Magnetic field

When it comes to the discovery of radio signals coming from a planet in a distant solar system, you'd be forgiven for thinking that this could be the final... or, or I'm sorry, the first direct evidence of an advanced extraterrestrial civilization.

In actual fact, however, the signal in this particular case is not coming from an intelligent source, but the discovery could give astronomers a new way to identify and study magnetic fields on distant worlds, potentially helping them assess which planets might be habitable in the future.

The find, which was made by an international team of astronomers using South Africa's MeerKAT Radio Telescope array, consists of variable radio bursts originating from Beta Pictoris b, which is a gas giant exoplanet situated around a star 63 light-years away from the Earth.

The planet is particularly massive, around 12 times the mass of Jupiter.

[laughs]

Uh, the detection was made possible in part because Beta Pictoris, the star around which the planet orbits, is magnetically quiet, making it easier to distinguish the planet's radio emission.

This discovery is particularly interesting because planetary magnetic fields can help protect atmospheres from being stripped away by stellar winds.

There's a lot g- gets stripped away by stellar winds.

Conversely, a decrease in cosmic rays reduces cloud cover and produces relative warming.

Cosmic rays are charged particles so that flux reaching the lower atmosphere is modulated, deflected or reduced by the heliosphere, that's the sun's magnetic field and the solar wind, and by Earth's magnetosphere, Stronger solar activity expands and intensifies the heliosphere, shielding the Earth from more galactic cosmic rays, therefore fewer ions, fewer clouds, and therefore warming.

Weaker solar activity allows more cosmic rays through and more clouds and therefore cooling, effectively the opposite.

This provides a proposed amplification mechanism linking solar variability to climate that is stronger than changes in the total solar irradiance alone.

coming towards Earth, and you can see the magnetosphere.

You can see the Earth there, the smaller round circle there, and that's the magnetosphere.

And you've got the heliosphere, which is the solar wind and the magnetic field that engulfs the Earth.

And the...

Welcome to Tumble, the show where we explore stories of science discovery.

Today, we're talking about Earth's magnetic field.

Oh, I've heard of that field.

It's the one full of magnets that's on Earth.

[laughs] No, it's a magnetic force field that surrounds Earth, and it works just like any regular magnet you'll find on your refrigerator, and it's starting to pull us into its mysteries.

[upbeat music] Today, we have two questions about the Earth's magnetic field.

Well, before you go further, can you just explain what is the Earth's magnetic field, and is it just like a normal magnet?

Yeah, kind of.

I'm sitting down with Professors Jeffrey Guy and Alistair Nunn, who are the Founders and Chief Scientific Officer of the Guy Foundation, respectively.

And I've asked these gentlemen to join me to discuss magnetic fields and biology in the context of a recent seminar series that they hosted bringing together some experts on magnetobiology.

So maybe we can start with an open question and we can launch around, we can go right back around to the beginning by the end, I think, about how does magnetic fields, what role does this play in biology and potentially in human biology? disease.

So wherever you'd like to start with that.

Well, I think the good place is always to start is with history.

And certainly the fact that people actually for quite a long time realised that magnetic fields and electromagnetic fields were affecting biology.

But in particular, one place to look is navigation, bird navigation.

And I think that's the area everybody started to look at.

What happened then?

When the Voyager two spacecraft flew by Uranus in 1986 and Neptune in 1989, it made a really startling discovery about their magnetic fields.

Earth's magnetic field is relatively straightforward.

It aligns somewhat neatly with our north and south poles, and we know it's generated by the swirling liquid iron in our outer core.

But the gas giants are different, right?

Wildly different.

Voyager two found that the magnetic fields of Uranus and Neptune are chaotic and totally off-center.

Uranus' magnetic field is tilted fifty-nine degrees away from its rotation axis.

and wound up in Antarctica, where apparently meteorite hunting is easy, because you can see where the ice has been dented, and bring back the meteorite.

NASA has a huge collection of Some of them are very useful for hunting for magnetic fields.

Not all of them.

Grains inside some of the meteorites are from the beginning.

D-O-M.

Friendly.

Inside were grains made of calcium and other elements, consisting of calcium and other elements, that are excellent for finding magnetic fields.

They tested it and found it very strong, very strong, much stronger than the magnetic field we count on today.