Interstellar

2I/Borisov, detected in 2019 by amateur astronomer Gennady Borisov, is the first confirmed interstellar comet to pass through our solar system. Originating from an unknown star system, it gave astronomers a rare chance to analyze the chemical makeup of a body formed around another star, offering insights into how planets and comets may form elsewhere in the galaxy.

Kip Thorne's black hole Gargantua from the film Interstellar is being revisited, with explanations that it was not a mere visual effect but a scientifically grounded rendering where gravity dictates nearly everything on screen. Discussions cover what the shadow is, why the accretion disk appears above and below the hole, the role of the photon ring, and details the filmmakers deliberately left out.

Physicists have outlined how an extremely high-energy photon, carrying about 300 teraelectronvolts, could have travelled to Earth. Such photons are normally expected to be absorbed or degraded over cosmic distances, so explaining its arrival has implications for understanding extreme astrophysical sources and the limits of known particle physics.

Harvard astrophysicist Avi Loeb has published an essay arguing that the search for alien technology deserves an XPRIZE-style competition, offering a large cash reward to spur serious research into unidentified objects and potential extraterrestrial artefacts. Loeb, known for his controversial claims about the interstellar object 'Oumuamua and the Galileo Project, contends prize money would accelerate scientific efforts to detect signs of alien civilisations.

The Sharpless 155 complex, widely known as the Cave Nebula, is being discussed as a striking example of stellar nucleosynthesis and interstellar dynamics. The emission nebula sits roughly 2,400 light-years from Earth in the constellation Cepheus, where its distinctive structure marks regions of active star formation and the processing of elements inside young, massive stars.

A discussion is under way about which biological organisms would make the best candidates for humanity's first missions beyond the solar system, arguing that humans themselves are unlikely to be the first biological astronauts sent that far. The piece points to research on hardy life forms suited to long-duration interstellar conditions, prompting debate about what future deep-space exploration might actually look like.

NASA's Voyager 1, the most distant human-made object, is now 25.76 billion km (16.01 billion miles) from Earth and is on course to be a full light-day away in about 49 days, meaning a radio signal will take 24 hours to reach it. Its twin Voyager 2 sits at 21.55 billion km. Space enthusiasts are marking the milestone as a striking reminder of the scale of interstellar space.

Researchers have offered an explanation for how a photon with an energy of 300 teraelectronvolts, one of the highest-energy photons ever detected, could have travelled to Earth. Such extreme gamma rays are expected to be absorbed or degraded over interstellar distances, so the finding has drawn attention from physicists discussing the mechanisms that could allow it to survive the journey and what it reveals about cosmic accelerators.

NASA's Voyager 1, now 25.76 billion kilometres (16.01 billion miles) from Earth, is on track to become the first human-made object to sit one full light-day away, a milestone expected in roughly 49 days and 18 hours. Its twin, Voyager 2, trails at 21.55 billion kilometres. Space watchers are sharing live distance trackers as the anniversary of the mission's 1977 launch continues, marking the probe's steady march into interstellar space.

Astronomy enthusiasts are highlighting Messier 78, a reflection nebula in the constellation Orion. Unlike emission nebulae that glow from ionized gas, M78 consists of interstellar dust clouds reflecting the blue light of hot young stars embedded within it, making it a textbook example of its class. The object is being shared in science-focused discussions as a striking example of how dust rather than gas can light up deep-sky environments.