Post by glactus on May 7, 2009 2:53:32 GMT
An artist's rendering of the Milky Way galaxy
Beware the Milky Way. The galaxy we call home is far larger,mightier and brighter than most other galaxies in the Universe. Shining with the light of hundreds of billions of stars, and shrouded in a lethal web of dark matter, the Milky Way galaxy can capture and annihilate luckless galaxies that stray into its domain.
Evidence of this was first noticed quite recently, when by sheer accident a small galaxy was discovered in Sagittarius. Older type stars were seen travelling at different speeds to the main stream, the remains of a dwarf galaxy that has ventured too close to the Milky Way, and as you read, is being pulled apart by its gravity.
The Milky way has so disrupted this small galaxy that its stars are now stretched over a 20,000 light years long region of space the shape of a cigar.
There are 9 small galaxies within one million light years of the Milky Way, and two that are not classified as dwarfs as they are much larger. These are the Magellanic Clouds, and because they are so massive, may cuccumb to what is known as "dynamic friction."
Surrounding the Milky way is a huge halo of matter. The extent of the halo is unknown, but the Magellanic Clouds as well as the Sagittarius dwarf probably lay within it and will suffer the same fate.
As the galaxies plough through the dark matter they are slowed down by its gravity, robbing them of their orbital energy and pulling them closer to the Milky Way. As dynamic friction pulls thenm in, tidal effects will increase and eventually rip the galaxies apart. When this happens to the Magellanic Clouds in a few billion years, it will trigger the birth of a huge number of stars and our galaxy will be bigger and brighter than ever before.
These events testify to our galaxy's enormous power for the Milky Way has probably swallowed up many dozens of smaller galaxies in its lifetime - our star as well
Brutal as it may seem, our galaxy's cannibalism may have contributed to the creation of the living beings who inhabit a planet which orbits a star called the Sun, for we are out on a spiral arm, three quarters the distance from the heart of the galaxy - deep within the zone that may belong to stars from other galaxies.
The questions remain -
Have we always been there? Has our star always belonged to this galaxy? Where did we really come from? Is this the reason that we have spiritual feeling and why the whispers of the cosmos are calling us? Is this the force that drives us on - back to the void from whence we came?
We are too entwined in the Milky Way now, and we will never know.
Credits: Image.
This is a NASA/JPL-Caltech image