Episode 16: Einstein at the Heart of the Galaxy

Episode 16: Einstein at the Heart of the Galaxy

There’s a monster deep in the heart of the Milky Way Galaxy. Even though we can’t see it, we know it’s there ... because it has to be.

Over two decades, astronomers have pointed very large telescopes, including The Very Large Telescope, toward the galactic centre. They’ve been tracking the motions of a bunch of stars right at the core — ordinary stars doing something extraordinary. They’re moving fast, very very fast, in orbit around something very massive. But when astronomers look to find what’s at the centre of these stars’ orbits ... there’s nothing there.

The only real possibility is that they are orbiting a super-massive black hole.

At their fastest, some of the stars are moving at a few percent of the speed of light, which is fast enough to put Einstein’s theory of relativity to the test. 

Episode 15: A Salty Lake on Mars

Episode 15: A Salty Lake on Mars

Stop me if you've heard this one before: astronomers announced in July that they'd found water on Mars.

No, seriously. I know they've said something that sounds like that before, but this is different — this is *liquid* water. Probably.

See, previously they'd found solid ice, and then found evidence for liquid water billions of years in the past, and then signs that sometimes a little bit of water runs across the surface in the Martian summer before evaporating away. But *this* time, astronomers reckon they've spotted a lake of briny water down under the surface. Which is exciting — so, could it mean life?! Hmmmm.

Episode 14: Total Eclipse of the Moon

Episode 14: Total Eclipse of the Moon

Around 9pm (local UK time) on Friday 27 July 2018, the full moon will rise over the horizon. But this full moon will be a bit special: it’ll be a deep red colour, because we’re going to experience a total lunar eclipse! C’mon people, get outside!

A lunar eclipse is where the Moon passes through the Earth’s shadow. That means the Moon, the Earth and the Sun are aligned. We have a word for that: it’s totally going to be a syzygy!

So to celebrate, we’re chatting about the eclipse — what it will look like, when to watch it, where the redness comes from — as well as getting a bit lost in tangents along the way, as we do, about astrology, the end of the world, Betteridge’s Law of Headlines and cosmic  sows.

Episode 13: Neutrino Messenger from a Distant Blazar

Episode 13: Neutrino Messenger from a Distant Blazar

In September 2017, two kilometres deep beneath the South Pole, a tiny but very speedy neutrino collided with an atom in the ice and created a flash of light. The flash was picked up by a few of the more than 5,000 photodetectors that comprise the IceCube Neutrino Observatory, and immediately the banks of computers at the surface sent out an alarm to astronomers across the globe: we’ve found one!

Astronomers pointed their telescopes back along the neutrino’s path, and searched for a source. Eventually they found one: an exotic entity known as a blazar, a supermassive black hole at the core of a galaxy 3.7 billion light years away, spewing out an intense beam of high-energy particles that happens to be pointing right at us.

A single neutrino, heralding an exciting new era of multi-messenger astronomy.

Episode 12: The Light Fantastic

Episode 12: The Light Fantastic

A question from a listener leads us into some very tall weeds as we ponder the nature of light: what is it, exactly? It is a wave? Or a particle? Or, somehow, both at once? And photons, the massless particles that apparently make up all light: if they've got no mass, how can they be affected by gravity — like around a black hole, for example? Oh, it's all very tricky stuff, but we have lots of fun unpacking it all. Because in the end, you can't do much astronomy without light, so it's best to understand it properly, really.

Episode 11: Black Hole Eats Star, Then Burps

Episode 11: Black Hole Eats Star, Then Burps

Black holes: a staple of quality science fiction for decades now ... but what actually *are* they? Awesome, is one answer. Astronomers reported a few weeks ago fresh evidence for a black hole tearing a star apart in a distant galaxy — gruesome, sure, but fascinating too. In this eipisode we chat about black holes and come to the conclusion that they warp our brains like the fabric of space-time itself.

Episode 10: So you want to be an astronomer?

Episode 10: So you want to be an astronomer?

It's episode 10! We celebrate with cake and a chat about how how astronomers become astronomers. Emily describes her (slightly unusual and a bit cheeky) path to her current career as Astronomer Extraordinaire and Director of the University of York's Astrocampus. Then we explore all the different skills and job titles that fall under the broad umbrella of "working in Astronomy". And of course, even if you don't want to do it as a job, there's a very long and distinguished history of amateur astronomy to discover. Really, there's no reason *not* to get involved.

Episode 09: Life on Mars?

Episode 09: Life on Mars?

A few weeks ago NASA gathered journalists from across the globe for an announcement about something they'd found on Mars. Naturally, the collective imagination went *nuts*, because surely, SURELY this was going to be The Big Announcement: finally, the discovery of Life Elsewhere In The Universe! Turns out, nope ... but NASA did have some very cool things to talk about. Curiosity, the Mars Rover that just keeps on keeping on, has found seasonal changes in methane levels, which *could* be produced by biological mechanisms. It also found a bunch of interesting organic molecules in the martian soil. Neither of these discoveries say that life ever existed on Mars, but they're both tantalising whispers urging us to keep looking, keep looking ...

Episode 08: The Frozen Dunes of Pluto

Episode 08: The Frozen Dunes of Pluto

At the XXVIth General Assembly of the International Astronomical Union, held in Praague in August 2006, a new set of three criteria were decided to define what is — and what is emphatically *not* — a planet. Infamously, Pluto fulfilled only two of the three criteria, and so was unceremoniously dumped from the planet club, and reclassified as a "dwarf planet". A decade later, the New Horizons spacecraft swung past this tiny, frozen rock on the outskirts of the Solar System and reported back that Pluto is actually a pretty fascinating place, with a loads of cool suface features and even a thin atmosphere capable of creating dunes of solid methane! Dwarf planet it may be, but Pluto is still awesome.

Episode 07 (supplemental): Octopuses from Space!

Episode 07 (supplemental): Octopuses from Space!

So, apparently, octopuses come from space. Or something. Emily and Chris chat about a ... curious ... paper that came out recently, which proposes an explanation for the Cambrian Explosion, the huge increase in diversity of life across the planet 500 million years ago. The suggested cause? Possibly viruses from space ... possibly octopus eggs in a meteor ... oh, who knows? It all seems a tad speculative but it's fun to discuss anyway.