Scientists call the realm of ​​space influenced by the sun the heliosphere – but without an interstellar probe they don’t know much about its shape

The sun warms the earth, making it habitable for humans and animals. But that's not all it does. It affects a much larger area of ​​space. The heliospherethe realm of ​​space influenced by the sun, is over 100 times larger than the gap from the sun to the earth.

The sun is a star that continually emits a gradual stream of plasma – high-energy ionized gas – called the solar wind. In addition to the constant solar windThe sun also occasionally emits plasma eruptions, which coronal mass ejectionsthat may contribute to Northern Lightsand bursts of sunshine and energy, so-called flares.

The plasma emanating from the sun expands through space along with the sun’s magnetic field. Together they form the heliosphere inside the encircling local interstellar medium – the plasma, neutral particles and dirt that fill the space between stars and their respective astrospheres. Heliophysicists like me want to know the heliosphere and its interaction with the interstellar medium.

The eight known planets of the solar system, the asteroid belt between Mars and Jupiter, and the Kuiper Belt – the band of celestial bodies beyond Neptune that features the planetoid Pluto – are all situated within the heliosphere. The heliosphere is so large that the objects within the Kuiper Belt orbit closer to the sun than to the the following frontier of the heliosphere.

A comparison of the distance an interstellar probe could reach beyond the boundary of the heliosphere compared to Voyager and New Horizons.
Artist's impression of the heliosphere and its position within the local interstellar medium and the Milky Way. An interstellar probe could reach further than any previous spacecraft and help scientists get a more in-depth take a look at our heliosphere – the Sun's influence in space – from the surface.

Heliospheric protection

When distant stars explode, they emit large amounts of radiation in the shape of high-energy particles into interstellar space. often known as cosmic radiationThis cosmic radiation will be dangerous to living beings and might damage electronic devices and spacecraft.

The Earth's atmosphere protects life on the planet from the results of cosmic radiation, but as well as, the heliosphere itself acts as a cosmic shield against most interstellar radiation.

In addition to cosmic radiation, neutral particles and dirt from the local interstellar medium also flow into the heliosphere. These particles can influence the space across the Earth and might even change how the solar wind reaches the earth.

Supernovas and the interstellar medium may additionally have had an influence the origin of life And the evolution of man on Earth. Some researchers predict that tens of millions of years ago the heliosphere got here into contact with a chilly, dense cloud of particles within the interstellar medium, which caused the heliosphere to shrinkthereby exposing the Earth to the local interstellar medium.

An unknown form

However, scientists have no idea the precise shape of the heliosphere. Models have different shapes from spherical to comet-like to croissant-shaped. These predictions vary Their size is 100 to a thousand times the gap between the sun and the earth.

However, scientists have defined the direction by which the Sun moves because the “nose direction” and the other way because the “tail direction.” The nose direction must have the shortest distance to the heliopause – the boundary between the heliosphere and the local interstellar medium.

A labeled diagram showing the heliosphere as part of a gray oval, with two small spacecraft just outside its boundaries.
Artist's impression of the heliosphere – true shape is unknown. Labels for the Sun, heliopause, and nose and tail directions have been added, as well for instance of the flank direction. The Voyager probes are believed to have crossed the heliosphere during their decades-long journey.

No probe has ever taken a great take a look at the heliosphere from the surface or properly sampled the local interstellar medium. This could tell scientists more in regards to the shape of the heliosphere and the way it interacts with the local interstellar medium, the space environment beyond the heliosphere.

Crossing the heliopause with Voyager

In 1977, NASA launched the Travel mission: Its two space probes flew past Jupiter, Saturn, Uranus and Neptune within the outer solar system. Scientists have determined that after observing these gas giants in 2012 and 2018 respectively, the probes individually crossed the heliopause and entered interstellar space.

Although Voyager 1 and a pair of are the one probes which have ever potentially crossed the heliopause, their planned mission durations have long since exceeded them and so they can not transmit the obligatory data because their instruments are slowly failing or shutting down.

These spacecraft were designed to check planets, not the interstellar medium, meaning they don't have the precise instruments to make all of the measurements of the interstellar medium or heliosphere that scientists need.

This is where a possible interstellar probe mission could are available. A probe designed to fly beyond the heliopause would help scientists understand the heliosphere by observing it from the surface.

An interstellar probe

Because the heliosphere is so large, It would take a long time for a probe to succeed in the border.even using gravity support from a large planet like Jupiter.

The Voyager spacecraft will not have the ability to supply data from interstellar space long before an interstellar probe leaves the heliosphere. And once the probe is launched, it would take about 50 years or more to succeed in the interstellar medium, depending on its trajectory. This implies that the longer NASA waits to launch a probe, the longer scientists may have to go without missions within the outer heliosphere or the local interstellar medium.

NASA is considering developing a interstellar probeThis probe would take measurements of the plasma and magnetic fields within the interstellar medium and image the heliosphere from the surface. In preparation, NASA asked greater than 1,000 scientists for input on a mission concept.

The first report advisable moving the probe on a trajectory that deviates about 45 degrees from the direction of the highest of the heliosphere. This trajectory would retrace a part of Voyager's route, reaching some recent regions of space. This would allow scientists to check recent regions and revisit some partially known regions of space.

This path would only give the probe a partial view of the heliosphere and it could not have the ability to see the heliotail, the region scientists know the least about.

In the heliotail, scientists predict that the plasma that makes up the heliosphere mixes with the plasma that makes up the interstellar medium. This happens through a process called magnetic reconnectionallowing charged particles from the local interstellar medium to flow into the heliosphere. Just just like the neutral particles that enter through the nose, these particles affect the space environment throughout the heliosphere.

In this case, nevertheless, the particles are charged and might interact with the magnetic fields of the Sun and the planets. Although these interactions happen on the boundaries of the heliosphere, very removed from the Earth, they influence the composition of the inside of the heliosphere.

In a recent study In Frontiers in Astronomy and Space Sciences, my colleagues and I examined six possible launch directions from tip to tail. We found that a trajectory that cuts the flank of the heliosphere toward the tail provides the perfect perspective on the form of the heliosphere, relatively than exiting near the tip.

A trajectory on this direction would give scientists a novel opportunity to check a completely recent area of ​​space throughout the heliosphere. As the probe leaves the heliosphere and enters interstellar space, it could get an outside-the-box view of the heliosphere from an angle that will give scientists a more accurate idea of ​​its shape – particularly within the controversial tail region.

No matter which direction an interstellar probe is launched in, the scientific knowledge it ultimately provides might be invaluable and, within the truest sense of the word, astronomical.

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