Brian Koberlein

Astronomers have detected ultra-high-energy gamma rays coming from the center of the Milky Way, with nearly 100 events of more than 100 teraelectron volts of energy. Researchers aren't sure what's generating so many of these extreme events, but it's where the Milky Way's supermassive black hole, which is surrounded by neutron stars and white dwarfs that strip material from nearby stars, is located. And all of this is surrounded by dense gas reaching millions of degrees.

The odds are good that we are not alone in the Universe. We have found thousands of exoplanets so far, and there are likely billions of potentially habitable planets in our galaxy alone. But finding evidence of extraterrestrial life is challenging, and even the most powerful telescopes we currently have may not produce definitive proof. But there are telescopes in the pipeline that may uncover life. It will be decades before they are built and launched, but when they are, which systems should they target first? That’s the question answered in a recent paper.

The TRAPPIST-1 system is exciting because of several Earth-sized worlds within the habitable zone of a red dwarf star, but it's also a dangerous environment, with powerful superflares sweeping past the planets. How would the hardiest Earth life handle that kind of environment? Researchers exposed two types of hardy Earth bacteria to TRAPPIST-1 level flares and found that both could handle it, even without any protective shielding. Life is surprisingly durable.

In 2005 astronomers found a pulsar rotating at 716 times a second. Now a team studying an X-ray binary has found another neutron star spinning at that rate.

Long-period comets can have orbits that can take hundreds of years before they return to the inner Solar System and sometimes come dangerously close to Earth. To search for potentially hazardous comets, astronomers have used meteor showers as a historical record. When the Earth passes through a meteoroid stream left by a comet, we see a meteor shower. From these showers, they can calculate the orbit of the comet and predict when it will come back to our neighborhood.

Dust grains older than the Sun can tell us about how supernovae enriched the cosmos with heavy elements, but the details are subtle and require more study.

Freeman Dyson proposed that advanced civilizations might eventually harvest all the energy coming from their stars by surrounding them with a swarm of solar-collecting satellites. But other astronomers have proposed that we might see all that rock go into the construction of artificial planets instead, surrounding a star with dozens of habitable worlds and captured rogue planets. If we detect a star system with a surprising number of planets, they could be artificial.

The spectra of distant galaxies shows that dying sun-like stars, not supernovae, enrich galaxies the most.

As we saw with JWST, it's difficult and expensive to launch large telescope apertures, relying on origami techniques to unfold the full mirror. A new paper proposes that telescope mirrors could be made out of a thin polymer that's only 200 micrometers thick. It could be rolled up inside a rocket fairing and then unrolled once it gets to space. This could allow apertures vastly larger than anything currently in space, with several working together as an interferometer.

The gravitational field of a rotating black hole is powerful and strange. It is so powerful that it warps space and time back upon itself, and it is so strange that even simple concepts such as motion and rotation are turned on their heads. Understanding how these concepts play out is challenging, but they help astronomers understand how black holes generate such tremendous energy. Take, for example, the concept of frame dragging.