Probe at doorstep to interstellar space

2013-06-28 12:03
This artist's rendering shows the Voyager spacecraft which will bid adieu to the solar system and enter a new realm of space. (Nasa, AP)

This artist's rendering shows the Voyager spacecraft which will bid adieu to the solar system and enter a new realm of space. (Nasa, AP)

Multimedia   ·   User Galleries   ·   News in Pictures Send us your pictures  ·  Send us your stories

Cape Canaveral – Reports last summer that Nasa's long-lived Voyager 1 space probe had finally left the solar system turned out to be a bit premature, scientists said on Thursday.

Rather, the spacecraft, which was launched in 1977 for a five-year mission to study Jupiter and Saturn, has found itself in a previously unknown region between the outermost part of the solar system and interstellar space.

It is an unusual and unexpected thoroughfare, a place where charged particles from the sun have virtually disappeared and those coming from galactic cosmic rays beyond the solar system are plentiful.

By that measure alone, scientists initially thought Voyager 1 did indeed finally reach interstellar space on 25 August 2012, becoming the first man-made object to leave the solar system.

But one key measurement killed that theory. The magnetic field in which Voyager 1 travelled was still aligned like the sun's. If the probe were truly in interstellar space, scientists expect that the direction of the magnetic field would be different.

“You can never exclude a really peculiar coincidence, but this was very strong evidence that we're still in the heliosheath” – the bubble of plasma from the sun that surrounds the solar system, said Voyager scientist Leonard Burlaga, with Nasa's Goddard Space Flight Centre in Greenbelt, Maryland.

Additional measurements later turned up a second odd reading. The cosmic ray particles were not uniformly distributed around Voyager 1 like scientists expected them to be in interstellar space. Instead, the charged particles, which stem from distant supernova explosions, were oriented in particular directions.

That led scientists to conclude that Voyager 1 was in some sort of magnetic boundary zone, where particles from inside and outside the solar system could easily swap places, but where the sun's influence still reigns supreme.

“We have no explanation for why we even found this new region,” Burlaga told Reuters.

So far, Voyager's sister probe, Voyager 2, which is exiting the solar system in a different direction, has not encountered the same phenomena – nor may it ever.

“Voyager 2 has seen exactly what the models predicted we would see, unlike Voyager 1, which didn't,” said lead scientist Ed Stone, with the California Institute of Technology in Pasadena, California.

Voyager 1 may be in an unusual place where the heliosheath and interstellar space connect, he added.

Voyager 1 is now about 18 billion kilometres from Earth. At that distance, it takes radio signals, which move at the speed of light, 17 hours to make a one-way trip to Earth.

Scientists do not know how much farther Voyager has to travel to reach interstellar space. The spacecraft, which is powered by the slow decay of radioactive plutonium, will begin running out of energy for its science instruments in 2020. By 2025, it will be completely out of power.

The research appears in the journal Science this week.

Read more on:    nasa  |  space

Join the conversation! encourages commentary submitted via MyNews24. Contributions of 200 words or more will be considered for publication.

We reserve editorial discretion to decide what will be published.
Read our comments policy for guidelines on contributions.
NEXT ON NEWS24X publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.

Comment on this story
Comments have been closed for this article.

Inside News24


Millions of plastic particles in our food!

Scientists and researchers believe that almost five million tons of plastic is dumped in the oceans every year and it’s affecting our food.



Plastic on your plate
Prince George the green prince?
Lean, green, drifiting machine
One man's $1 million vision for an eco Africa

Book flights

Compare, Book, Fly

Traffic Alerts

The Leo moon adds an element of drama and entertainment. A significant person that you may consult or confide in may play more

There are new stories on the homepage. Click here to see them.


Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.

Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire network.


Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.

Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.