astronomy lecture 2

what is the nearest star

proxima centauri

how far away is proxima centauri in miles

2.47×10^13 miles

what is the size of a hydrogen atom in miles

6.6×10^-14 miles

kilo

10³

mega

10^6

giga

10^9

centi

10^-2

milli

10^-3

micro

10^-6

nano

10^-9

what is absolute zero

the lowest temperature possible, where all motion stop

what is zero kelvin in Fahrenheit and Celsius

-459F and -273C

speed of light equation

c= 3×10^5 km/s (300,000)

how is distance relative to speed and time (equations)

distance = speed x time

how long for the moon to reach us at light speed

1.3 seconds

how long for the sun to reach us at light speed

8.3 minutes

how long for the pluto to reach us at light speed

5.3 hours

how long for the Proxima Centauri to reach us at light speed

4.2 years