Recurring slope lineae (RSL) on the red planet.
The enigmatic dark streaks on Mars — called recurring slope lineae (RSL) — that appear seasonally on steep, relatively warm Martian slopes are likely caused by salty liquid water, researchers said.
Study lead author Lujendra Ojha, of the Georgia Institute of Technology in Atlanta, told;
"The presence of liquid water on Mars' present-day surface therefore points to environment[s] that are more habitable than previously thought."
What will the announcement be about? Well, you’ll have to wait and see, as NASA won’t be releasing any more information to the public until then.