The only human spacecraft to enter galaxy were two Voyager spacecraft, which traveled for more than 30 years to get there. After Pluto’s orbit ends at the end of the Sun’s influence, the spacecraft enters orbit between stars known as galaxies. In that galaxy are the Big Bang and other particles from billions of stars in the universe. NASA’s New Horizons spacecraft has provided data used in a recently published study that looks at an important property of galaxy media, including how thick it is.
The Data shown The galaxy contains 40 percent more hydrogen atoms than some previous studies had expected. The results combine other measurements and give us a new idea of what galaxy space looks like. The magnetic field around the sun, called the heliosphere, protects our planet in the solar system from high levels of radiation and stellar gases that float around the high magnetic field.
The heliosphere can repel charged particles, but allows half of the local neutral gases to pass through because they contain a symmetrical number of protons and electrons. Scientists compare this to running through heavy fog and drawing water. When those galaxies enter the heliosphere, they are attacked by sunlight and solar wind particles. This causes the electrons to be lost and converted to positively charged “picking ions”.
Despite that change, the particles still represent how the galaxy is. NASA is clear that they do not have direct observations of galaxies from New Horizons, but can observe the ions they pick up. New Horizons has been working in space since 2006, and five years have passed since its encounter with Pluto, where it captured the first close-up images of the dwarf planet.
The spacecraft has an instrument called the solar wind around Pluto or the SWAP instrument to detect pickup ions and tell between them and normal solar air. The amount of pickup ions it detects indicates the thickness of the fog in the galaxy we pass through.