Space News & Blog Articles

According to the leading theory of how the Earth-Moon system formed (the Giant Impact Hypothesis), a Mars-sized object (named Theia) collided with a proto-Earth 4.5 billion years ago. This turned both objects into molten lava, which eventually coalesced and cooled to form the Earth and Moon. Over time, the Moon migrated outward, eventually reaching its current, tidally locked orbit around Earth, where one side is permanently facing us. For decades, scientists have debated where Theia may have originated, whether it formed in the inner or outer Solar System.

The surface of the Earth is finite. We can measure it. If it was expanding, then its size would grow with time. And once again, good ol’ Earth helps us understand what the universe might be doing beyond our observable horizon.

Material science plays a critical role in space exploration. So many of the challenges facing both crewed and non-crewed missions come down to factors like weight, thermal and radiation tolerance, and overall material stability. The results of a new study from Young-Kyeong Kim of the Korea Institute of Science and Technology and their colleagues should therefore be exciting for those material scientists who focus on radiation protection. After decades of trying, the authors were able to create a fully complete “sheet” of Boron Nitride Nanotubes (BNNTs).

The Milky Way contains more than 100 billion stars, each following its own evolutionary path through birth, life, and sometimes violent death. For decades, astrophysicists have dreamed of creating a complete simulation of our Galaxy, a digital twin that could test theories about how galaxies form and evolve. That dream has always crashed against an impossible computational wall.

It is a scientific consensus that water once flowed on Mars, that it had a denser atmosphere, meaning that it was once habitable. Unfortunately, roughly 4.2 to 3.7 billion years ago, Mars' rivers, lake, and global ocean began to disappear as solar wind slowly stripped its atmosphere away. For scientists, the question of how long it remained habitable has been the subject of ongoing inquiry. Whereas some scientists maintain that Mars ceased being habitable billions of years ago, recent research suggests that it experienced periods of habitability that lasted for eons.

An expanding universe complicates this picture just a little bit, because the universe absolutely refuses to be straightforward. Objects are still emitting light, and that light takes time to travel from them over to here, but in that intervening time the universe grows larger, with the average distance between galaxies getting bigger (yes, I know that sometimes galaxies can collide, but we’re talking on average, at big scales here).

I honestly don’t have a decent analogy for you to explain how the universe is expanding without a center and without an edge. It just does, whether we can wrap our minds around it or not. But I CAN give you a way to think about it.