A distant galaxy is emitting light from the helium spectrum at 388.9 nm. On Earth the wavelength of the light from this galaxy is measured to be 540.6 nm.
Estimate how far from Earth (in light-years) this galaxy is if the Hubble constant has the value 22 km/s per million light-years. (c = 3.00 108 m/s, 1 ly = 9.461 1015 m, 1 y = 3.156 107 s)
Question 2
If you take a given pendulum to the Moon, where the acceleration of gravity is less than on Earth, the resonant frequency of the pendulum will
A)
increase.
B)
decrease.
C)
not change.
D)
become zero.
E)
either increase or decrease; it depends on its length to mass ratio.
Changes in light quality with depth: (a) the rich colours on a shallow coral reef;
Comparative sizes of the Earth and the Moon
Stereo Image taken by NASA STEREO Probes launched in 2006; utilizing two Spacecrafts to image the Su
Light energy from the Sun powers
Short-wavelength flux is reflected by Earth
Earth Present