Our understanding of the first seconds of our Universe’s existence is little more than an informed guess, based on inference and extrapolation. “Yet these first moments are the key to many of our most urgent and enduring cosmic mysteries,” says cosmologist Dan Hooper at the University of Chicago told The Daily Galaxy. “Understanding this era,” he adds, “is essential to understanding our universe.”
“They’re out there,” goes the common quip about extraterrestrials. It would seem more likely to be true in light of a 2019 study by astrophysicists at the Georgia Institute of Technology who modeled the evolution of axial tilts of Earth-like analogs in different star systems, including binary stars. Earth’s axial tilt varies only slightly, an important ingredient for climate stability that favors the evolution of complex life. Of all their simulated Earth analogs with axial tilts similarly steady to Earth’s, the astrophysicists found that 87% of them were in binary star systems.
“We always thought of our Galaxy as an inactive galaxy, with a not so bright center,” said Magda Guglielmo from the University of Sydney about 2019 Hubble Space Telescope data showing that a titanic, expanding beam of energy sprang from close to the SgrA*, the supermassive black hole in the center of the Milky Way, 3.5 million years ago, shooting a cone-shaped burst of radiation through both poles of the Galaxy and beyond into deep space.
Although cosmic inflation is well known for resolving some important mysteries about the structure and evolution of the universe, other very different theories can also explain these mysteries. In some of these theories, the state of the universe preceding the Big Bang – the so-called primordial universe – was contracting instead of expanding, and the Big Bang was thus a part of a Big Bounce.
During a keynote speech at a NASA conference a decade ago on the search for extraterrestrial life an attendee shouted out: “We have no idea what’s out there!” One of NASA’s goals is to search for life on other planets like Mars, where there was once flowing water and a thick atmosphere, or moons of the outer solar system like Europa and Enceladus, where vast water oceans churn under thick layers of ice. But what if life on those worlds doesn’t use our DNA? How could we recognize it? A 2019 DNA breakthrough may be the key to answering these questions and many more.
Determining the age of a star can be one of the trickiest measurements an astronomer can make. Stars don’t obviate their age like humans do — with wrinkles around the eyes, grey hair, or brittle bones. Instead stars give hints at their age through things like their motion, rotation rate, chemistry, and placement in the Galaxy. Finding “extrema” on the age spectrum for stars — the oldest and youngest — is much easier than trying to find middle aged objects like our Sun. In this article, we reveal five fast facts about the youngest stars in the Galaxy.
“There are precious few fossil relics of the early Universe,” Brian Keating, Chancellor’s Distinguished Professor of Physics at UC San Diego, and author of Think Like a Nobel Prize Winner,” told The Daily Galaxy. “Just after the Big Bang,” Keating explained, “came the epoch of Big Bang nucleosynthesis, ending a few minutes later. The Cosmic Microwave Background, the universe’s oldest light, came about 380,000 years later. Then the great cosmic darkness began. That darkness had to end, or else we would not be here asking what caused the Universe to be so dim.