Alex McColgan

speaker

27,837 appearances 101 recordings 1 series first heard Nov 2024 last heard 5d ago

Alex McColgan’s voice in public audio — every appearance, attributed to the second.

Trend

recordings per month · last 12 months

Recordings per month over the last 12 months — 65 in all, peaking in Aug 2026 with 11.

Appearances

newest first · ▶ plays the moment

Astrum Space · We Thought It Was Impossible, But We’ve Finally Seen It · 31 Aug 2026 podcast

A collection of a few dozen neighbouring galaxies near to our own. voice-verified

Our local group belongs to a larger collection called the Laniakea supercluster, which contains some 100,000 galaxies and measures five hundred million light years across. voice-verified

As you might have guessed, all these galaxies are strung along the cosmic web like beads on strings perched along the edge of great voids. voice-verified

But even though we've been mapping this cosmic web for decades, most of what we can see is the beads, the distribution of galaxy clusters along the web, not the strings that hold them together or the filaments themselves. voice-verified

Or is it? voice-verified

Whilst most of the visible matter in the universe is tied up in galaxies, voice-verified

Not all of it is. voice-verified

The dark matter in the cosmic web has a pretty strong pull itself. voice-verified

There, bound up as vast diffuse gas in those long strings or filaments, is where large scale cosmological simulations have predicted we might not only find dark matter, but our missing visible matter too. voice-verified

This low density, diffuse gas is known as the warm hot intergalactic medium. voice-verified

But simulations are one thing, detecting these diffuse filaments is another. voice-verified

And this is where historically, we've not had much luck. voice-verified

Although that started to change about 20 years ago. voice-verified

In 2005, NASA's Chandra X-ray Observatory imaged two huge intergalactic clouds of diffuse gas. voice-verified

We'd seen clouds like this around our own galaxy and in others local to us, but not between distant galaxies. voice-verified

Could it be gas on the cosmic web? voice-verified

This was some of the first evidence that the cosmic web was hiding our missing mass. voice-verified

but the light was too faint to completely isolate it, so scientists couldn't quite be sure voice-verified

Then in twenty twelve a combination of eighteen Hubble images was used to infer the presence of a filament funneling matter into the galaxy cluster Max J0717. voice-verified

Scientists found it by studying the distortion of light from background galaxies due to the gravity of the filament's dark matter. voice-verified

Showing 1421–1440 of 27,837 · page 72 of 1392