Michigan, The sun warms the Earth, making it habitable for people and animals. But that's not all, and it affects a much larger area of space.
The heliosphere, the region of space influenced by the Sun, is more than a hundred times larger than Earth's distance from the Sun.
The Sun is a star that constantly emits a steady stream of plasma – highly energetic ionized gas – called the solar wind. In addition to the constant solar wind, the Sun also occasionally releases bursts of plasma, called coronal mass ejections which can contribute to auroras, and explosions of light and energy, called flares.The plasma emitted from the Sun expands into space along with the Sun's magnetic field. Together they form the heliosphere within the surrounding local interstellar medium – the plasma, neutral particles and dust that fill the space between the stars and their respective astrospheres.
Heliophysicists like me want to understand the heliosphere and how it interacts with the interstellar medium. The eight known planets in the Solar System, the asteroid belt between Mars and Jupiter, and the Kuiper Belt – the band of celestial bodies beyond Neptune that includes the planet Pluto Have - all live within the heliosphere.
The heliosphere is so large that objects in the Kuiper Belt orbit much closer to the Sun than the closest extent of the heliosphere.Heliosphere ProtectionAs distant stars explode, they emit large amounts of radiation into interstellar space in the form of highly energetic particles known as cosmic rays. These cosmic rays can be dangerous to living organisms and can damage electronic equipment and spacecraft.
Earth's atmosphere protects life on the planet from the effects of cosmic radiation, but, even before that, the heliosphere itself acts as a cosmic shield from most interstellar radiation.
In addition to cosmic radiation, neutral particles and dust continuously flow into the heliosphere from the local interstellar medium. These particles can affect the space around Earth and even change the way the solar wind reaches Earth.Supernovae and the interstellar medium may also have influenced the origin of life on Earth and the evolution of humans.
Some researchers estimate that millions of years ago, the heliosphere came into contact with a cold, dense particle cloud in the interstellar medium, causing the heliosphere to contract, bringing the Earth into contact with the local interstellar medium.
An Unknown ShapeBut scientists don't really know what the shape of the heliosphere is. The shapes of the models range from spherical to comet-like and croissant-shaped. The size of these projections varies from hundreds to thousands of times the Earth's distance from the Sun.However, scientists have defined the direction of the Sun's rotation as the "nose" direction and the opposite direction as the "tail" direction. The direction of the nose should be the shortest distance from the heliopause – the boundary between the heliosphere and the local interstellar medium.
No probe has ever taken a good look at the heliosphere from outside or properly sampled the local interstellar medium. Doing so can tell scientists more about the shape of the heliosphere and its interactions with the space environment beyond the local interstellar medium, the heliosphere. Crossing the Heliopause with Voyager
In 1977, NASA launched the Voyager mission: its two spacecraft flew past Jupiter, Saturn, Uranus, and Neptune in the outer Solar System.Scientists determined that after seeing these gas giants, the probes crossed the heliopause and interstellar space separately in 2012 and 2018, respectively.
While Voyager 1 and 2 are the only probes to have potentially crossed the heliopause, they are well beyond their intended mission lifetime. They can no longer return needed data as their instruments gradually fail or lose power. These spacecraft were designed to study planets, not the interstellar medium. This means they don't have the right instruments to take all the measurements of the interstellar medium or heliosphere that scientists need.This is where a potential interstellar probe mission could come in. A probe designed to fly beyond the heliopause will help scientists understand the heliosphere by looking from the outside.
An Interstellar Probe Because the heliosphere is so large, it would take decades for a probe to reach the limit, even using gravitational assistance from a giant planet like Jupiter.
The Voyager spacecraft will no longer be able to provide data from interstellar space before the interstellar probe exits the heliosphere.
And once the probe is launched, depending on the trajectory, it will take about 50 or more years to reach the interstellar medium.This means that the longer NASA waits to launch a probe, the more scientists will be left with no missions to work on in the outer heliosphere or the local interstellar medium. NASA is considering developing an interstellar probe. The probe will measure plasma and magnetic fields in the interstellar medium and image the heliosphere from the outside. To prepare, NASA solicited input from more than 1,000 scientists on a mission concept.
Initial reports recommended the probe travel on a trajectory that is approximately 45 degrees off the nose direction of the heliosphere.This trajectory will follow part of Voyager's path, reaching some new regions of space. This way, scientists can study new areas and revisit some partially known regions of space.
This path will give the probe only a partially angled view of the heliosphere, and it will not be able to see the heliotail, about which scientists in the region know the least. In the heliotail, scientists estimate that the plasma that forms the heliosphere. Combines with what forms the interstellar medium. This occurs through a process called magnetic reconnection, which allows charged particles to flow from the local interstellar medium into the heliosphere.Like neutral particles entering through the nose, these particles affect the space environment within the heliosphere.
However, in this case, the particles have a charge and can interact with the solar and planetary magnetic fields. While these interactions occur at the boundaries of the heliosphere, far away from Earth, they affect the structure of the interior of the heliosphere.
In a new study published in Frontiers in Astronomy and Space Sciences, I and my colleagues evaluated six possible launch directions from nose to tail. We found that rather than exiting close to the nose direction, the tail projected to the side of the heliosphere. A trajectory cutting towards the direction will give the best perspective on the shape of the heliosphere.A trajectory in this direction would provide scientists with a unique opportunity to study an entirely new region of space within the heliosphere. When the probe exits the heliosphere into interstellar space, it will get a view of the heliosphere from the outside at an angle that will give scientists a more detailed idea of its shape – especially in the disputed tail region.
Ultimately, whichever direction the interstellar probe launches, the science it returns will be invaluable and literally astronomical.(talk) GRSGRS
The heliosphere, the region of space influenced by the Sun, is more than a hundred times larger than Earth's distance from the Sun.
The Sun is a star that constantly emits a steady stream of plasma – highly energetic ionized gas – called the solar wind. In addition to the constant solar wind, the Sun also occasionally releases bursts of plasma, called coronal mass ejections which can contribute to auroras, and explosions of light and energy, called flares.The plasma emitted from the Sun expands into space along with the Sun's magnetic field. Together they form the heliosphere within the surrounding local interstellar medium – the plasma, neutral particles and dust that fill the space between the stars and their respective astrospheres.
Heliophysicists like me want to understand the heliosphere and how it interacts with the interstellar medium. The eight known planets in the Solar System, the asteroid belt between Mars and Jupiter, and the Kuiper Belt – the band of celestial bodies beyond Neptune that includes the planet Pluto Have - all live within the heliosphere.
The heliosphere is so large that objects in the Kuiper Belt orbit much closer to the Sun than the closest extent of the heliosphere.Heliosphere ProtectionAs distant stars explode, they emit large amounts of radiation into interstellar space in the form of highly energetic particles known as cosmic rays. These cosmic rays can be dangerous to living organisms and can damage electronic equipment and spacecraft.
Earth's atmosphere protects life on the planet from the effects of cosmic radiation, but, even before that, the heliosphere itself acts as a cosmic shield from most interstellar radiation.
In addition to cosmic radiation, neutral particles and dust continuously flow into the heliosphere from the local interstellar medium. These particles can affect the space around Earth and even change the way the solar wind reaches Earth.Supernovae and the interstellar medium may also have influenced the origin of life on Earth and the evolution of humans.
Some researchers estimate that millions of years ago, the heliosphere came into contact with a cold, dense particle cloud in the interstellar medium, causing the heliosphere to contract, bringing the Earth into contact with the local interstellar medium.
An Unknown ShapeBut scientists don't really know what the shape of the heliosphere is. The shapes of the models range from spherical to comet-like and croissant-shaped. The size of these projections varies from hundreds to thousands of times the Earth's distance from the Sun.However, scientists have defined the direction of the Sun's rotation as the "nose" direction and the opposite direction as the "tail" direction. The direction of the nose should be the shortest distance from the heliopause – the boundary between the heliosphere and the local interstellar medium.
No probe has ever taken a good look at the heliosphere from outside or properly sampled the local interstellar medium. Doing so can tell scientists more about the shape of the heliosphere and its interactions with the space environment beyond the local interstellar medium, the heliosphere. Crossing the Heliopause with Voyager
In 1977, NASA launched the Voyager mission: its two spacecraft flew past Jupiter, Saturn, Uranus, and Neptune in the outer Solar System.Scientists determined that after seeing these gas giants, the probes crossed the heliopause and interstellar space separately in 2012 and 2018, respectively.
While Voyager 1 and 2 are the only probes to have potentially crossed the heliopause, they are well beyond their intended mission lifetime. They can no longer return needed data as their instruments gradually fail or lose power. These spacecraft were designed to study planets, not the interstellar medium. This means they don't have the right instruments to take all the measurements of the interstellar medium or heliosphere that scientists need.This is where a potential interstellar probe mission could come in. A probe designed to fly beyond the heliopause will help scientists understand the heliosphere by looking from the outside.
An Interstellar Probe Because the heliosphere is so large, it would take decades for a probe to reach the limit, even using gravitational assistance from a giant planet like Jupiter.
The Voyager spacecraft will no longer be able to provide data from interstellar space before the interstellar probe exits the heliosphere.
And once the probe is launched, depending on the trajectory, it will take about 50 or more years to reach the interstellar medium.This means that the longer NASA waits to launch a probe, the more scientists will be left with no missions to work on in the outer heliosphere or the local interstellar medium. NASA is considering developing an interstellar probe. The probe will measure plasma and magnetic fields in the interstellar medium and image the heliosphere from the outside. To prepare, NASA solicited input from more than 1,000 scientists on a mission concept.
Initial reports recommended the probe travel on a trajectory that is approximately 45 degrees off the nose direction of the heliosphere.This trajectory will follow part of Voyager's path, reaching some new regions of space. This way, scientists can study new areas and revisit some partially known regions of space.
This path will give the probe only a partially angled view of the heliosphere, and it will not be able to see the heliotail, about which scientists in the region know the least. In the heliotail, scientists estimate that the plasma that forms the heliosphere. Combines with what forms the interstellar medium. This occurs through a process called magnetic reconnection, which allows charged particles to flow from the local interstellar medium into the heliosphere.Like neutral particles entering through the nose, these particles affect the space environment within the heliosphere.
However, in this case, the particles have a charge and can interact with the solar and planetary magnetic fields. While these interactions occur at the boundaries of the heliosphere, far away from Earth, they affect the structure of the interior of the heliosphere.
In a new study published in Frontiers in Astronomy and Space Sciences, I and my colleagues evaluated six possible launch directions from nose to tail. We found that rather than exiting close to the nose direction, the tail projected to the side of the heliosphere. A trajectory cutting towards the direction will give the best perspective on the shape of the heliosphere.A trajectory in this direction would provide scientists with a unique opportunity to study an entirely new region of space within the heliosphere. When the probe exits the heliosphere into interstellar space, it will get a view of the heliosphere from the outside at an angle that will give scientists a more detailed idea of its shape – especially in the disputed tail region.
Ultimately, whichever direction the interstellar probe launches, the science it returns will be invaluable and literally astronomical.(talk) GRSGRS
