The heliosphere is shaped a bit like a comet, having a tail of about 350 astronomical units.
REPUBLIKA.CO.ID, JAKARTA — Scientists released the first 3D map of the heliosphere. The heiosphere is the final boundary between the solar system and interstellar space.
So far, it is known that the sun is very large, so the spacecraft Voyager 1 from the American Space Agency (NAS) is the farthest man-made object and has been floating for more than 40 years, but has not escaped the influence of the sun.
Voyager 1 is about 14 billion miles (22.5 billion kilometers) from the Sun, about four times the average distance from the sun to Pluto. Although most of the solar system appears to be empty space, it is actually inhabited by the solar wind and other electromagnetic radiation.
The sphere of influence of the sun is divided into a number of major regions, one of which is the heliosphere. These are bubble-like regions of the solar system, which form like long windsocks as they move with the sun through interstellar space. The heliosphere is filled with the sun’s magnetic field, protons, and electrons from the solar wind (charged particles emanating from the sun).
Reported Mixture, now for the first time astronomers have mapped heliosphere in three dimensions. The analysis confirmed suspicions from the theoretical model, that the heliosphere was shaped a bit like a comet, having a tail of about 350 astronomical units. Please note, one astronomical unit has a distance of about the Earth to the Sun.
The outer boundary of the heliosphere is known as the heliopause. This is where the pressure from the solar wind, which is greatly weakened so far from the sun, is canceled out by the pressure of interstellar space.
Researchers at Los Alamos National Laboratory used data from the Earth-orbiting Interstellar Boundary Explorer (IBEX) satellite, measuring charged particles ejected from the outermost region of the heliosphere to map the region in unprecedented detail. In the process, the three-dimensional map allows scientists to gain a better understanding of how the solar and interstellar winds interact.
“Model physics have been theorizing this boundary for years. But this is the first time we’ve actually been able to measure it and create a three-dimensional map of it,” said Dan Reisenfeld, a scientist at Los Alamos National Laboratory and lead author of the study, which was published in Astrophysical Journal.
Reisenfeld used a technique similar to how bats use sonar to detect their surroundings. Instead of detecting reflected acoustic waves, astronomers measure energetic neutral atoms (ENAs) or particles resulting from collisions between the solar and interstellar winds to create a map of the heliosphere.
As the ENA count rises, this could mean that the limit is near. Reisenfeld says the solar wind signals sent by the sun vary in strength, forming unique patterns.
“IBEX will see the same pattern in the ENA signal returning, two to six years later, depending on the energy of the ENA and the direction IBEX sees through the heliosphere. This time difference is how we find the distance to the ENA source region in a given direction,” explains Reisenfeld.
Reisenfeld said by doing so, scientists could see the boundaries of the heliosphere in the same way that bats use sonar to ‘see’ cave walls. Previously, simulations that calculated numbers from galactic cosmic ray measurements (ENA’s indirect indicator), concluded that the solar system’s heliosphere was shaped like a croissant rather than a comet.
However, this newly published 3-D map shows that the solar wind bubble is comet-like, although there is still uncertainty about the true shape of the heliosphere due to the inherent limits of the IBEX range. The heliosphere may indeed have a more bizarre shape and defining it is actually important from a practical point of view.
The heliosphere blocks 75 percent of the galaxy’s cosmic rays, which can damage spacecraft and the DNA of traveling astronauts.
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