The Earth is a satellite, a satellite that’s not only in orbit around the Sun but is also in orbit with the Sun, so it’s actually pretty small.
And yet the Earth’s magnetic field is still around, which is why the Earth can still be measured.
Now scientists at the University of Oxford have managed to measure the Earth-tuning instrument (ETI), a device that measures the Earth as a sphere around a centre.
The ETI is about the size of a coffee mug, and it has a very narrow magnetic field, just about half the diameter of a human hair.
The researchers are keen to see how it responds to the magnetic field changes around the globe.
It’s currently only used in Australia, but in the future, the researchers say, they expect to use it in the Arctic, and in Antarctica.
Scientists have long known that the Earth is actually an extremely thin sphere, measuring just 0.07mm in diameter.
But until now, there has been little work done to understand how the Earth responds to different types of magnetic fields.
“It’s important to understand the magnetic fields around the Earth because it affects the magnetic poles of the Earth, which are where magnetic fields are strongest,” Professor Simon D’Odorico, a co-author on the paper, said.
And the new work looks at the changes in the magnetic polarity of the magnetic pole in the Earth over time.
What we found was that the magnetic strength of the north pole was the strongest in the northern hemisphere during the last 800 million years, and then it got weaker as the ice ages and glaciers receded.
But when we looked at the magnetic strengths in the polar regions, they all fell off, which indicates that the polar poles are still very strong.
“This means that the north and south poles are connected by a very thin magnetic field and are not connected at all,” Professor D’Osorico said.
The magnetic field in the north has been decreasing since about 2.5 billion years ago, so this implies that the planet is getting hotter, and that the changes to the polar magnetic field have affected the Earth.
But how did the Earth get so hot?
“The first theory is that the heat is coming from the Sun,” Professor Richard Gans, a PhD student at the time and the paper’s first author, said in a statement.
“It’s possible that we are now approaching a point in the solar system where we’re getting hotter and hotter.”
It’s likely that the warming is caused by an imbalance in the Sun’s energy output, which can change the magnetic properties of the planet.
Professor Gans said that although the magnetosphere was a key component of the magnetism of the entire planet, it was not the only thing that was changing, and this imbalance was affecting the Earth too.
“If you look at the current state of the atmosphere, it’s probably very good at reflecting some of the solar energy, but it’s also absorbing some of it,” he said.
“So that’s a major source of heating.”
Professor Gins also said that the study’s findings should give astronomers an insight into the processes at work in the core of the Solar System.
“[It] will give us a clue about what’s happening at the centre of the Sun and also help us understand how much energy there is in the Solar Core,” he added.
“What’s really interesting about this is that it doesn’t mean that the Sun is the source of the heating that we’ve seen.”
“This work is a step forward in understanding how our Solar System formed, and is also important to understanding the Earth system around us,” Professor Gans concluded.
You can read the paper in the journal Nature Geoscience.