Have you ever been out at night and seen a streak of light blast across the sky and disappear? Ever wonder where that shooting star came from, or how it got to be in your sky?

A Yale-led team of astronomers has found a third galaxy devoid of dark matter—located alongside the other two in a formation that has never been seen before. Astronomers have followed a faint, cosmic trail of gas to a third galaxy that has no dark matter.

We think of atomic clocks as the definitive timekeepers. They are famous for being accurate down to the picosecond. Unfortunately, they are still subject to general relativity, so if you put them on a different planet, they will track time slightly faster or slower than on Earth, depending on the planet’s gravity. In Mars’ case, an atomic clock on its surface is sitting in a slightly shallower gravity well, meaning that time moves slightly faster there. Therefore, as we begin to expand our technological footprint on the red planet, we will need a way to standardize how time is measured there. Dr. Slava Turyshev, a researcher at NASA’s Jet Propulsion Laboratory, proposes just such a framework in a new paper available on the arXiv preprint server.

In rocky planets such as Earth and Mars, the oxidation state of the mantle is thought to strongly influence the melting temperature of mantle materials (i.e., magma generation), the composition of volcanic gases, and ultimately the evolution of surface environments. In particular, during the solidification of the “magma ocean,” which is believed to have been widespread during the early stages of planetary formation, the oxidation state in which iron is incorporated into minerals is considered crucial for understanding subsequent mantle evolution.

Scientists await a big splash in the Pacific Ocean as one of the most research-packed Dragon spacecraft to date returns, completing the 34th SpaceX commercial resupply mission to the International Space Station for NASA. Biological and materials samples, along with tested hardware, are heading back to research teams on Earth for further analysis, advancing NASA’s work to prepare humans for exploration beyond low Earth orbit and to deliver benefits back home.