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In astronomy, dark matter is a hypothetical form of matter that does not interact with light or other electromagnetic radiation.Dark matter is implied by gravitational effects which cannot be explained by general relativity unless more matter is present than can be observed.
Since this C-inversion does not affect gravitational mass, the CPT theorem predicts that the gravitational mass of antimatter is the same as that of ordinary matter. [5] A repulsive gravity is then excluded, since that would imply a difference in sign between the observable gravitational mass of matter and antimatter. [citation needed]
Dark matter is called ‘dark’ because it’s invisible to us and does not measurably interact with anything other than gravity. It could be interspersed between the atoms that make up the Earth ...
Weakly interacting massive particles (WIMPs) are hypothetical particles that are one of the proposed candidates for dark matter.. There exists no formal definition of a WIMP, but broadly, it is an elementary particle which interacts via gravity and any other force (or forces) which is as weak as or weaker than the weak nuclear force, but also non-vanishing in strength.
The universe's contents include ordinary matter - stars, planets, gas, dust and all the familiar stuff on Earth, including people and popcorn - as well as dark matter, which is invisible material ...
About 90% of all matter appears to be dark matter, which has mass (or, equivalently, gravitational influence), but does not interact electromagnetically and, hence, cannot be observed directly. [140] There is no generally accepted description of this new kind of matter, within the framework of known particle physics [141] or otherwise. [142]
Collisionless: Dark matter particles interact with each other and other particles only through gravity and possibly the weak force; Dark matter constitutes about 26.5 % [12] of the mass–energy density of the universe.
As "dark matter", baryonic dark matter is undetectable by its emitted radiation, but its presence can be inferred from gravitational effects on visible matter. This form of dark matter is composed of "baryons", heavy subatomic particles such as protons and neutrons and combinations of these, including non-emitting ordinary atoms.