Skip to main content

What is a Black Hole ?

A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.
Because no light can get out, people can't see black holes. They are invisible. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently than other stars.
A black hole can not be seen because strong gravity pulls all of the light into the middle of the black hole. But scientists can see how the strong gravity affects the stars and gas around the black hole. Scientists can study stars to find out if they are flying around, or orbiting, a black hole.
When a black hole and a star are close together, high-energy light is made. This kind of light can not be seen with human eyes. Scientists use satellites and telescopes in space to see the high-energy light.
Scientists think the smallest black holes formed when the universe began.
Stellar black holes are made when the center of a very big star falls in upon itself, or collapses. When this happens, it causes a supernova. A supernova is an exploding star that blasts part of the star into space.
Scientists think supermassive black holes were made at the same time as the galaxy they are in.


YouTube Link - https://www.youtube.com/watch?v=e-P5IFTqB98

Credits - https://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-a-black-hole-k4.html


Comments

Post a Comment

Popular posts from this blog

What is Reflection of Light ?

Reflection is a very common word and is related to the fields of physics and mathematics. The basic meaning of a reflection is  ‘Something Returned in Response’ . Even in our conversation we use this term at times, to mean a some one’s reaction. In optics, it relates to an image of an object. Light rays are basically wave motions and they are capable of being reflected by an interface in between two mediums. Such interfaces are called  Light Reflectors .  The most common Light reflector is the one we use many times a day, which is nothing but a plane mirror. But it is not only a plane mirror reflects light. Even a curved mirror does that though the nature of reflection of light by curved mirrors is different. YouTube Link -  https://www.youtube.com/watch?v=9PRRUgoTSro Credits -  http://physics.tutorvista.com/light/reflection.html
2 comments
Read more

What is HUNTERS MOON ?

The term “ Hunters Moon ” is used traditionally to refer to a full moon that appears during the month of October. It is preceded by the appearance of a “Harvest Moon”, which is the full moon closest to the autumnal equinox (which falls on the 22nd or 23rd of September). It is also known as a sanguine or “ Blood Moon ". The Hunter’s Moon typically appears in October, except once every four years when it doesn’t appear until November.  The name dates back to the First Nations of North America. It is so-called because it was during the month of October, when the deers had fatted themselves over the course of the summer, that hunters tracked and killed prey by autumn moonlight, stockpiling food for the coming winter. YouTube Link  -   http://www.mirror.co.uk/news/uk-news/hunters-moon-2016-what-can-9050088 Credits -  https://c2.staticflickr.com/4/3819/10355721434_6992b719fa_b.jpg
Post a Comment
Read more

What is Universe ?

The universe is all the matter, energy, and space that exist. We can observe only a part of it - the observable universe. The entire, universe, including the part we cannot see, may be infinite. Galaxies form and evolve within an expanding and cooling universe. Because light takes billions of years to cross the cosmos, we see distant galaxies as they were at earlier times. Astronomers not only theorize about cosmic evolution - they can actually observe its various stages. The Big Bang is the scientific description of the origin of the cosmos. It describes the beginning of the universe as an explosion of space, which has expanded and cooled ever since. If we rewind the expansion of space and go backward in time, galaxies crowd closer and closer together in the past. Ultimately, all matter and energy is compressed at extremely high density and temperature. The observable universe fits within a volume smaller than a grain of sand. That superdense medium exploded in the Big Bang, l...
Post a Comment
Read more