Magazine
March-April 2026
March-April 2026
Volume: 114 Number: 2
A deep photographic exposure captures a time-lapsed view of 3I/ATLAS, an interstellar object and only the third large one confirmed to have passed through our Solar System from elsewhere. 3I/ATLAS has a bright dust tail (color enhanced in this image) that is typical of comets. However, the prior two interstellar objects were quite different, showing the range of small bodies in the universe. The first interstellar object detected, 1I/ʻOumuamua, did not have a dust tail but had unexpected accelerations not caused by gravity that were too strong to be from forces created by radiation. As Darryl Z. Seligman describes in “The Discovery of Dark Comets,” studying this strange interstellar object inspired him and his colleagues to take a closer look at comets in the Solar System that also seem to defy standard definition, and which might belong to an entirely new astronomical category. (Cover image by Dan Bartlett.)
In This Issue
- Astronomy
- Biology
- Chemistry
- Communications
- Computer
- Engineering
- Environment
- Ethics
- Evolution
- Medicine
- Physics
- Policy
- Psychology
- Technology
Looking Through the Eye and into Alzheimer’s Disease
Peter Jeffrey Snyder
Medicine
The retina can reveal subtle signs of disease long before cognitive and behavioral symptoms appear.
Mantle Waves
Thomas Gernon, Sascha Brune
Chemistry Physics
A hidden geological process reframes our understanding of how diamonds erupt and continents evolve.
