QUIZ - 5.14.13

1. Will the universe continue expanding forever?

• Current measurements indicate that there is not enough dark matter to prevent the universe from expanding forever.

2. Is the expansion of the universe accelerating?

• An accelerating universe is the best explanation for the distances we measure when using white dwarf supernovae as standard candles.

3. What discovery received the Physics Nobel Prize in 2011?

• The Nobel Prize in Physics 2011 was divided; one half awarded to Saul Perlmutter, the other half jointly to Brian P. Schmidt and Adam G. Reiss "for the discovery of the accelerating expansion of the Universe through observations of distant supernovae."

4. Name the three scientists that received the prize?

• The three scientists that received that prize were Saul Perlmutter, Brian P. Schmidt, and Adam G. Reiss.

5. Which standard candles were used to measure the acceleration of the universe?

• The research teams looked for a certain type of supernova, called a SUPERNOVA 1A, which happens when a white dwarf star gains enough extra matter to make it unstable. This sort of supernova is so powerful that it can outshine even a galaxy. Since we understand this sort of supernova well, it can be used as a "standard candle" to measure the distance to the supernovas & this measurement can be used to calculate the expansion rate of the universe over time.

6. What are the fractions of baryonic matter, dark matter, and dark energy?

• The fraction for both baryonic matter and dark matter is 27.4%. The fraction for dark energy is 71.3%.

7. Describe Figure 16.16 of the textbook.

• The figure in 16.16 of the textbook is four possible models for the expansion of the universe. Each individual curve is shown how the average distance between galaxies changes with time for a particular model.

8. Which model fits best?

• The model that fits best and is greatest at presenting/explaining the accelerating universe to us would be the supernova data model.

9. According to this model, which is the age of the universe?

• According to this model, the age of the universe is 14 billion years old.

10. Is there something opposing gravitational attraction in the universe as a whole?

• Yes, there is something opposing gravitational attraction in the universe as a whole and that would be dark matter.