CSB #4: Dark Worlds

Definitions:

Anomaly: Something that deviates from the norm

Dark Matter: Matter that is thought to exist based on gravitational effects on visible objects and radiation. It is hypothesized to account for discrepancies between measurements of galaxies and the universe.

Summary:

Just as Neptune was discovered by Johann Gottfried Galle after receiving a letter from Urbain le Verrier suggesting an unknown object whose gravitational pull was affecting Uranus' orbit, astronomers observe anomalous cosmic motions, which lead them to search for the new matter that is the cause. Once Neptune was discovered, we found that stars and galaxies do not move in ways they should. From the anomalies we see, we can come up with some theories. For one, we can deduce the existence of dark matter, which seems to be a sea of invisible particles that fill space unevenly, and dark energy, which is spread out though space uniformly and "acts as if it is woven into the fabric of space itself." Dark matter outweighs normal matter by 6 to 1. Scientists are increasingly considering the possibility that another universe is hidden by dark matter, in which there are identical hidden galaxies, planets, people, etc. Because of the large amount of dark matter compared to ordinary matter, astronomers assume that hidden galaxies are embedded in giant balls or "halos" of dark matter, and that for this dark matter to be unseen and undetectable, it must consist of particle that rarely interact with ordinary matter or even with one another. Force-carrying particles, known as W and Z particles that were discovered in the 1980s, display properties that hint at the existence of dark matter. For example, they have a very high mass, which suggests that some matter is acting on them. Other particles that closely resemble our thoughts of dark matter particles are WIMPs (weakly interacting massive particles), which have a high mass and only interact by means of a weak nuclear force, just as dark matter particles do. Scientists have come to think that dark matter is made up of WIMPs, which do not interact with the visible world. However, scientists also ponder: "might dark matter in fact have a rich inner life?" Dark matter could be interacting through many different forces, including a form of light to which our eyes are completely blind.

Discussion:

I think it's fascinating how our universe is filled unevenly with dark matter. It causes discrepancies between measurements of galaxies and the universe, while dark energy is a permanent part of the universe. It's truly intriguing how there could be other "hidden" galaxies and planets. There can even be the possibility of a hidden planet that is identical to ours, in which there are similar forms of life. Reading this article really made me want to find out what exactly dark matter is, and what role it plays in our universe.

Questions:

• Due to the discrepancies between measurements of galaxies and the universe, could it be possible that our universe is truly not as big or small as we think it to be?
• Could there really be other "hidden" planets with forms of life on them? How would they thrive?
• How did dark matter really come to be, and what is it made of?

Sources:

Feng, Jonathan, and Mark Trodden. "Dark Worlds." Science Reference Center. EBSCO
Host, Nov. 2010. Web. 8 Jan. 2011. .