Skip to main content

Space probe sees solar system's tail

This illustration of the cross-section of the tail of the solar system shows slow solar wind in yellow and fast solar wind in red.
This illustration of the cross-section of the tail of the solar system shows slow solar wind in yellow and fast solar wind in red.
STORY HIGHLIGHTS
  • NASA's IBEX probe has new information about our solar system's tail
  • Interstellar magnetic fields influence the shape of the tail
  • The magnetic bubble around the solar system is called the heliosphere

(CNN) -- Thanks to solar wind blowing out from the sun in all directions at a million miles per hour, material from comets gets whipped back into a formation that looks like a tail.

Now, scientists know that our solar system has a tail of its own, with a surprising shape.

NASA researchers working with data from the Interstellar Boundary Explorer announced Wednesday they have for the first time mapped the solar system's tail, called the heliotail. Their study is published in the Astrophysical Journal.

By "tail," scientists don't mean a furry appendage hanging off Pluto, which is not classified as a planet anymore. Rather, the tail is a stream of solar wind plasma -- charged particles -- and magnetic field, trailing off behind the heliosphere.

The heliosphere is a magnetic bubble that surrounds our solar system, as well as the solar wind and our sun's magnetic field. This bubble doesn't stop at the planets -- it extends at least 8 billion miles beyond them.

These new observations help scientists better understand the structure surrounding our solar system.

"Scientists had always presumed that the heliosphere had a tail. We've seen it around other stars, we know the sun is moving relative to interstellar gas," said Eric Christian, IBEX mission scientist at NASA's Goddard Space Flight Center. "But this is actually the first real data that we have that gives us the shape of the tail."

If we could look at a cross-section of the solar system's tail, its shape would resemble a four-leaf clover. The "leaves" on the side are composed of slow-moving particles from lower energy solar wind, and the leaves on the top and bottom are fast-moving particles from high-speed solar wind.

On its "front," the heliosphere is more bullet-shaped, but it is asymmetrical because of the influence of magnetic fields from interstellar space, said David McComas, lead author on the paper and principal investigator for IBEX at Southwest Research Institute in San Antonio, Texas.

These magnetic fields from outside the solar system also affect the shape of the heliotail. McComas compares this to putting bungee cords around a beach ball and pulling on them. The force of the magnetic fields squeezes the tail so that its cross-section becomes flattered like an oval. The tail's cross-section also becomes twisted, and turns to align with the magnetic field.

Pressure from the interstellar gas and magnetic field causes the solar wind to bend back along the tail.

Researchers have not established the length of our solar system's tail, but they believe that it fades at the end and blends in with the rest of interstellar space.

Color filters help create this vivid image of Comet ISON, captured by NASA's Hubble Space Telescope on April 30. Color filters help create this vivid image of Comet ISON, captured by NASA's Hubble Space Telescope on April 30.
Up close with comets
HIDE CAPTION
<<
<
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
>
>>
Up close with comets Up close with comets

Astronomers had previously determined that other stars also have tails around their magnetic bubbles, which are called astrospheres. In order for such a sphere to form, there must be a balance of an inward compression of interstellar gas and a wind from the star that pushes outward.

The IBEX probe does not take photographs with light. Instead, it makes use of what are called energetic neutral atoms.

Most matter in the universe has an electric charge on it. But sometimes a charged particle, while moving fast through space, picks up an electron from neutral gas, which turns it into a neutral atom. Some of these neutral atoms are pointed back at Earth and are detected when they hit the IBEX spacecraft.

"Because they travel pretty much straight, you can trace them back to where they came from, and make a picture with these atoms instead of light," Christian said. "That's what IBEX does."

There are no space probes currently moving down the tail of our solar system, but the two Voyager spacecraft, which launched in 1977, are still floating further from Earth than any other terrestrial-made objects.

The Voyager and the IBEX missions are complementary, McComas said. The Voyager probes are akin to biopsies of the solar system, while IBEX is more like an MRI, understanding the big picture.

"While we have incredibly good and valuable information from those two locations where we have those spacecraft, how to put those into a global context and understand the really three-dimensional global interaction of the sun with the local part of the galaxy is really more a job for IBEX," McComas said.

According to the latest observations reported in the journal Science, Voyager 1 has traveled more than 11 billion miles from the sun. That brings it closer to reaching the distinction of being the first human-created object to reach interstellar space, which is loaded with material from other stars and a magnetic field from elsewhere in the Milky Way.

The two Voyager spacecraft are exploring a turbulent area called the heliosheath, as shown in this illustration.
The two Voyager spacecraft are exploring a turbulent area called the heliosheath, as shown in this illustration.

Scientists say Voyager 1 may take several more months, perhaps years, to fully escape the solar system.

Voyager 2 is still relatively closer to home, at 9 billion miles from the sun.

IBEX has enlightened scientists as to what the Voyager mission may find at the far reaches of our solar system and beyond, McComas said.

Without the interstellar probe, some say they wouldn't be able to make heads or tails of it.

Follow Elizabeth Landau on Twitter at @lizlandau and for more science news follow @CNNLightYears.

ADVERTISEMENT
Part of complete coverage on
Space
updated 12:10 PM EST, Fri December 5, 2014
An uncrewed test flight will send Orion 3,600 miles above Earth, farther into space than any craft designed for astronauts has gone since the last Apollo moon mission more than 40 years ago.
updated 9:02 AM EST, Mon December 1, 2014
The University of Colorado Boulder has announced a discovery 7,200 miles above Earth of a protective shield similar to the force fields you might see in "Star Trek."
updated 7:58 PM EST, Thu November 27, 2014
The International Space Station's 3-D printer will create objects that can be used by those living in the station.
updated 9:22 AM EST, Mon November 24, 2014
Shrimp crawling around rock chimneys spewing hot water deep in the Caribbean Sea may hold clues to the kinds of life that can thrive in extreme environments on other planets, NASA says.
updated 4:19 PM EST, Sat November 15, 2014
It's hard to top the tricky, first-ever landing on a comet but we'll try. Here are 11 other space missions to know about.
updated 6:21 PM EST, Fri November 7, 2014
Add another entry to the growing list of crazy footage captured by GoPro cameras.
updated 1:00 PM EDT, Sat November 1, 2014
It is in our DNA to explore the unknown. But pushing boundaries and exploring space is far from easy.
updated 11:42 AM EDT, Fri October 24, 2014
If there's one thing we've learned about the CNN iReport community, it's that you all love to capture celestial events.
updated 8:25 PM EDT, Sun October 12, 2014
Want to ride an elevator into space? A breakthrough in nanotechnology could mean we will be riding into space on a cable made of diamonds.
updated 1:52 PM EDT, Tue October 7, 2014
Astronauts lie motionless in a row of compartments with medical monitoring cables connected to their bodies, as their space ship cuts through the silent blackness.
updated 3:29 PM EDT, Sat September 20, 2014
This image from the Hubble Space Telescope indicates that a huge ring of dark matter likely exists surrounding the center of CL0024+17 that has no normal matter counterpart.
Scientists are closer to seeing a vast, invisible universe as a spectrometer in Earth orbit picks up possible clues of dark matter.
updated 9:21 AM EDT, Wed September 10, 2014
The Soviets sent stray dogs up to conquer space. This is what happened next
updated 5:20 AM EDT, Thu August 28, 2014
Scientists believe that a hot gas bubble was formed by multiple supernovas.
updated 11:47 AM EDT, Wed August 27, 2014
Robonaut is the next generation dexterous robot
Life aboard the International Space Station.
updated 9:53 PM EDT, Tue August 26, 2014
NASA's New Horizons mission hurtles toward Pluto in historic 3 billion mile expedition.
updated 11:56 PM EDT, Mon July 14, 2014
Scientists looking for signs of life in the universe -- as well as another planet like our own -- are a lot closer to their goal than people realize.
updated 11:51 AM EDT, Sun June 29, 2014
If you think you saw a flying saucer over Hawaii, you might not be crazy -- except what you saw didn't come from outer space, though that may be its ultimate destination.
updated 10:21 AM EDT, Fri June 13, 2014
When I first poked my head inside Virgin Galactic's newest spaceship, I felt a little like I was getting a front-row seat to space history.
updated 3:27 PM EST, Tue February 25, 2014
From a sheep ranch in Western Australia comes the oldest slice of Earth we know.
ADVERTISEMENT