# Fall SAVY 2017, Day 4- Journey into the Universe: Astronomy 101 (3rd/4th)

Posted by on Monday, October 16, 2017 in Grade 3, Grade 4, SAVY.

Today was an active day in Planetary Astronomy!

First, we reviewed a little about orbits from last week (circular, elliptical, hyperbola (a.k.a. ByeBye orbit!)) and then started talking about WHY orbits look that way and the cause of gravity. We did look at the equation for gravity (an algebra equation) and the students liked that. Note that we’re looking at orbits and the cause of them because planets and moons and asteroids and comets are all orbiting stars, stars are orbiting the centers of galaxies, and so we need to understand orbits to understand planetary science.

Anyway, the cause of gravity and how orbits behave is the curvature of spacetime (otherwise known as General Relativity). One of the extremes of the curvature of spacetime is a black hole so we of course had to discuss those. Talk to your student about 3-dimensional (example 1, example 2) versus 2-dimensional representations and also about how you can die going into a black hole 😉
For further information about spacetime and orbits, check out this YouTube video: Gravity – From Newton to Einstein – The Elegant Universe
For further information about black holes, here’s a nice overview video: Black Hole

After our break, we started our experiments with models of spacetime! We used hula hoops, swimsuit material, and binder clips to simulate two-dimensional spacetime. Then I provided the students with weights of different kinds for central masses and for orbiters. Students had to make different kinds of orbits and engage in experiments to see how orbits behave in the spacetime world.

Here are some examples of such models: Spandex Gravity Well from U of Toledo; Operation Spandex from the Society of Physics Students, and Brian Greene Explores General Relativity in His Living Room

I hope you enjoy learning about spacetime as much as the students did today!

– Dr. G 🙂