Nasa probe sees the ‘edge’ of our solar system for first time – and it’s completely different from what we thought
Nasa’s probes have seen the ‘edge’ of our solar system for the first time – and it’s completely different from what scientists thought.
Our solar system is flying through space more slowly than we thought – and Nasa’s IBEX – Interstellar Boundary Explorer – has found it doesn’t have a ‘bow shock’, an area of gas or plasma that shields our solar system as it hurtles though space
‘The sonic boom made by a jet breaking the sound barrier is an earthly example of a bow shock,’ says Dr. David McComas, principal investigator of the IBEX mission.
‘As the jet reaches supersonic speeds, the air ahead of it can’t get out of the way fast enough. Once the aircraft hits the speed of sound, the interaction changes instantaneously, resulting in a shock wave.’
But our solar system isn’t moving fast enough to generate a space version of a ‘sonic boom’.
For about a quarter of a century, researchers believed that the heliosphere moved through the interstellar medium at a speed fast enough to form a bow shock.
IBEX data have shown that the heliosphere actually moves through the local interstellar cloud at about 52,000 miles per hour, roughly 7,000 miles per hour slower than previously thought — slow enough to create more of a bow ‘wave’ than a shock.
‘While bow shocks certainly exist ahead of many other stars, we’re finding that our Sun’s interaction doesn’t reach the critical threshold to form a shock, so a wave is a more accurate depiction of what’s happening ahead of our heliosphere — much like the wave made by the bow of a boat as it glides through the water,’ says McComas.