Phys.org has published the latest Mercury findings about a crater near its equator that appears to be bubbling. NASA scientists suggest that Mercury could be hollow inside, or at least partially so.
NASA’s Messenger Spacecraft captured the photo close up of the interior of the crater. They theorize that these types of craters, which have been observed in various other places on the planet are young and caused by, “Solar wind.” Jason Major of Phys.org writes:
A recent image acquired by NASA’s MESSENGER spacecraft shows the interior of Eminescu, a youngish 130-km (80 mile) wide crater just north of Mercury’s equator. Eminescu made science headlines last year with MESSENGER’s discovery of curious eroded blotches called “hollows” scattered across its interior and surrounding its central peak, and now it looks like the spacecraft may have spotted some of these strange features in their earliest stages of formation along the inner edge of the crater’s rim.
This is what NASA scientists believe causes these porous-looking craters, writes Major:
It’s thought that hollows are formed by the solar wind constantly blasting Mercury’s surface, scouring away deposits of volatile materials in its crust that have been left exposed by impacts.
Phys.org provides a definition for solar wind, partially sourced from Wikipedia.
The solar wind is a stream of charged particles—a plasma—ejected from the upper atmosphere of the sun. It consists mostly of electrons and protons with energies of about 1 keV. The stream of particles varies in temperature and speed with the passage of time. These particles are able to escape the sun’s gravity, in part because of the high temperature of the corona, but also because of high kinetic energy that particles gain through a process that is not well-understood.
The solar wind creates the Heliosphere, a vast bubble in the interstellar medium surrounding the solar system. Other phenomena include geomagnetic storms that can knock out power grids on Earth, the aurorae such as the Northern Lights, and the plasma tails of comets that always point away from the sun.