Astronomy Cast - Ep. 76: Lagrange Points

Ep. 76: Lagrange Points

Joseph-Louis Lagrange credit: ESA

Gravity is always pulling you down, but there are places in the solar system where gravity balances out. These are called Lagrange points and space agencies use them as stable places to put spacecraft. Nature is on to them and has already been using them for billions of years.

Episode 76: Lagrange Points (13.2MB)

Ep. 73: Questions Show #8

Listener Questions Show credit: Rebecca B-F

We’ve been so crazy following our own whims through the universe that we’ve neglected your questions. That ends today. It’s time to dig deep into our overflowing email box to retrieve the puzzling questions our listeners have sent in.

Episode 73: Questions Show #8 (16.8MB)

Ep. 48: Tidal Forces Across the Universe

The gravity of the two colliding antennae galaxies creates the impressive tidal tails. credit: copyright Daniel Verschatse (Antilhue Observatory)

Last week we talked about tidal forces within our solar system. This week we're going to expand our view and encompass the entire universe. Some of the most dramatic events originate from tidal forces caused by gravity: other worlds, galaxies, black holes and even entire clusters of galaxies are under this influence.

Episode 48: Tidal Forces Across the Universe (12.2MB)

Ep. 47: Tidal Forces

The force of gravity can cause comets like Shoemaker-Levy 9 to rip apart credit: H. Weaver (JHU), T. Smith, NASA

Consider the following: we've got tides here on Earth, the Moon only shows one face to the Earth, we've got volcanoes on Io, and ice geysers on Enceladus. All these phenomena originate from a common cause: the force of gravity stretching across space to tug at another world.

Episode 47: Tidal Forces (13.4MB)

Ep. 42: Magnetism Everywhere

Coronal mass ejections occur when solar magnetic field lines snake around each other - but the Sun is not the only object with a magnetic field credit: NASA/MSFC

You probably don't realise it, but magnetic fields are everywhere. We're not talking about the magnets in your speakers, your electronic equipment or on the fridge door. We're talking about the gigantic magnetic fields that surround planets, stars, galaxies and some of the most exotic objects in the Universe.

Episode 42: Magnetism Everywhere (13.5MB)

Ep. 11: A Universe of Dark Energy

Components of the Universe credit: NASA/CXC/M.Weiss

The discovery of dark energy was one of the biggest surprises in astronomy. Instead of a nice, predictable expanding Universe, acted on only by gravity, astronomers turned up a mysterious repulsive force accelerating the expansion of the Universe. Fraser and Pamela explain
the evidence for a dark energy, and a few possible theories for what could be providing this repulsive force.

Download Episode 11: A Universe of Dark Energy (13 MB)