How has scientific understanding about the composition of the universe changed over time? Select the two correct answers.(1 point) Responses The percentage of ordinary matter has grown in scientists' estimates. The percentage of ordinary matter has grown in scientists' estimates. The percentage of dark energy has shrunk in scientists' estimates. The percentage of dark energy has shrunk in scientists' estimates. The percentage of unknown material has grown in scientists' estimates since the 1970s. The percentage of unknown material has grown in scientists' estimates since the 1970s. The percentage of dark matter has shrunk in scientists' estimates since the 1980s.
The correct answers are:
- The percentage of ordinary matter has grown in scientists' estimates.
- The percentage of unknown material has grown in scientists' estimates since the 1970s.
How did dark matter affect the development of structures in the early universe?(1 point) Responses It became part of black holes. It became part of black holes. It seeded the development of galaxies. It seeded the development of galaxies. It seeded the development of quasars. It seeded the development of quasars. It cooled pockets of gas to form nebulae.
The correct answer is: "It seeded the development of galaxies."
Which is evidence for the existence of dark energy?(1 point) Responses Supernovae that are moving away at an accelerating rate. Supernovae that are moving away at an accelerating rate. Black holes that are expanding at a constant rate. Black holes that are expanding at a constant rate. Pulsars that seem to be moving closer at an accelerating rate. Pulsars that seem to be moving closer at an accelerating rate. Galaxies that are rotating at a constant rate.
The correct answer is: "Supernovae that are moving away at an accelerating rate."
The two correct answers are:
1. The percentage of ordinary matter has grown in scientists' estimates.
2. The percentage of dark energy has shrunk in scientists' estimates.
The correct answers are:
1) The percentage of dark energy has shrunk in scientists' estimates.
2) The percentage of dark matter has shrunk in scientists' estimates since the 1980s.
To determine these answers, scientists have been studying the composition of the universe using various observational techniques and theoretical models. Over time, our understanding of the composition of the universe has evolved.
In the 1990s, astronomers discovered that the expansion of the universe is accelerating, which led to the hypothesis of dark energy. Initially, scientists estimated that dark energy makes up about 70% of the total mass-energy content of the universe. However, further research and observations have led to a revision of this estimate, suggesting that dark energy may make up a slightly smaller percentage.
Similarly, the concept of dark matter was proposed to explain the gravitational effects observed in galaxies and galaxy clusters that cannot be accounted for by visible matter. Initially, scientists estimated that dark matter makes up about 25% of the total mass-energy content of the universe. However, further investigations and improved measurements have led to a reassessment of this estimate, indicating that dark matter may constitute a smaller percentage.
Therefore, the correct answers are that the percentage of dark energy and dark matter has shrunk in scientists' estimates over time.