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Reference Terms
from Wikipedia, the free encyclopedia

Dark matter

In astrophysics and cosmology, dark matter is hypothetical matter of unknown composition that does not emit or reflect enough electromagnetic radiation to be observed directly, but whose presence can be inferred from gravitational effects on visible matter.

Note:   The above text is excerpted from the Wikipedia article "Dark matter", which has been released under the GNU Free Documentation License.
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Space & Time News

November 22, 2024

A massive collision of galaxies sparked by one travelling at a scarcely-believable 2 million mph (3.2 million km/h) has been seen in unprecedented detail by one of Earth's most powerful telescopes. The dramatic impact was observed in Stephan's ...
While astronomers have taken about two dozen zoomed-in images of stars in our galaxy, unveiling their properties, countless other stars dwell within other galaxies, so far away that observing even one of them in detail has been extremely ...
An asteroid struck Mars 11 million years ago and sent pieces of the red planet hurtling through space. One of these chunks of Mars eventually crashed into the Earth and is one of the few meteorites that can be traced directly to Mars. This meteorite ...
Astronomers have identified three ultra-massive galaxies -- nearly as massive as the Milky Way -- already in place within the first billion years after the Big Bang. This surprising discovery was made possible by the James Webb Space Telescope's ...

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