Scientists used NASA’s Voyager 2 to study the outer planets of the Solar System. They handed the first readings from interstellar space, which was collected after traveling more than 11 billion miles in more than 40 years. NASA’s Voyager 2 is the second probe to sail beyond the heliosphere – a vast area of magnetic fields and plasma generated by the Sun. Last year, it finally broke away from the solar system, entered the interstellar space, and joined its twin, Voyager 1, which was exited in 2012. The transmitted data was analyzed by a large group of physicists whose findings were published in five papers on Monday’s Nature Astronomy. Specifically, the study evaluated Voyager 2’s measurements of magnetic fields, cosmic rays, plasma and particle density inside and outside the heliosphere.
Many findings confirmed that Voyager 1 left the tiny backyard in the universe, which is useful in itself. One of the paper’s lead authors, Ed Stone, a project scientist for the Voyager mission, said that the probes of Voyager show us how the Sun interacts with stuff filling most of the space between the stars in Milky Way galaxy. He added that without the new data from Voyager 2, we would not be able to know about what we were observing with Voyager 1 was specific just to the location and time it passes through or characteristic of the entire heliosphere. The entire heliosphere is a giant protective bubble which shields the Solar System from the cosmic rays of the galaxy. It is made of plasma, commonly referred to as the solar wind, which flows throughout the system and cannot propagate further due to pressure in the interstellar medium. The edge of the bubble is called heliopause and the small area between both regions is called the heliosheath.
Voyager 2 found that the plasma temperature in the surrounding interstellar medium was lower than that in the heliosphere. Also, the plasma density is higher compared to the internal heliosphere, confirmed by measurements. The mystery remained is the magnetic field direction on both sides of the heliopause. They seem to be parallel, or in other words aligned, but no one knows why. This alignment was recorded by Voyager 1 and is now confirmed by Voyager 2. Voyager 1 has traveled more than 13.6 billion miles from the Sun, while Voyager 2 is 11.3 billion miles away. Both probes will continue to accelerate into the depths of the Milky Way galaxy indefinitely.