09-28-2025

Huge space bubble called the 'heliosphere' allows life to exist on Earth, and we know every little about it

ByEric Ralls

Earth.com staff writer

An extraordinary structure called the “heliosphere” envelops our entire solar system in a protective bubble. NASA’s new mission, IMAP, will get close enough to the Sun to investigate how the heliosphere works.

Inflated by the Sun, the heliosphere shields Earth and our planetary neighbors from deadly cosmic radiation that travels at the speed of light, allowing life on this beautiful blue marble to survive and thrive.

How the Sun fuels the heliosphere

The Sun is constantly emitting bursts of charged particles – protons, electrons, and ions – at speeds of more than a million miles per hour.

This colossal stream, which is referred to as the solar wind, fills out the heliosphere and sets it ballooning billions of miles outward.

Earth has its own protection too – our magnetic field – but that only covers our planet. For everything else in the solar system, the heliosphere takes on the heavy lifting.

NASA’s IMAP to study the heliosphere

The Interstellar Mapping and Acceleration Probe – IMAP for short – launched onboard a SpaceX Falcon 9 rocket on September 24, 2025, from Kennedy Space Center in Florida.

IMAP will now spend two years collecting data about the heliosphere, the solar wind, radiation, magnetic fields, and other space weather conditions.

One of the scientists playing a big role in IMAP is William H. Matthaeus, a physicist from the University of Delaware who specializes in the Sun’s magnetic field and solar wind. His work helped design the magnetic field instrument onboard IMAP.

The mission’s main questions are: How do those solar particles gain so much energy? And how exactly does our solar system interact with the wider galaxy?

IMAP carries 10 different instruments to help answer those questions. It’ll also study tiny particles called cosmic dust, which come from beyond the solar system.

“That all relates to space weather. If you want to know what’s hitting Earth, you have to have spacecraft in the right position. That’s always of interest from a space weather point of view,” Matthaeus explained.

“You get to understand how significant the perturbations are when they come by. That’s important if you want to design missions to better withstand the conditions and see conditions farther from the sun.”

It’s also essential for keeping future astronauts safe as they head to the Moon or Mars.

Where IMAP will park

This isn’t just a science experiment for fun. Space weather affects real things here on Earth – like satellites, radio communication, power grids, and even the safety of astronauts.

IMAP will park at a spot called Lagrange Point 1, or L1 for short. That’s about 1 million miles (1.6 million kilometers) from Earth, in the direction of the Sun.

It’s a perfect spot for observing space weather because gravity from the Earth and Sun balance out there.

Two other spacecraft will tag along with IMAP. One is the Carruthers Geocorona Observatory, the first mission focused on changes in Earth’s outermost atmosphere.

The other is NOAA’s Space Weather Follow On L1, which will track the solar wind and coronal mass ejections – huge eruptions of energy from the Sun’s surface that can disrupt life on Earth.

More spacecraft, more discoveries

L1 isn’t empty. It’s already home to five other spacecraft, and Matthaeus is excited to add some more.

“That’s one of the specialties of our group. And IMAP is going to add another spacecraft to the L1 fleet, what I like to call the ‘L1 constellation,’” he said.

Other spacecraft near L1 include Ace, Wind, Discover, MMS, and India’s Aditya. There will be at least six spacecraft available simultaneously.

“You can’t measure three dimensions with one spacecraft. And even with two, you only get one direction. Now we’ll have information about the three-dimensional structure of shocks, coronal mass ejections and turbulence,” Matthaeus noted.

How IMAP will see the heliosphere

IMAP will also be able to do something special: detect energetic neutral atoms heading for Earth.

These atoms are unique because they don’t have a charge, which means they aren’t affected by magnetic fields. They travel in straight lines, making it easier to figure out where they came from.

IMAP has three instruments just for detecting these particles, and they’ll help scientists map the heliosphere and parts of space we’ve never understood before.

This isn’t just about measuring numbers though. It’s about figuring out how our solar system works – and how it connects to the galaxy around us.

“We are going to find incredible new discoveries,” said Nicky Fox, associate administrator for NASA’s Science Mission Directorate.

“What is coming from the sun? What is coming from the interstellar medium? We’re excited about the applications. But the actual discovery science is going to literally rewrite textbooks and that’s why we’re so excited about it.”

Matthaeus added that, “We intend to be part of that rewrite – not just me, but my students and postdocs. I always tell them, ‘Don’t just look over your shoulder. Try to do something nobody else has done before.”