Question

earth and space: 2025/6
name/block hand - written text

short answer

1. how old is the universe?
2. explain the red - shift / blue - shift in visible light frequency of the visible light spectrum and how it acts as evidence for the way the universe is acting.
3. how do we measure distances in space?
4. roughly how many stars are in our galaxy?

a. 10,000 - 100,000
b. 10,000,000 - 100,000,000
c. 100,000,000 - 400,000,000
d. 100,000,000,000 - 400,000,000,000

1. true or false: all stars are the same size.
2. name 3 problems faced by the apollo 13 crew

Explanation:

1. Current scientific estimates suggest the universe is about 13.8 billion years old, based on cosmic microwave background radiation and other cosmological data.
2. Red - shift occurs when an object is moving away from an observer, stretching the light waves to longer wavelengths (towards the red end of the spectrum), indicating the expansion of the universe. Blue - shift is when an object is moving towards an observer, compressing the light waves to shorter wavelengths (towards the blue end).
3. In space, distances can be measured using methods like parallax for nearby stars, standard candles (such as Cepheid variables and Type Ia supernovae) for more distant objects, and redshift - distance relationships.
4. Our galaxy, the Milky Way, is estimated to contain about 100 - 400 billion stars. So the answer is c. 100,000,000 - 400,000,000.
5. False. Stars vary greatly in size, from small red dwarfs to large supergiants.
6. The Apollo 13 crew faced problems such as an oxygen tank explosion, loss of power, and difficulties with carbon dioxide removal and navigation.

Answer:

1. Approximately 13.8 billion years.
2. Red - shift indicates objects moving away (universe expansion), blue - shift indicates objects moving towards.
3. Parallax, standard candles, redshift - distance relationships.
4. C. 100,000,000 - 400,000,000
5. False
6. Oxygen tank explosion, power loss, CO2 removal issues.