Topic 10 Space

Question 1

In 2016 the Breakthrough Starshot initiative was announced. This project intends to send a fleet of small probes to Proxima Centauri, the nearest star to the Sun. This journey would take about twenty years.

Describe how the distance to nearby stars like Proxima Centauri is determined. (3)

Answer 1

-Star is viewed from two positions at 6 month intervals.
-The change in angle of star against fixed background distance stars measured.
-Trigonometry used to calculate distance to star.

Question 1

Describe the characteristics of a main sequence star. (2)

Answer 1

-Converting hydrogen to helium in their core (fusion).
-Maintain constant luminosity.

Question 2

Explain why the most massive stars in a young star cluster have the greatest luminosities. (4)

Answer 2

-Most massive stars experience much greater gravitational forces.
-So core temperature and density is greatest.
-Rate of fusion in core is greatest.
-Surface temperature is greatest.
-Surface area of these stars is greatest.

Question 3

State what is meant by a standard candle. (1)

Answer 3

-Object of a known luminosity.

Question 4

Describe how distances too large for the use of standard candles can be determined. (3)

Answer 4

-Measure change in wavelength/frequency.
-Determine velocity using redshift formula.
-Then apply V=H0d.

Question 5

A source of sound of constant frequency is moving towards an observer. Compared to the frequency of the source, the frequency of sound heard by the observer is. (1)

Answer 5

-Higher, because the wavelength of the sound decreases.