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Our Universe

Our intelligence species has done magnificent work in regards to knowledge gained, especially over the last century. Humans have always wondered about the universe, stars, where we have come from and what our universe is made of. Throughout history people have employed a variety of techniques and methods to understand how far the sky goes above their head, how big it is, and how it began (and perhaps Why). The Big Bang Theory is an explanation, agreed on by most scientists, of how the universe came into existence several billion years ago. The theory says that about 13.7 billion years ago the universe violently expanded from an extremely compact, dense, and hot state of energy and elementary particles. The universe has been expanding and cooling since then.

The first elements generated at the beginning were the simplest and lightest: hydrogen and helium. These two lightest chemical elements were and still are the most plentiful elements in the universe. All stars derive most of their energy during their lifetimes through the nuclear fusion of these light elements into heavier elements.

In 1922, Russian physicist Alexander Friedman derived from Albert Einstein's general theory of relativity a set of equations which showed that the universe is expanding and which has served as the framework for the current theoretical work on the concepts of the big bang theory. American astronomer Edwin Hubble provided some clear supporting evidence of the theory with his discovery in 1929 of the universal shifting of the light produced by distant galaxies toward the red end of the spectrum. “Tired light” theories, which say that light loses energy, slowly and naturally becoming red as the time passes, were soon dismissed, leaving receding galaxies as the most plausible explanation. Hubble found that galaxies which were farther away were moving away at a proportionally faster rate, which showed that the universe is expanding uniformly. Calculating this expansion back in time brings us to the singular dense state from which it all began.

According to the latest theoies to explain observations of the movements of distant galaxies, the universe is composed of 23% dark matter, about 72% dark energy, and about 5% ordinary matter (everything we can actually currently detect).

In our own galaxy, drifting in interstellar space, are huge, diffuse clouds of gas and dust known as nebulas. A stellar nursery is a nebula in which star formation is occurring, such as the Eagle nebula; whereas a planetary nebula is a shell of gas and dust ejected from a star in a giant explosion. However, planetary nebulae have nothing to do with planets.

Dark Matter Dark Energy & the Unknown Universe

Dark Energy ****** Cosmic Super Zoom

Solar System

By simply looking up into our night sky we are only able to see the stars in our own galactic neighbourhood. However with increasingly sophisticated techniques and methods employed by astronomers, we have found that our universe is made up of billions of galaxies, with each galaxy containing billions of stars, and many stars hosting multiple planets. Our home planet resides in our own unique solar system which itself resides in the galaxy we know as the Milky Way.  

Solar system formation began billions of years ago, when gases and dust began to come together to form the Sun, planets, and other bodies of the solar system. Our solar system is filled with a wide assortment of celestial bodies - the Sun itself, our eight planets, various dwarf planets, and a large number of asteroids and comets - and on Earth, the unique circumstances of our Solar System and our planet gave rise to life itself! The inner solar system is occasionally visited by comets that loop in from the outer reaches of the solar system on highly elliptical orbits. In these outer reaches we find the Kuiper Belt and the Oort cloud. And somewhere in this distant realm is the limit of the heliosphere, where the billowing solar wind of energized particles from the Sun loses steam and is overwhelmed by the interstellar medium.

Most galaxies in the universe, including our own Milky Way, harbor at their centres supermassive black holes varying in mass from about 1 million to about 10 billion times the size of our Sun. To find them, astronomers look for the enormous amount of radiation emitted by gas which falls into such objects during the times when black holes are active, i.e., accreting matter. This gas "infall" into massive black holes is believed to be the means by which black holes grow."

Earth-sized planets... Astronomers are presently looking for Earth-like planets and have so far found very few. Our technology limits our ability to detect much more than large planets. The question of “Are we Alone” still is out there, but I personally believe we are not alone. I am just hoping that if there are others out there, that they are doing better than us. I am hoping they haven’t ruined their habitat, and that they don’t have war, displaced peoples or hunger. With all those billions of galaxies and billions of stars, the chances are very good that there are other habitable planets with people. I don't anticipate that that will be the fantastic creatures we see in sci-fi films. If the whole universe is made of the same material, then the life everywhere may have amazing similarities.

 

More Useful Links:

2013 Solar Storm Could Create Widespread Panic

Posted on: Tuesday, 15 June 2010, 09:20 CDT
"NASA has warned that the Earth could endure a once-in-a-generation "space storm," bringing widespread power blackouts and leaving people without critical communications signals for a long time...."

No direct link between black holes and dark matter Scientists show that black hole growth is mostly connected to the formation of the galaxy bulge and not to dark matter

The Largest Black Holes in the Universe

New Discovery about the Fabric of Space-Time

New findings provide important observational indicators for testing different theoretical models of how the orbits of planetary systems have evolved. "Disk-planet interaction models of migration focus on interactions between the planet and its protoplanetary disk. Sometimes interactions between the protoplanetary disk and the forming planet result in forces that make the planet fall toward the central star. These models predict that the spin axis of the star and the orbital axis of the planet will be in alignment with each other."

Scientists are now using a simple but powerful technique to see the Cassiopeia A supernova in 3-D. "Our telescopes show the Milky Way Galaxy only as it appears from one vantage point — our solar system. Now, using a simple but powerful technique, a group of astronomers led by Armin Rest of Harvard University in Cambridge, Massachusetts, has seen an exploding star, or supernova, from several angles."

The Expanding Universe

Hawking's universe

barbar

LHC at CERN

Brian Cox on CERN's supercollider

CERN-The European Organization for Nuclear Research

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