Universe - Otteri selvakumar (best books to read for beginners txt) 📗

areas, scientists can witness the gravitational force of the black holes.

Black holes vary in size from smaller than an atom (with the mass of a large mountain) to one million times the mass of the sun.

 

 

 

 

 

 

There are two classifications of black holes: stellar and supermassive.

Supermassive black holes are found at the center of every large galaxy. They are, as the name suggests, enormous. Our own galaxy’s black hole (Sagitarrius A) has a mass equal to about four million suns. These black holes are created when giant stars collapse in on themselves.

Stellar black holes can be tiny—the size of an atom— but their mass is far greater. Typically, stellar black holes have a mass that’s 20 times greater than the sun. While the Milky Way has only one supermassive black hole, it has many stellar black holes.

 

 

 

 

 

That Mysterious Dark Matter and Dark Energy

We’ve established that the universe is expanding. But as scientists observed this expansion, it didn’t seem to be operating according to standard physics. The funny thing is, scientists observed, rather than slowing down (which is what normally happens when you have gravity working on mass), the universe’s expansion is actually accelerating.

Using the Hubble Telescope to view a distant supernova, scientists observed in 1998 that the universe was once accelerating at a slower rate than it is today. This made no sense to scientists. And, truthfully, there’s a lot they still don’t know.

Scientists came up with the theory of dark energy to explain the accelerated expansion. Basically, it surmises that there is another mysterious energy at work on the universe: so-called dark energy. So, then, what is dark matter? It’s the stuff that scientists know must be out there, but is not observable.

And although we don’t know a whole lot about dark energy and matter (though there are several different working theories), we do know that they compose a large part of the universe. Scientists believe that 68% of the universe is dark energy, 27% is dark matter and only 5% is what we currently can observe. Yep, you read right: only 5%.

 

In 2003, NASA launched two robot explorers—rovers Spirit and Opportunity—which successfully landed on Mars in January 2004. Each equipped with a panoramic camera, thermal emissions spectrometer and a host of other sophisticated instruments, the rovers search for and analyze rocks and soil that may

hold information about past water on the planet. Although Spirit has been silent since 2012, Opportunity continues to send scientists valuable data almost a decade later.

 

Coolest Party Ever: The International Space Station

The International Space Station (ISS) is a joint effort between the United States, Russia, Japan, Canada and Europe. This habitable artificial satellite, complete with a laboratory, is the most politically complex space endeavor ever embarked upon. It is also the

largest man-made object orbiting the planet. It orbits 330 kilometers above Earth and travels 7.71 kilometers per second.

The first module of the station was sent up in 1998, and it was first inhabited in November 2000 by the crew members of Expedition 1. Since then, 40 more expeditions have been sent to live in the station. The purpose of the station is to conduct research, encourage cooperation and promote education. It has been continuously occupied for 14 years, the longest human presence ever in space.

 

 

Going Commercial with Space Exploration

Space exploration is costly and challenging. To help defer costs and encourage innovation, NASA has begun working with the private sector to develop space exploration systems. Space X and Virgin Galactic are at the forefront of non-governmental research and development.

Space X was founded in 2002. In 2010, it became the only private company to return a spacecraft from low- Earth orbit. In 2012 it brought cargo to the International Space Station, a feat it has repeated numerous times.

Virgin Galactic is developing a craft that it hopes will be used for space tourism in the future. Although it has been testing crafts (SpaceShip One and SpaceShip Two), it is still working toward this go

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Publication Date: 11-10-2017

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Dedication:
I am writing you to hear sum of sense science fiction essays for speaking with the universe so long history of our universe I am little bit like to write here to my collection with this essays about the world. I am try that's all dedication for Universal love