The Solar System is surrounded by a vast bubble of plasma created by solar wind flowing outward from the Sun. This bubble shields the system from most of the cosmic radiation that passes through the interstellar medium. Meanwhile, as our system orbits the center of the Milky Way, it creates a rounded "nose" region ahead of it and a "tail" in its wake. Scientists are divided as to the shape of the heliosphere, with some arguing that it resembles a comet, while others favor a croissant-shaped profile.

The boundaries of the heliosphere are dynamic, the outer edge constantly shifting in response to changing solar conditions, expanding during solar maximum and contracting at solar minimum. Researchers at the Southwest Research Institute (SwRI) are busy studying the heliosphere so astronomers can create predictive models that will tell them the location of the termination shock - the heliosphere's outer boundary - in the direction the New Horizons probe is traveling.

Their findings were presented in two scientific papers that appeared in The Astrophysical Journal and the journal Advances in Space Research. The team, led by SwRI Post-Doctoral Researcher Dr. Jonathan Gasser, combined a solar wind forecasting method with analytical and numerical heliosphere models to determine where New Horizons will encounter the first plasma boundary in the outer heliosphere.