What is the parallax angle for Proxima Centauri, which is Earth's nearest star at 4.3 ly?
The earth's orbit has a mean radius of 1.5 108 km, and 1 ly = 9.46 1015 m.
A) 1.2 10-7 degrees B) 2.1 10-7 degrees
C) 1.2 10-14 degrees D) 2.1 10-4 degrees
Question 2
A light source radiates 60.0 W of single-wavelength sinusoidal light uniformly in all directions. What is the amplitude of the electric field of this light at a distance of 0.400 m from the bulb?
(0 = 8.85 10-12 C2/N m2, 0 = 4 10-7 T m/A, c = 3.00 108 m/s)
A) 162 N/C B) 52.9 N/C C) 212 N/C D) 150 N/C E) 82.1 N/C
Changes in Earth's atmospheric carbon dioxide levels over geological time.
Animation of the apparent retrograde motion of Mars in 2003 as seen from Earth
Earth’s Heat Budget
Earth’s Mineral Resources
Earth-Moon-Sun Positions during the Neap Tide
Relative Sizes of Dwarf Planets and Earth