Earth is the sixth planet at the edge of our solar system. This means that we are not too far from this inhospitable frontier. We have sent various spacecraft out over the years so we know what the edge looks like.Yes, it is possible. However, it is still in development. The latest development, a 3D map showing the edge of the solar system that took 13 years, revealed some more details about this boundary, known as the outer heliosphere.The outer heliosphere is the area where the solar wind (or the stream of charged particles from the sun) is "deflected" and "draped back" by interstellar radiation. This was the location that Dan Reisenfeld, a space scientist at Los Alamos National Laborator in New Mexico, and the head of the team that carried out the research for the 3D map. The boundary formed by interstellar and solar wind at the outer reaches of our solar system is called the "outer heliosphere".Related: What happens to intergalactic space and time?NASA claims that Earthlings saw the outer edge of the solar system for the first time in 2012. Voyager I was a NASA spacecraft launched in 1977 and crossed into interstellar orbit in 2012. Voyager 2 followed suit, completing the feat in 2018. Voyagers 1 & 2 were equipped with golden records containing humpback whale songs, Louis Armstrong, and Bach. They also had scientific instruments. Voyagers 1 & 2 reported a drop in solar particles, and an increase in galactic radiation after they left the solar system. This was according to NASA's Jet Propulsion Laboratory, California Institute of Technology.The 3D map shows more details about the heliosphere. The inner layer that houses the sun and its planets is approximately spherical. It is believed to extend around 90 astronomical units in all directions. One AU is approximately the distance between Earth's surface and the sun. It is about 93 million miles or 150 million km. The outer layer is less symmetrical. The outer heliosphere is much less symmetrical in one direction. This is where the ever-moving sun moves through space, encountering cosmic radiation. It extends approximately 110 AU. However, Reisenfeld claims that it extends at least 350 AU in the other direction.The outer heliosphere is the area of space in which the solar wind (or the stream of charged particles emitted by the sun) is "deflected" and "draped back" by interstellar radio. (Image credit: NASA/JPL-Caltech)This lack of symmetry is caused by the sun's motion through the Milky Way. It encounters friction with the galactic radiation in front and creates a vacuum. Reisenfeld explained to Live Science that there is a lot plasma in the interstellar media, and that the inner heliosphere which is quite round is an obstacle in the stream of plasma flowing past it. It has the same effect of water flowing around rocks in a stream. There is a rush of water hitting the rock in front, and then a calm behind.The measurements for the 3D map were taken using the Interstellar Boundary Explorer, (IBEX), which was launched 2008 and is "the same size as a bus tire." NASA says it did so because the IBEX was "the size of an average bus tire". Reisenfeld explained that it is pronounced "like an animal" and refers to the ibex mountain gos who are known for their gravity-defying climbs up alpine hills. The bat is what IBEX most closely resembles.Bats use a pulse of sound to hunt insects such as mosquitoes. They then use the echo's time delay to determine the distance to their prey. IBEX also detects solar-wind particles which bounce back from the solar system's edges. This allows Reisenfeld and his associates to measure the length of their round trip, as well as the distances involved. Reisenfeld explained that the sun sends out a pulse, then we wait passively for a return signal form the outer Heliosphere. We use that time delay in order to determine the location of the outer Heliosphere.The protective bubble formed by the solar wind protects the Milky Way's outer rim from cosmic radiation. Reisenfeld stated that this is good news for us because "that radiation could damage spacecraft and can pose a risk to astronauts' health."But, these boundaries might not be so in the long-term. Reisenfeld pointed out that there is a correlation between strength of the sun's solar wind and number of spots. Sunspots are a temporary darkening of the sun's surface caused by intense magnetic disturbances. The Maunder minimum is a time period when there were few sunspots and therefore, weak solar winds. It was 1645-1715.Reisenfeld stated that the sunspots had disappeared for nearly a century and that if that happens, then the shape of our heliosphere could also have changed significantly. "We do observe variations in solar activity and at any moment, another Maunder minim could occur. It is not an unreasonable concern to worry that [heliospheres] shielding effectiveness could decrease over time.NASA will launch a new mission, the Interstellar Mapping and Acceration Probe (IMAP), in 2025 to learn more about the heliosphere. If everything goes according to plan IMAP will provide further information about the interactions between solar wind and cosmic radiation at our solar system's edge.Original publication on Live Science
