Which is evidence for the existence of dark energy?
O galaxies that are rotating at a constant rate
O Pulsars that seem to be moving closer at an accelerating rate
O Black holes that are expanding at a constant rate
O Supernovae that are moving away at an accelerating rate
O 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 comes from observing supernovae that are moving away at an accelerating rate. This observation suggests that there is a force or energy causing this accelerated expansion, which has been referred to as dark energy.
The evidence for the existence of dark energy comes from observing the expansion of the universe. One of the key pieces of evidence is the observation of supernovae moving away at an accelerating rate.
To understand how this observation supports the existence of dark energy, we first need to know about the expansion of the universe. Scientists have determined that the universe is not static; instead, it is continuously expanding. This was first discovered by Edwin Hubble in the 1920s, based on the observation that distant galaxies appear to be moving away from us.
However, it was expected that gravity would slow down the expansion of the universe over time. Yet in the late 1990s, astronomers made a surprising observation: not only is the universe expanding, but the rate of expansion is actually accelerating. This finding challenged the prevailing idea that gravity was the dominant force in shaping the expansion of the universe.
To explain this acceleration, scientists proposed the concept of dark energy. Dark energy is a hypothetical form of energy that fills the empty space of the universe and has a repulsive effect on gravity. It is believed to contribute to the accelerated expansion of the universe.
So, the observation of supernovae moving away at an accelerating rate serves as evidence for the existence of dark energy. By measuring the properties of these distant exploding stars, scientists have been able to determine that the expansion of the universe is accelerating rather than slowing down. This behavior is consistent with the presence of dark energy driving the accelerated expansion.