Which of the following best describes dark matter? (1 point) It’s an area that has become too concentrated with stars. O These are large clumps of galaxies. O It is very large and invisible, O Dark matter can only be detected using light beams
The Correct Answer and Explanation is:
Correct Answer:
It is very large and invisible.
Explanation
Dark matter is a mysterious substance that makes up about 27 percent of the universe, yet it cannot be seen directly. The term “dark” refers to the fact that it does not emit, absorb, or reflect light, making it invisible to telescopes and other instruments that detect electromagnetic radiation. Scientists know dark matter exists because of the gravitational effects it has on visible matter like stars and galaxies.
One of the key pieces of evidence for dark matter comes from observing how galaxies rotate. If only the visible matter were present, the outer stars in galaxies would rotate much slower than those near the center. However, observations show that the outer stars move just as fast, indicating that there must be additional unseen mass providing extra gravitational pull. This unseen mass is what scientists call dark matter.
Another clue comes from gravitational lensing, a phenomenon predicted by Einstein’s general theory of relativity. When light from distant galaxies passes near a massive object, such as a cluster of galaxies, the light bends. The amount of bending suggests more mass than can be accounted for by visible objects alone. This again points to the presence of dark matter.
Dark matter is not made of ordinary matter like protons and electrons. Instead, it is likely composed of particles that interact very weakly with ordinary matter, making it incredibly difficult to detect directly. Researchers use sensitive detectors in underground labs and observe cosmic phenomena to try to learn more about its nature.
Despite decades of research, the exact composition of dark matter remains unknown. However, its existence is widely accepted in the scientific community due to the overwhelming indirect evidence. Thus, the best description of dark matter is that it is very large and invisible, playing a crucial role in shaping the structure and behavior of the universe.
