Skip to main content

How much do we know about dark matter?

We don't know a lot about dark matter, mainly because all of our theories about it have not been supported by observational evidence that can be conclusively identified as dark matter.


The idea of dark matter originated with observations of galactic rotation, and recognizing that the gravitational effects being observed were much greater than the gravity that could be accounted for from normal matter. The "dark" aspect of dark matter is that it doesn't interact...

We don't know a lot about dark matter, mainly because all of our theories about it have not been supported by observational evidence that can be conclusively identified as dark matter.


The idea of dark matter originated with observations of galactic rotation, and recognizing that the gravitational effects being observed were much greater than the gravity that could be accounted for from normal matter. The "dark" aspect of dark matter is that it doesn't interact with the electromagnetic spectrum in any way; it only interacts with gravity. This might seem like the theory is being made up to fit the facts, but this is the only way to get observable predictions from something you can't see or touch.


The current theory, and the main pursuit of dark matter research, is that dark matter is composed of a particle, or particles, called WIMPs, which stands for weakly interacting massive particles. These particles are hypothetically "relics" from the early universe, basically closer in composition and properties to the "primordial" nature of the universe before it cooled and particles that we're more familiar with began to form. Several observational methods have been proposed, such as looking for interactions between WIMPs and normal matter, generating new WIMPs in a particle accelerator, or looking for signs of WIMPs being annihilated during particle collisions in space. To date, none of the experiments have provided conclusive evidence that WIMPs exist and have properties exactly correlated to this or that - in fact some of them are contradictory, such as the relatively new LUX experiment, which had no results under high-sensitivity observations whereas less-sensitive experiments produced hundreds of results. 


There's at least two other possibilities; the observations and calculations of gravitational effects are in error, or that another property of the universe is responsible for the gravitational difference being observed. Both have been considered, but the prevailing theory is that dark matter or something to that effect is responsible for the observations. 

Comments

Post a Comment

Popular posts from this blog

What is the meaning of "juggling fiends" in Macbeth?

Macbeth is beginning to realize that the three witches have been deceiving him since he first encountered them. Like jugglers, they have kept changing their forecasts in order create confusion. This is particularly apparent when the Second Apparition they raise in Act IV,   Scene 1 tells him that no man of woman born can overcome him in hand-to-hand battle--and then Macbeth finds himself confronted by the one man he has been avoiding out of a... Macbeth is beginning to realize that the three witches have been deceiving him since he first encountered them. Like jugglers, they have kept changing their forecasts in order create confusion. This is particularly apparent when the Second Apparition they raise in Act IV,   Scene 1 tells him that no man of woman born can overcome him in hand-to-hand battle--and then Macbeth finds himself confronted by the one man he has been avoiding out of a sense of guilt, and that man tells him: Despair thy charm. And let the angel whom thou still hast serve...
Post a Comment
Read more

Why did Tybalt attack and kill Mercutio instead of Romeo, who he had originally been targeting?

Though Tybalt's quarrel is with Romeo, he begins the momentous duel in Act 3 by fighting with and killing Mercutio instead. Tybalt ultimately attacks Mercutio because the garrulous and hot-headed character insults Tybalt and goads him into a duel to protect Romeo's honor. From the beginning of the encounter in Act 3, Scene 1, it's clear that Mercutio is itching for a fight. For instance, when Tybalt signals that he wants to talk to Mercutio... Though Tybalt's quarrel is with Romeo, he begins the momentous duel in Act 3 by fighting with and killing Mercutio instead. Tybalt ultimately attacks Mercutio because the garrulous and hot-headed character insults Tybalt and goads him into a duel to protect Romeo's honor. From the beginning of the encounter in Act 3, Scene 1, it's clear that Mercutio is itching for a fight. For instance, when Tybalt signals that he wants to talk to Mercutio and Benvolio, Mercutio responds "And but one word with one of us?/ Couple it w...
Post a Comment
Read more

Follow the relationship between Pi and Richard Parker. They endure over two hundred days of hardship together, but in the end Richard Parker leaves...

When Pi and Richard Parker are at the beginning of their journey, after Pi's family is killed in the shipwreck, Pi fears Richard Parker, but he is forced to find a way to co-exist with him in order to survive.  Over time the two develop a somewhat co-dependent relationship.  Richard Parker depends on Pi to feed him by catching fish, while Pi's will to live is bolstered by Richard Parker's presence.  Richard Parker recognizes that... When Pi and Richard Parker are at the beginning of their journey, after Pi's family is killed in the shipwreck, Pi fears Richard Parker, but he is forced to find a way to co-exist with him in order to survive.  Over time the two develop a somewhat co-dependent relationship.  Richard Parker depends on Pi to feed him by catching fish, while Pi's will to live is bolstered by Richard Parker's presence.  Richard Parker recognizes that he also needs Pi to survive.  At one point in the book, Pi's starvation and thirst reduce him to a st...
Post a Comment
Read more