Which is evidence for the existence of dark energy?
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1 point
galaxies that are rotating at a constant rate
Pulsars that seem to be moving closer at an accelerating rate
Black holes that are expanding at a constant rate
Supernovae that are moving away at an accelerating rate
Supernovae that are moving away at an accelerating rate is evidence for the existence of dark energy.
The evidence for the existence of dark energy is supernovae that are moving away at an accelerating rate.
The evidence for the existence of dark energy comes from the observation of supernovae that are moving away at an accelerating rate. To understand how this evidence supports the existence of dark energy, we need to delve into some cosmology concepts.
First, it is important to note that dark energy is a theoretical concept introduced to explain the observation that the expansion of the universe is accelerating. The current leading theory is that dark energy is a repulsive force that counteracts the gravitational attraction between matter and causes the observed acceleration.
Supernovae are exploding stars that release immense amounts of energy. By studying the brightness and redshift (the shift towards longer wavelengths) of distant supernovae, scientists are able to determine their distance from us and how fast they are moving away.
The key evidence for dark energy comes from the observation that distant supernovae are moving away from us at an accelerating rate. This means that the expansion of the universe is getting faster over time, rather than slowing down due to the gravitational attraction between galaxies.
To obtain this evidence, scientists use a technique called Type Ia supernovae standard candles. Type Ia supernovae are known to have a consistent peak brightness, making them useful for measuring distances in the universe. By comparing the expected brightness of a Type Ia supernova with its observed brightness, scientists can determine its distance. When the distances to these supernovae were measured, it was found that they were farther away than expected if the expansion of the universe was only influenced by the gravitational pull of matter. This discrepancy implies the existence of an additional force, known as dark energy, which causes the accelerated expansion.
In summary, the evidence for the existence of dark energy comes from the observation that supernovae are moving away from us at an accelerating rate. This discovery challenged the prevailing view of a slowing down expansion and instead led to the hypothesis of dark energy, which provides the explanation for this accelerated expansion.