Controlled experiments are impossible in astronomy, as are direct measurements of physical properties of objects outside our solar system. So how do astronomers know so much about them?
A visualisation of the huge, glowing planetary body produced by a planetary collision.
Mark Garlick
Measuring the ages of planets and stars is tricky. An observational astrophysicist describes the subtle clues that provide good estimates for how old different space objects are.
The exoplanet K2-18b might host a water ocean.
Credits: Illustration: NASA, CSA, ESA, J. Olmsted (STScI), Science: N. Madhusudhan (Cambridge University)
New research suggests Saturn’s rings may be surprisingly young.
New research shows that the destructive merging of a star and a planet expels huge amounts of gas, as shown in this artist’s impression.
K. Miller/R. Hurt (Caltech/IPAC)
Stars begin to expand when they run out of fuel and can become thousands of times larger, consuming any planets in the way. For the first time, astronomers have witnessed one such event.
Vahe Peroomian, USC Dornsife College of Letters, Arts and Sciences
The dwarf planets in our Solar System are cold, dark, far away and full of surprises.
New research confirms how particles from space can be sent careening down into Earth’s atmosphere to create the aurora, filling in a missing piece in how this stunning natural phenomenon is generated.
Terry Zaperach/NASA
Clouds, hellish temperatures, endless nights? Characterizing the atmosphere of exoplanets, planets that orbit stars other than the sun, is a formidable task.
An artist’s impression of the exoplanet WASP-76b, which is hot enough to vaporize metals.
(European Southern Observatory/M. Kornmesser)
On the ultra-hot exoplanet WASP-76b, metal is vaporized in the heat. Studying the atmosphere of extreme planets will reveal more wild and weird weather.