Space

Astronomy is the study of space. If you were an astronomer, you might focus on galaxies, stars, planets, or traveling objects such as comets and asteroids. Don't get astronomy confused with astrology. Astrology is a form of mystical prediction based on the stars and the time of year. Horoscopes are based on astrology. Astronomy is grounded in science. Astronomy uses math and science to study and predict the actions of the universe.

SPACE EXPLORATION

Humans rarely visit other planets. Humans do take pictures of other universal bodies. From those pictures we study the colors, movement, and composition of other objects in the universe. Astronomers need to understand the sciences of Earth because this is the only place we can study firsthand. Astronomers work with chemistry when studying the atmospheres on other planets. Astronomers need to understand geology to explain the structure of planets and stars. Astronomers also need to know physics to explain how objects move through the universe.

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The countries of the world are currently building a space station that orbits the Earth. This is the first step in our efforts to colonize and study the Solar System. One day (maybe in your lifetime), there may be groups of scientists working on the Moon and Mars. As time passes, Earth will also send more probes into deep space to study the outer planets and the interstellar region outside of our system. Even though the study of space has been 
going on for thousands of years, we have only been able to study the universe firsthand for about 40 years.



What is the Size of the Universe?

How does one measure the size of the Universe? The challenge in measuring the size of the Universe doesn’t lie on its enormity. Simply put, if you want to measure a really big area, all you need is a really long measuring stick.

Here is more Info Estimated Size of Universe:-

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970630c.html