Original reports, explanations and news from their publishers.
Rosetta reached comet 67P/Churyumov–Gerasimenko in August 2014 and stayed as it approached the Sun and moved away again. That long encounter let scientists connect a changing surface with the dust and gases escaping from it.
3 min read
ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0 · CC BY-SA 3.0 IGO
Pan-STARRS1 discovered ʻOumuamua on 19 October 2017, after it had already passed the Sun. Telescopes saw only an unresolved point of light. Tracking that point nevertheless established something decisive: it had arrived from beyond the Solar System and would leave again.
3 min read
ESO/K. Meech et al.
Gennady Borisov discovered the object now called 2I/Borisov on 30 August 2019. Unlike ʻOumuamua, it displayed a dusty coma. Its trajectory established an interstellar journey, while the escaping gas allowed astronomers to investigate material formed around another star.
3 min read
NASA, ESA and D. Jewitt (UCLA)
The ATLAS survey reported 3I/ATLAS on 1 July 2025. Its unbound trajectory identified an interstellar visitor, while its active coma gave telescopes access to gas and ice grains. Observations extending into 2026 turned that brief passage into a comparison with the ingredients of our own Solar System.
3 min read
NASA, ESA, David Jewitt (UCLA); Image Processing: Joseph DePasquale (STScI)
ESA’s Gaia mission repeatedly measured stars across the sky from 2014 to 2025. Those observations address a problem no external photograph can solve for us: the Solar System sits inside the Milky Way’s dusty disk, so its structure must be reconstructed from within.
3 min read
NASA/JPL-Caltech · illustration
A Hubble panorama released in January 2025 resolves roughly 200 million stars across Andromeda. By comparing their colours, brightnesses and locations, astronomers can investigate how our nearest large galactic neighbour assembled its disk.
3 min read
NASA, ESA, Benjamin F. Williams (UWashington), Zhuo Chen (UWashington), L. Clifton Johnson (Northwestern); Image Processing: Joseph DePasquale (STScI)
Hubble’s mosaic of Triangulum resolves nearly 25 million stars. Within the same galaxy, Webb’s 2024 images of NGC 604 show massive young stars excavating cavities in their birth cloud. Together the observations connect a galaxy-wide pattern with the physics inside one nursery.
3 min read
NASA, ESA, M. Durbin, J. Dalcanton and B. F. Williams (University of Washington)
Hubble’s view of the Whirlpool Galaxy shows blue star clusters and pink star-forming regions along two prominent arms. The nearby companion NGC 5195 adds a gravitational disturbance. The arms are a changing pattern in a rotating galaxy, not rigid strips of material.
3 min read
NASA, ESA, S. Beckwith (STScI) and the Hubble Heritage Team (STScI/AURA)
On 10 April 2019, the Event Horizon Telescope collaboration released an image of a bright ring surrounding a dark centre in M87. The observations measured radiation from hot material near a supermassive black hole, where gravity strongly changes the paths of light.
3 min read
NASA, ESA and the Hubble Heritage Team (STScI/AURA); Acknowledgment: P. Côté (Herzberg Institute of Astrophysics) and E. Baltz (Stanford University)
Hubble’s Sombrero Galaxy has a brilliant central bulge crossed by a dark dust lane. Webb’s mid-infrared view makes the bulge much less prominent and reveals a structured ring. The galaxy did not transform between the images; the instruments emphasise different material.
3 min read
NASA and The Hubble Heritage Team (STScI/AURA)
Webb’s observations of TRAPPIST-1 test a question that planet size alone cannot answer: which of its seven rocky worlds, if any, retain substantial atmospheres? The tightly packed system makes repeated measurements possible, but the small active star also contaminates the signals astronomers need.
4 min read
NASA/JPL-Caltech
Webb’s first reported spectrum of K2-18 b in 2023 prompted a question that later analyses made more demanding: which atmospheric molecules are securely identified, and which depend on how the small transit signal is processed? The answer determines how far any claim about the planet below can go.
3 min read
NASA, ESA, CSA, Joseph Olmsted (STScI); Science: Nikku Madhusudhan (IoA)
