According to observations, which type of galaxy was much more common when the universe was 2 billion years old than it is today?
A) irregular galaxies
B) elliptical galaxies
C) spiral galaxies
D) We can't say because humans were not alive at that time.
A) irregular galaxies
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Due to the first strong commercial radio stations, our radio presence is now known out to over about 70 light years
Indicate whether the statement is true or false
A proton with mass 1.67 × 10^?27 kg moves in an accelerator with a speed of 0.780c. What is its total energy? (c = 3.00 × 10^8 m/s)
a. 1.50E–10 J b. 3.90E–10 J c. 2.40E–10 J d. 7.51E–19 J e. 1.28E–18 J
When a magnetic field causes a charged particle to move in a circular path, the only quantity listed below which the magnetic force changes significantly as the particle goes around in a circle is the particle's:
a. energy. c. momentum. b. time to go around the circle once. d. radius for the circle.
The biggest obstacle to life being present in the atmospheres of Jupiter and Saturn is the
A) absence of liquid water in their atmospheres B) high levels of solar radiation that would destroy any biological molecules C) strong vertical wind speeds that would rapidly carry organisms into the hot interior where they would be destroyed D) very low temperatures at the tops of the clouds where water would not be liquid