The scale of things and the view from the earth Flashcards
Who measured the circumference of the earth in 200BC
Eratosthenes
–1—- proposed a method to measure the distance to the Sun and the Moon in 280BC. Using how long it takes for the Moon to cross —2— shadow during —3–, he also tried to measure their sizes. He measured the —4— between the sun and the —5— or –6— quarter moon. Using these —7— and geometry, he calculated the —8– of the Earth-Sun distance and the —— - Moon distance.
1) Aristarchus
2)Earth’s
3)eclipses
From slide 9 picture, what is cos(theta) ?
Dm/Ds
Dm = distance to moon from earth
Ds = distance to sun from earth
The earth is –1– times bigger than the Moon
- 4 times
the sun is 400 times bigger than the —–
Moon
astronomical unit is
the average distance between Earth and Sun 1AU = 1.5*10^8
one Light-year is —–( 1 a sentence)—– and is approx. —-2—
1) Distance travelled by light in one year
2) 9.46MM km (mega *mega)
Parsec is a distance at which 1AU perpendicular to the —–1—- line of sight —–2—– an angle of 1 —-3—-
1)observers
2)subtends
3)arcsec
a theory is
a set of tested ideas written using math to try explaining how things behave
A hypothesis is
an idea or set of ideas
A model is
an idea written in math language and that can be tested via experiments
theory
Models that can explain
and predict behaviours
Laws - theories that —1—- be proved –2—
1)cannot
2)proved
if earth was flat, —– and —- will happen at the same for —— on Earth
1) daytime
2) nighttime
3)everyone
earth curves —- m every —- km
5m
8km