Nasa confirms that the Voyager 1 probe has entered interstellar space (again)

The spacecraft has travelled further from Earth than any other man-made object in existence, despite confusion over what constitutes ''interstellar space'

After travelling for longer than 36 years and covering a distance of nearly 12 billion miles, the space probe Voyager 1 has finally entered interstellar space, according to a new report from Nasa.

The craft was launched in 1977 as part of a long-term mission to study the solar system, and after conducting flybys of both Jupiter and Saturn was set on a course straight out the solar system carrying images of Earth and a Golden LP with a track list of humanity's greatest hits.

Read more: What images and music is Voyager 1 taking to the stars?

The problem, however, is that Voyager 1 has already entered interstellar space – at least according to some reports, with the probe making headlines last year when scientists declared that it had left the heliosphere back in August 2012.

The heliosphere is the mammoth ‘bubble’ that marks the boundaries of the Sun’s magnetic influence and for many astronomers it’s as good a marker as any for what constitutes the beginning of interstellar space.

Objects within the heliosphere are affected by solar wind (the streams of plasma shot out by the sun) while anything in interstellar space is influenced primarily by the ‘interstellar medium’ – a hotchpotch of matter and energy that includes various forms of gasses, dust and cosmic rays. The uncertain borders between these regions are known as the heliosheath.

An illustration showing the path of the two Voyager spacecraft. Image credit: Nasa/JPL/Caltech

As you’d imagine, determining which side of the heliosheath Voyager 1 is on is pretty tricky, something akin to wandering along the Scottish-English border with your eyes closed and trying to work out which country you’re in by tasting the rain.

So what makes scientist so sure this time round? It’s all thanks to a recent tsunami of plasma released by the Sun. These cosmic events - which are expected, if not predictable - create shock waves that ripple through solar system and into the interstellar matter, and leave the Voyager 1 probe bobbing like a buoy after a ship has passed by.

"Normally, interstellar space is like a quiet lake," said Ed Stone of the California Institute of Technology, Voyager 1’s lead scientist since 1972. “But when our sun has a burst, it sends a shock wave outward that reaches Voyager about a year later. The wave causes the plasma surrounding the spacecraft to sing.”

Instruments on Voyager not only register these waves, but also measure quite precisely the oscillations of the surrounding plasma – allowing scientists to work out whether it’s currently in metaphorical deep water or still paddling in the shallows. The latest measurement - the third in a series of recent plasma waves - confirm that Voyager is a long way out.

Stone said: "The tsunami wave rings the plasma like a bell. While the plasma wave instrument lets us measure the frequency of this ringing, the cosmic ray instrument reveals what struck the bell - the shock wave from the sun."

Voyager 1's current location. The scale on this map is logarithimic - meaning that the distances marked are multipled as they get further out. Credit: Wikimedia commons.

However, despite these measurements Nasa are still hedging their bets somewhat, clarifying that although Voyager 1 has entered interstellar space it’s not yet exited the Solar System – a boundary usually defined by a hypothetical region of outer space known as the Oort cloud.

This is thought to be a spherical cloud of mostly icy debris, small objects that are pleasingly known as 'planetesimals'. If something's still a part of the Oort cloud then it's still in the gravitational grip of the Sun - meaning it's still, technically, a part of the Solar System.

And how long will it be since Voyager 1 gets through this part of space? Current predictions are 300 years to reach the edge of the Oort Cloud and then another 30,000 to exit it. Voyager 1 may have travelled further from Earth than any other man-made object in existence, but to quote sci-fi author Douglas Adams, “that’s just peanuts compared to space.”

PROMOTED VIDEO
Life and Style
ebookNow available in paperback
ebooks
ebookPart of The Independent’s new eBook series The Great Composers
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

ES Rentals

    iJobs Job Widget
    iJobs Gadgets & Tech

    Ashdown Group: Moodle Developer (PHP ,Linux, Apache, MySQL, Moodle)

    £35000 - £45000 per annum: Ashdown Group: Moodle Developer (PHP ,Linux, Apache...

    Recruitment Genius: Web Developer

    £17000 - £30000 per annum: Recruitment Genius: This is a fantastic opportunity...

    Recruitment Genius: Junior .NET Web Developer - Winform / MVC

    £21000 - £26000 per annum: Recruitment Genius: This Award-winning pharma softw...

    Recruitment Genius: Senior Java Developer

    £30000 - £45000 per annum: Recruitment Genius: A Senior Java Developer is requ...

    Day In a Page

    Isis in Iraq: Yazidi girls killing themselves to escape rape and imprisonment by militants

    'Jilan killed herself in the bathroom. She cut her wrists and hanged herself'

    Yazidi girls killing themselves to escape rape and imprisonment
    Ed Balls interview: 'If I think about the deficit when I'm playing the piano, it all goes wrong'

    Ed Balls interview

    'If I think about the deficit when I'm playing the piano, it all goes wrong'
    He's behind you, dude!

    US stars in UK panto

    From David Hasselhoff to Jerry Hall
    Grace Dent's Christmas Quiz: What are you – a festive curmudgeon or top of the tree?

    Grace Dent's Christmas Quiz

    What are you – a festive curmudgeon or top of the tree?
    Nasa planning to build cloud cities in airships above Venus

    Nasa planning to build cloud cities in airships above Venus

    Planet’s surface is inhospitable to humans but 30 miles above it is almost perfect
    Surrounded by high-rise flats is a little house filled with Lebanon’s history - clocks, rifles, frogmen’s uniforms and colonial helmets

    Clocks, rifles, swords, frogmen’s uniforms

    Surrounded by high-rise flats is a little house filled with Lebanon’s history
    Return to Gaza: Four months on, the wounds left by Israel's bombardment have not yet healed

    Four months after the bombardment, Gaza’s wounds are yet to heal

    Kim Sengupta is reunited with a man whose plight mirrors the suffering of the Palestinian people
    Gastric surgery: Is it really the answer to the UK's obesity epidemic?

    Is gastric surgery really the answer to the UK's obesity epidemic?

    Critics argue that it’s crazy to operate on healthy people just to stop them eating
    Homeless Veterans appeal: Christmas charity auction Part 2 - now LIVE

    Homeless Veterans appeal: Christmas charity auction

    Bid on original art, or trips of a lifetime to Africa or the 'Corrie' set, and help Homeless Veterans
    Pantomime rings the changes to welcome autistic theatre-goers

    Autism-friendly theatre

    Pantomime leads the pack in quest to welcome all
    The week Hollywood got scared and had to grow up a bit

    The week Hollywood got scared and had to grow up a bit

    Sony suffered a chorus of disapproval after it withdrew 'The Interview', but it's not too late for it to take a stand, says Joan Smith
    From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?

    Panto dames: before and after

    From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?
    Thirties murder mystery novel is surprise runaway Christmas hit

    Thirties murder mystery novel is surprise runaway Christmas hit

    Booksellers say readers are turning away from dark modern thrillers and back to the golden age of crime writing
    Anne-Marie Huby: 'Charities deserve the best,' says founder of JustGiving

    Anne-Marie Huby: 'Charities deserve the best'

    Ten million of us have used the JustGiving website to donate to good causes. Its co-founder says that being dynamic is as important as being kind
    The botanist who hunts for giant trees at Kew Gardens

    The man who hunts giants

    A Kew Gardens botanist has found 25 new large tree species - and he's sure there are more out there