Midterm 1 Key Facts Flashcards
What do lightyears mean about how we view the universe
We can see ‘back in time’
What is a light-year?
The distance that it takes for light to travel in one year
What is an Astronomical Unit (AU)?
The average distance between the earth and the sun
How fast is the speed of light in a vacuum?
3x10^8 meters per second
What is a photon?
A piece/particle of life
What does a longer frequency mean?
A longer wavelength
What does a longer wavelength mean?
Lower energy
At what temperature do stars appear blue?
Over around 10,000 Kelvin
At what temperature do stars appear red?
Below around 3,000 Kelvin
What is the surface temperature of the Sun?
Around 5,800 Kelvin
What is nuclear fusion?
The process of combining lightweight nuclei into heavier nuclei, releasing enough energy to supports stars against collapse from gravity
What does it mean when an atom is ionised?
when it loses/gains one or more electrons
What is the defining difference in different chemical elements?
They have different numbers of protons
Different isotopes have different numbers of what?
Neutrons
What is temperature?
The measurement of the average speed of the particles?