Earth's Neighborhood in Space Has 40 Percent More Hydrogen Atoms

Science Times
Science Times

Many are already starting to see what is beyond Earth with new observation missions. But NASA is still planning for future missions. Recently, the research found out that there is 40 percent more hydrogen in the Earth's neighboring region than we thought.

A research reported in the Astrophysical journal showed that in the region of space that covers our homeworld, the recent measurements produced by NASA's New Horizons mission observed 40 percent more hydrogen atoms. The new results will further shed light about what makes up our neighborhood.

It should be remembered that we are struck by cosmic objects when our planetary system passes across the Milky Way, but we are shielded by the heliosphere or the magnetic shield around the Earth. The heliosphere repels magnetic field-driven charged particles. Often recognized as providing a strong proton and electron equilibrium, more than half of the interstellar gasses that cover us are neutral.

In order to establish the density of neutral hydrogen at the termination shock or the area where the solar wind goes against the interstellar medium, Princeton University postdoctoral researcher and lead author of the analysis Pawel Swczyna used measurements from the Solar Wind Around Pluto or SWAP. In a space equal to a quarter of a gallon of milk, they detected 0.127 particles per cubic centimeter over a period of months, equivalent to 120 hydrogen atoms.

Interstellar Fog

Much like the Earth passes around the galaxy at rates exceeding 50,000 miles per hour, the whole solar system hurtles into the Milky Way. The galaxy is then protected by the gravitational bubble surrounding our Sun, known as the heliosphere, as planet cruise through a cloud of interstellar particles. Some interstellar gases, but not everything, circulate around the bubble.

Our heliosphere, driven by magnetic fields, repels charged particles. But more than half of the local interstellar gases are neutral, which implies that protons and electrons are balanced in size. The interstellar neutrals seep right in, contributing mass to the solar wind as we plow through them.

"It's like you're running through a heavy mist, picking up water," said Eric Christian, space physicist at NASA's Goddard Space Flight Center in Greenbelt, MD. "As you run, you're getting your clothes all soggy and it's slowing you down."

They are zapped by photons and slammed by solar wind waves shortly after some alien atoms drift through our heliosphere. In the chaos, many lose their electrons, becoming "pickup ions" positively charged. While altered, this latest population of particles brings with them mysteries of the fog outside.

Pawel Swaczyna, a postdoctoral researcher at Princeton University and lead author of the study, said the team hasn't seen interstellar atoms from New Horizons yet can detect these pickup ions. According to Swaczyna, these ions have been robbed of electrons. However, the scientists realize these particles came from beyond the heliosphere as neutral atoms.

The NASA New Horizons spacecraft, launched in January 2006, is the most fitting spacecraft for measuring purposes. Five years after its encounter with Pluto, where it captured the first close-up pictures of the dwarf planet, today it ventures across the Kuiper belt at the edge of our solar system, where the freshest pickup ions are. The Solar Wind Around Pluto or SWAP instrument of a spacecraft will identify these pickup ions, separating them from their far higher intensity than the usual solar wind.

The sum of pickup ions measured by New Horizons shows the fog's thickness through which we travel. The further pickup ions Fresh Horizons observes, the denser the cosmic cloud would be around, much like a jogger grows wetter going into a thicker fog.

Diverging Surprises

A 2001 analysis using Voyager 2 - some 4 billion miles away - determined how far the solar wind had slowed by the time it hit the spacecraft verified this outcome. A matching interstellar hydrogen density, around 120 hydrogen atoms in a quart-sized vacuum, was indicated by the slowdown, mostly due to intervening interstellar medium particles.

Newer research, however, converged around another figure. Scientists used data from NASA's Ulysses project calculated pickup ions from a distance much closer to the Sun than Jupiter and determined a density of around 85 atoms of hydrogen in a quarter of space. A similar outcome was found a few years later by a different analysis merging Ulysses and Voyager info.

But the latest amount started to look like the correct one after a little searching. For findings focused on faraway stars, the New Horizons calculations match well. On the other side, the Ulysses observations have a flaw: they were produced far closer to the Sun, where pickup ions are rarer and measurements are more unpredictable.

Swaczyna found that one of the equation numbers was obsolete. The results are 35 percent smaller than the current consensus value concerning the cumulative Ulysses / Voyager data. Recalculating them with the generally agreed value offered them an estimated fit with the calculations of New Horizons and the analysis of 2001.

Arik Posner, the author of the 2001 report at NASA Headquarters in Washington, D.C., said, the study is the proof of the universe's vintage, almost unknown finding comes as a surprise."

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