Is the 'empty' space in our universe really empty? Here's what a new study found

The observable universe is about 93 billion light-years in diameter, and the entire universe is even bigger than anything we can imagine. Most of the space in the universe appears to be empty, but is it really though?

Now, we may have finally found the answer to this question. Here’s a look at what scientists say about how empty the ‘empty’ space really is.

Back in 1936, physicists Werner Heisenberg and Hans Euler proposed that in a strong enough magnetic field, the vacuum itself could bend light. This would then split it into two beams that travel at different speeds. It's called vacuum birefringence, and it suggests that space isn't truly empty even when no matter is present. 

But this idea stayed unproven for 90 years. Now, a new study on a magnetar, an extremely magnetic type of dead star, found signs that match that old prediction almost exactly. The researchers noted that in such fields, "different polarizations propagate at different speeds."

This reaction to magnetism is so weak that we can’t normally detect it in space. To actually catch it, we would need magnetic fields that are incredibly powerful (around 44 trillion gauss). For scale, Earth's own magnetic field is about one gauss. 

NASA points out that magnetars have magnetic fields "of about a million billion Gauss," adding that one "located a sixth of the way to the Moon...would wipe the data from all of the credit cards on Earth."

To see if the effect could actually be observed, scientists then studied the magnetar 1E 1547.0−5408 closely. This star spins once every two seconds. After combining different observations, the researchers found that its light stayed consistently polarized throughout its rotation.

This pattern suggests that the vacuum itself is affecting the light. The study noted that the results are “motivating further observational and theoretical studies concentrating on this domain.”

The Sun constantly sends out a stream of charged particles called the solar wind that reaches past Neptune. On the other hand, cosmic rays from distant stars travel through space. NASA shared that, while space is a vacuum, it's not 100% empty. This is because particles and even magnetic fields can travel through this void. 

This is also one of the things that astronauts in space need protection from. As per NASA, “Earth’s magnetic field and relatively thick atmosphere act as a shield against the most harmful forms of this radiation, but in space there is no such deterrent. If we want to travel through this space, we need ways to protect our astronauts.”