Feeds

Voyager 1: exit stage left

Humanity goes interstellar

  • alert
  • submit to reddit

Build a business case: developing custom apps

Voyager 1 has officially left the solar system, having crossed the so-called termination shock in December last year. The craft crossed the boundary 94 astronomical units (the distance from the Earth to the sun is one AU) from the sun, according to NASA researchers based in Washington DC.

The key things to look for, scientists say, are an abrupt drop in the speed of the solar wind, along with a significant increase in the sun's magnetic field strength. The solar wind loses speed quickly at the termination shock, falling from at least 700,000 miles per hour down to 100,000mph.

Based on the strength of the solar wind, some researchers claimed Voyager passed this marker three years ago. But because there was no change in the magnetic field strength - caused by solar particles slowing down and crowding together at the termination shock - the claim was widely disputed.

On this occasion, Voyager 1's magnetometer has detected a two-and-a-half fold increase in the strength of the magnetic field, New Scientist reports. The researchers have ruled out the possibility that this is due to a solar flare's shock front. If a solar flare was behind the increase in the magnetic field strength, the craft would also have detected fewer cosmic rays, but instead the reverse is true.

Edward Stone, of Caltech told New Scientist: "This time the entire Voyager 1 team agrees we have crossed the termination shock."

However, there is still missing data. Theory predicts that Voyager should have seen an increase in so-called anomalous cosmic rays (ACR) when it left the solar system, but no such increase was detected.

ACRs are bits of neutral interstellar flotsam that are ionised when they enter the solar system. The Voyager 1 team proposes that ACRs might be made only in especially turbulent parts of the termination shock, as opposed to continuously along its edge. If this is the case, it is possible that Voyager just missed them. ®

Related stories

Sun spits out tiny squirt of plasma
Green light for tests on really big telescope designs
Europe will land on Mars in 2013

Securing Web Applications Made Simple and Scalable

More from The Register

next story
Asteroid's DINO KILLING SPREE just bad luck – boffins
Sauricide WASN'T inevitable, reckon scientists
BEST BATTERY EVER: All lithium, all the time, plus a dash of carbon nano-stuff
We have found the Holy Grail (of batteries) - boffins
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
Famous 'Dish' radio telescope to be emptied in budget crisis: CSIRO
Radio astronomy suffering to protect Square Kilometre Array
Bad back? Show some spine and stop popping paracetamol
Study finds common pain-killer doesn't reduce pain or shorten recovery
Forty-five years ago: FOOTPRINTS FOUND ON MOON
NASA won't be back any time soon, sadly
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.