How has scientific understanding about the composition of the universe changed over time? Select the two correct answers.(1 point)
Responses
The percentage of dark energy has shrunk in scientists' estimates.
The percentage of dark matter has shrunk in scientists' estimates since the 1980s.
The percentage of unknown material has grown in scientists' estimates since the 1970s.
The percentage of ordinary matter has grown in scientists' estimates.
The two correct answers are:
1. The percentage of unknown material has grown in scientists' estimates since the 1970s.
2. The percentage of ordinary matter has grown in scientists' estimates.
To determine which answers are correct, we need to look at how scientific understanding of the composition of the universe has evolved over time.
1. The percentage of dark energy has shrunk in scientists' estimates: This answer is incorrect. In fact, scientific understanding has shown that dark energy makes up about 68% of the universe, and its existence was not even discovered until the late 20th century.
2. The percentage of dark matter has shrunk in scientists' estimates since the 1980s: This answer is correct. Initially, dark matter was believed to be a significant component of the universe, accounting for a large percentage of its mass. However, as more research and observations have been conducted, scientists have revised their estimates, suggesting that dark matter makes up about 27% of the universe, lower than previous estimates.
3. The percentage of unknown material has grown in scientists' estimates since the 1970s: This answer is correct. The term "unknown material" refers to the components of the universe that have not been identified or understood yet. Over time, scientists have realized that a substantial portion of the universe is made up of this mysterious, unidentified material. It is often referred to as "dark matter" and "dark energy."
4. The percentage of ordinary matter has grown in scientists' estimates: This answer is incorrect. Ordinary matter, which includes everything made up of atoms such as stars, planets, and galaxies, is estimated to make up only about 5% of the universe. This percentage has not seen a significant change in scientific estimates over time.
Therefore, the correct answers are:
- The percentage of dark matter has shrunk in scientists' estimates since the 1980s.
- The percentage of unknown material has grown in scientists' estimates since the 1970s.
The two correct answers are:
1. The percentage of dark energy has shrunk in scientists' estimates.
2. The percentage of ordinary matter has grown in scientists' estimates.