Galaxies, Science How do you measure the rotational speed of a galaxy, taking into consideration the motion of our galaxy, solar system, planet, etc.?
Human Spaceflight I’ve read that the planned crewed Mars missions will take six months or two years to arrive. Which is it? could a longer trip be due to the heavy payload? Our rovers took only eight to nine months to arrive.
Observing How large does the Sun appear from Mercury and Venus, as compared to how we see it from Earth?
Solar System I’ve heard that the Oort Cloud contains trillions of icy bodies. What would be the average distance between these bodies?
Science In the November 2017 issue’s gravitational waves story, Robert Naeye wrote, “If gravitational waves disperse, slower frequencies will arrive at the detectors after the faster ones.” But how are there different velocities for different frequencies? It seems illogical to me.
Solar System, Stars My understanding is that the materials for our solar system and others nearby were created by a supernova. Where is the black hole from that supernova?
