body orbiting a larger one. The moon orbits the Earth and the Earth orbits around the Sun.

For simplicity’s sake, that’s kind of what we say, and that’s it.

The detailed truth of the matter is different, however. The Earth doesn’t technically orbit around the Sun, and the moon doesn’t orbit around the Earth either. Planets and stars actually orbit around their common center of mass. This common canter of mass is called the ‘Barycenter’. Barycentres also help astronomers search for planets beyond our solar system!

What is a Center of Mass ?

Every object has a center of mass. It is the exact center of all the material an object is made of. An object’s center of mass is the point at which it can be balanced.

Sometimes the center of mass is directly in the center of an object. For example, you can easily find the center of mass of a ruler. Try holding your finger under the middle of a ruler in a few different spots. You’ll find a spot where you can balance the whole ruler on just one fingertip. That’s the ruler’s center of mass. The Center of mass is also called the center of gravity.

 

                                                                                                                              

 But sometimes the center of mass is not in the center of the object. Some parts of an object may have more mass than other parts. For example, A sledge hammer has most of its mass on one end, so its center of mass is much closer its heavy end.

                                                                                                                            

In space, two or more objects orbiting each other also have a center of mass. It is the point around which the objects orbit. This point is the barycenter is usually closest to the object with the most mass.

 

                                                                                                                                                

Barycenter in our solar system :- Where is the barycenter between Earth and the Sun? Well, the Sun has lots of mass. In comparison, Earth’s mass is very small. That means the Sun is like the head of the sledge hammer. So, the barycenter between Earth and the Sun is very close to the center of the Sun.

Jupiter is a lot larger than Earth. It has 318 times more mass. As a result, the barycenter of Jupiter and the Sun is not in the center of the Sun. It’s actually just outside the Sun’s surface! Our entire solar system also has a barycenter. The Sun, Earth, and all of the planets in the solar system orbit around this barycenter. It is the center of mass of every object in the solar system combined.

                                                                                                                                       

Our solar system’s barycenter constantly changes position. Its position depends on where the planets are in their orbits. The solar system’s barycenter can range from being near the center of the Sun to being outside the surface of the Sun. As the Sun orbits this moving barycenter, it wobbles around.

How do barycentre help us find other planets: - If a star has planets, the star orbits around a barycenter that is not at its very center. This causes the star to look like its wobbling.

 

                                                                        As seen from above, a large planet and a star orbit their shared center of mass, or barycenter.

 

                                                                      As seen from the side, a large planet and a star orbit their shared center of mass, or barycenter. The slightly off-center barycenter is what makes the star appear to wobble back and forth.

 Planets around other stars called exoplanets are very hard to see directly. They are hidden by the bright glare of the stars they orbit. Detecting a star’s wobble is one way to find out if there are planets orbiting it. By studying barycentres and using several other techniques astronomers have detected many planets around other stars.