Dark matter/energy

[simay77]

Please excuse my ignorance if the following is nonsense.

 

I watched a program last night on the BBC (Horizon) that explained in lay mans terms the theories behind dark energy and dark matter. If I understood correctly neither have been seen by the most advanced telescopes on the planet. This means that they cannot be measured/quantified.

 

Surely then it must be possible that both exist in our own atmosphere(?) and that their relationship with gravity varies depending on the surrounding elements.

 

Also could a black hole not be explained as negative dark energy?

[snark1100]

The existance of dark matter is inferred from observing the rotation of distant

galaxies, and finding that the observed mass - stars, dust, etc., of the galaxy

isn't large enough to explain the observed rotation.

Dark energy on the other hand is inferred from observations suggesting that the universe is expanding at an accelerating rate, suggesting something - dark energy - is driving it appart.

[CraigD]

If I understood correctly neither [dark energy or dark matter] have been seen by the most advanced telescopes on the planet.

Correct. “Dark” in this context means “unobservable” – that is, emitting or reflecting, or absorbing no or too little light (photons of any frequency) to be observed.

This means that they cannot be measured/quantified.

Not exactly. As Snark1100 notes, just because we’re unable to observe “dark” stuff directly, we can still detect it by its effect on the ordinary matter in stars and galaxies

Surely then it must be possible that both exist in our own atmosphere(?) and that their relationship with gravity varies depending on the surrounding elements.

It’s not unreasonable that our atmosphere could have dark stuff in it. Detecting it could be difficult, though.

 

One of the known particles many people think may make up some or all of the dark matter is the neutrino. They have very little mass (possibly none, in which case it’s no good for explaining dark matter), and interacts so slightly with ordinary matter that detecting one is nearly impossible. Although theory predicts that the Sun is (harmlessly) bombarding the earth with a lot of them – millions per second in a single square centimeter – the best massive underground detectors have detected only a few tens of them.

 

So, dark matter could be all around us, even in us, and we might not be able to detect it.

Also could a black hole not be explained as negative dark energy?

I don’t think so.

 

Black holes, and their smaller cousins, neutron and quark stars, are thought to be made or ordinary matter – compacted into weird, poorly understood forms, but still ordinary, non-dark matter - the remnants of burned-out, collapsed stars. Most black holes have a lot of hot matter circling them in “accretion disks”, so are far from dark, they’re some of the brightest (in the x-ray spectrum) objects in the sky.

 

:eek2: If you enjoy fictional explorations of Science, I recommend Steven Baxter’s novel ”Ring” for a wild look at dark matter, and its possible long term impact on the universe.

[Harry Costas]

Hello someone wanted info on Dark Matter.

If it matters I have some links.

If its a matter of facts.

 

http://www.cfht.hawaii.edu/News/Lensing/#IC

http://antwrp.gsfc.nasa.gov/apod/ap960202.html

http://www.astro.queensu.ca/~dursi/dm-tutorial/dm1.html

http://www.space.com/scienceastronomy/astronomy/cosmic_darknrg_020115-1.html

 

other APOD images discussing dark matter

here is a few

http://antwrp.gsfc.nasa.gov/apod/ap030804.html

http://antwrp.gsfc.nasa.gov/apod/ap030814.html

http://antwrp.gsfc.nasa.gov/apod/ap031126.html

 

http://antwrp.gsfc.nasa.gov/apod/ap030611.html

http://antwrp.gsfc.nasa.gov/apod/ap030109.html

 

But there is lots more

 

Dark Matter is yet to be explained.