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.

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.

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.

Comet C/2023 A3 Tsuchinshan-ATLAS survived perihelion to become a fine dusk object for northern hemisphere observers.

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.

Sungrazer C/2024 S1 ATLAS breaks apart at perihelion.