After discovering new stars and other matter with the advent of better optics and other technology?

Question

Do the new discoveries lower the estimated amount of Dark Matter in the Universe

Answer 1

Not yet. The data on the amount of dark matter out there is hard to get, of course, because dark matter is so difficult to "observe" - was never "observed" at all prior to 2006, in fact.

They are only just beginning to establish exactly where the dark matter even is, by its apparent gravitational effect:

http://planetary.org/news/2007/0109_Hubble_Creates_First_3D_Map_of_Dark.html

Specifically how much of it there is? We're a ways from knowing that definitively. We don't even yet know what non-baryonic matter is.

http://en.wikipedia.org/wiki/Dark_matter

Answer 2

E is correct: no.

In fact, if anything, the more we discover, the bigger the Universe seems to be and the further we are from having discovered sufficient mass to explain the behaviour of the universe.

(although there are also some new approaches that may do away with some or all of the need for dark matter)

Once the Big Bang was accepted as a possible theory, an early question was whether there was sufficient mass in the universe for gravity to make it fall back on itself (Big Crunch).

Because we can't measure the entire mass of the universe (it may be infinite in some dimensions) the approach was to determine the density of matter in the part visible to us.

This density was called Omega and units were chosen so that the break-even point was 1.

If the overall density of the universe (Omega) is greater than 1, then the universe is "closed" and will fall back onto itself. If Omega is less than 1, then the universe is "open" and will continue to expand forever.

When the first calculations were done, Omega appeared so close to 1 that scientists agreed that it should be exactly 1; it was only the lack of our own instruments and methods that prevented us from identifying all matter (we were seeking only very little dark matter). With Omega = 1, we would have a "flat" universe.

Nowadays, it appears that Omega is really a lot less than 1. Yet, many things in the universe (e.g., galaxies within clusters) are behaving as if the real matter density was a lot more (up to nine times, according to some) than what is provided by matter we can observe and identify. The rest is what we call dark matter.

Today, we are looking for a lot more Dark Matter than what we were looking for fifty years ago. That is because our understanding of the universe (mainly its true size and the movement of clusters and super-clusters of galaxies) has improved.

However, whenever some matter is identified and measured, it is no longer part of "Dark Matter", it is lumped with known matter (a.k.a. Baryonic matter, even if not made of baryons) and its value is removed from the quantity of Dark Matter we are searching for.

One (old) example is when an unknown mass was perturbing the orbit of planet Uranus. When Neptune was found, it was no longer unknown mass.

Problem is that the size of what we are looking for keeps growing faster than what we are finding...

Answer 3

No