jueves, 10 de octubre de 2013

What do we know about the Universe?

The Universe is everything we can see, touch, feel, sense, measure or detect. It includes living things, planets, stars, galaxies, dust clouds, light, and even time. Before the birth of the Universe, time, space and matter did not exist.
There are billions of galaxies in the Universe, galaxies are made of millions of stars. Perhaps, most of these stars have planets around them, just like our Solar System. The space between galaxies is almost empty: only few atoms of hydrogen per cubic centimeter. Space also has radiation, like the light and heat, magnetic fields and high energy particles,
The Universe is incredibly huge. It would take a modern airplane more than a million years to reach the nearest star to the Sun. Travelling at the speed of light (300,000 km per second), it would take 100,000 years to cross our Milky Way galaxy alone.
No one knows the exact size of the Universe, because we cannotsee the edge – if there is one. The Universe has not always been the same size. Scientists believe it began in a Big Bang, which took place nearly 14 billion years ago. Since then, the Universe has been expanding outward at very high speed. So the area of space we now see is billions of times bigger than it was when the Universe was very young. The galaxies are also moving further apart as the space between them expands.
(Adapted from ESA Kids.)

As you have read the Universe is so big that we need new units of measurement; Two of them are the light year and the astronomical unit. What is a light year? What is an astronomical unit?

7 comentarios:

  1. Isabel Fernández García13 de octubre de 2013, 3:44

    This blog is very interesting.
    I loved everything about the universe and the Big Bang theory , to be the event from which the universe began to expand rapidly , and gives much to think about .
    Galaxies , formed by a number of stars illuminating , are really impressive , especially our great Milky Way , which in fact our solar system is only a small accumulation of insignificant planets .
    When we think about all that today , thanks to our advanced technology and tireless and brilliant scientific minds of what we know about the universe compared to a few thousand years ago , when even we believed that the Earth was the center of the universe , or even before, seems a worthy accomplishment to be proud of , and although it is so, we make the mistake of thinking that we know everything about the universe , but I think , that as much as forward, never will reveal every last incognita our mysterious and fascinating universe.

  2. Thank you very much for your comment. I hope you enjoy with our blog.

  3. Almudena Martin Martinez.13 de octubre de 2013, 12:48

    A light year is 300000 km.
    One equals UA 150000000km.

    1. Are you sure that a light year is only 300.000 km?

  4. Almudena Martin Martinez.13 de octubre de 2013, 22:32

    I like the universe and its stars galaxies and more things that form the universose formed by the big bang theory which is a big explosion.
    A light year is the light sollar light travels in one year equals 300.0000km per second.
    One AU equals 150.000.000km which is approximately the average distance between Earth and the Sun

  5. Sandra Rodríguez García 1º ESO B16 de octubre de 2013, 9:05

    Light Year : A light year is a unit of distance , equal to approximately 9.46 × 1012 km = 9,460,730,472 580.8 km.1 2

    It is calculated as the length that light travels in one year. More specifically, a light year is the distance that a photon in vacuum during a Julian year ( 365.25 days of 86 400 s ) at the speed of light ( 299,792,458 m / s ) at an infinite distance from any gravitational field or field magnético.1

    A light year is a unit of length (a measure of the length of all Einsteinian spacetime ) . Scientists in specialized fields is preferred parsecs (about 3.26 light-years ) and its multiples for astronomical distances , whereas light year is still common in popular science divulgación.1 length units are also based on other periods , as the second minute light and light used especially to describe distances within the Solar System , but also often restrict outreach work as specialized contexts is preferred astronomical unit (approximately 8.32 minutes light).

    Astronomical Unit : The astronomical unit (abbreviated ua , au , UA or AU ) is a unit of length equal by definition to 149 597 870 700 meters , 1 which is roughly the average distance between the Earth and the Sun This definition is in place since the general assembly of the International Astronomical Union August 31, 2012 , in which annulled the Gaussian definition used since 1976 , it was " the radius of a circular orbit undisturbed Newtonian and around the Sun described a infinitesimal mass particle moving average of 0.01720209895 radians per day '.2

    The symbol ua is recommended by the International Bureau of Weights and Measures and the International Standard ISO 80000 , while au is the only considered valid by the International Astronomical Union , 1, and the most common in English-speaking countries . It is also common to see the symbol in capital letters , UA or AU , although the International System of units using only capital letters for symbols of units are named after a person.

    The name comes from the sixteenth and seventeenth centuries, when not yet accurately calculated absolute distances between solar system bodies , and only known relative distances using the standard average distance between Earth and the Sun , which was called astronomical unit . It was said that the day that this value is measured , " they would know the size of the universe ."

  6. Adrián García Sánchez15 de octubre de 2014, 6:51

    hello , my name is adrian and my constelacion is scorpion