Something old, something new (4/20/23)

Good afternoon, and happy Starship test launch day to all who celebrate.

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Something New in the Universe

The universe is vast, and if the constant flush of new astronomical findings can tell us anything, it’s we have not yet seen all there is to see.

A team of researchers from Johns Hopkins University have come up with the potential for an entirely new kind of celestial body. They named the proposed object a “topological soliton,” which could bend space-time the same way as a black hole, but, instead of having an event horizon after which no light can escape, scatters weak rays of light back into space.

To be clear: Topological solitons are theoretical, and haven't been spotted by sensors on Earth. (At least, not yet.)

Searching the universe: In 2015, researchers at the LIGO (Laser Interferometer Gravitational-Wave Observatory) detected gravitational waves—ripples in space-time that move through space at the speed of light—for the first time. The finding added a notch to Einstein’s belt by reaffirming the theory of general relativity, and provided direct observational evidence for the existence of black holes.

The ability to directly measure gravitational waves has sparked a flurry of new black-hole-related science. It’s a whole lot easier to confirm a black hole’s existence and to suss out its qualities than it was just a decade ago. But if there are celestial objects out there that behave like black holes but aren’t, the research team says we may not be prepared to discern between the real black holes and other potential high-gravity objects.

“How would you tell when you don't have a black hole?” Ibrahima Bah, an author of the study, said in a press release. “We don't have a good way to test that.”

An alternative solution: Inspired by the power of the LIGO detector, the research team set out to find other reasonable possibilities for readings that look like confirmed black holes. They built a computational model of an object that produced identical gravitational wave readings to a black hole, but upon further inspection, looked different. 

“Light is strongly bent, but instead of being absorbed like it would in a black hole, it scatters in funky motions until at one point it comes back to you in a chaotic manner,” said Pierre Heidmann, a Johns Hopkins University physicist and lead author on the study. “You don’t see a dark spot. You see a lot of blur, which means light is orbiting like crazy around this weird object.”

Keep an eye out: Topological solitons aren’t the first theoretical, unseen objects scientists have proposed—gravastars and boson stars, for example, could also exist somewhere out there as high-gravity bodies. The team aims to continue refining its model, preparing astronomers to spot potential brand-new objects.

Other News from the Cosmos

• Distant galaxies from the early universe still behave in a way that is consistent with the theory of general relativity, a Kyoto University study confirmed.

• Metal-poor stars may be more likely to support life on orbiting planets through the spectrum of UV radiation they emit.

• An exoplanet has been identified using direct imaging and a new technique called precision astrometry, which uses a star’s motion through the sky to determine if it has planets in orbit.

• Astronomers measured the 3D shape of the M87 galaxy.

• JWST observations show ancient galaxies so large that they contradict the standard model of cosmology, which describes how the universe likely evolved after the Big Bang.

• RHESSI, a NASA solar energy imaging spacecraft, reentered the Earth’s atmosphere last night after 21 years in orbit.

The View from Space

Happy early 33rd birthday to Hubble! The famed space telescope launched on April 25, 1990. Today, it released this image of a nebula in the Perseus molecular cloud.