Across astronomical distances, the only significant fundamental force of physics is gravity. However astronomers usually find that their calculations don't quite match up. An undetected form of matter (dark matter) was theorized to fix this.
Recently I have read an article about that the universe consist of 70% dark energy, 25% dark matter, and only 5% of visible matter or energy. Now, some of you may be confused by words 'dark matter' and 'dark energy'. Let me explain it.
'Dark matter' is a matter which doesn't reflect or emit electromagnetic radiation. The existence of dark matter is inferred from gravitational effects on visible matter (like stars or galaxies). 'Dark energy' on the other hand, is an energy which permeates space and exerts a negative pressure. This could have gravitational effects on visible matter. Dark energy cannot be observed directly. It can be rather inferred from observations of gravitational interactions between astronomical objects. This was all very well explained by Michael Turner so you can google it.
The interesting fact is that only 5% of universe is a visible matter/energy. We cannot be sure what is in 95%. However we do know for sure that calculations don't match when we assume that 100% of universe consist of visible matter/energy. That's why scientist came up with theory of dark matter/energy. Yet we still don't know what stands behind the phrase 'dark matter'.
Recently I have read an article about that the universe consist of 70% dark energy, 25% dark matter, and only 5% of visible matter or energy. Now, some of you may be confused by words 'dark matter' and 'dark energy'. Let me explain it.
'Dark matter' is a matter which doesn't reflect or emit electromagnetic radiation. The existence of dark matter is inferred from gravitational effects on visible matter (like stars or galaxies). 'Dark energy' on the other hand, is an energy which permeates space and exerts a negative pressure. This could have gravitational effects on visible matter. Dark energy cannot be observed directly. It can be rather inferred from observations of gravitational interactions between astronomical objects. This was all very well explained by Michael Turner so you can google it.
The interesting fact is that only 5% of universe is a visible matter/energy. We cannot be sure what is in 95%. However we do know for sure that calculations don't match when we assume that 100% of universe consist of visible matter/energy. That's why scientist came up with theory of dark matter/energy. Yet we still don't know what stands behind the phrase 'dark matter'.
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