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
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 supernovae that are moving away at an accelerating rate. This observation suggests that the expansion of the universe is not slowing down as expected due to the gravitational pull of matter, but instead, it is accelerating. This phenomenon is thought to be driven by dark energy, a mysterious form of energy that permeates space and counteracts the gravitational force of matter, causing the accelerated expansion.
The evidence for the existence of dark energy comes from observing the motion and behavior of distant celestial objects, particularly galaxies and supernovae. Out of the options you provided, the evidence that supports the existence of dark energy is "Supernovae that are moving away at an accelerating rate."
To explain how scientists arrived at this conclusion, we need to consider the concept of redshift. When light from distant objects, such as supernovae, travels through space, the expansion of the universe causes the wavelength of the light to stretch out. This stretching of the light is known as redshift.
By studying the redshift of light from distant supernovae, scientists discovered that their redshift is greater than what would be expected based on their distance. This observation indicates that the supernovae are actually moving away from us at an accelerating rate.
Since gravity tends to slow down the expansion of the universe, this faster-than-expected expansion suggests the presence of a mysterious force counteracting gravity, known as dark energy. Dark energy is believed to be responsible for the accelerating expansion of the universe.