Daily SumUp

The James Webb Space Telescope is helping scientists study a strange mass about 20 light-years from Earth. Traveling unpredictably through the cosmos, the mass is thought to be either a rogue planet or a "failed star," also known as a brown dwarf. Only a close examination of the body's atmosphere will determine which it is.

Astronomers first found SIMP 0136 back in 2003 using Sondage Infrarouge de Mouvement Propre (SIMP), a French term that translates to "infrared proper motion survey." This technique uses two telescopes on opposite hemispheres to capture the movement of a cosmic body in infrared. Strangely, SIMP 0136 appeared to be traveling freely and without a central star around which it could orbit. It also spun very quickly, despite being roughly the same size as Jupiter, making a single SIMP 0136 day only 2.4 hours on Earth.

This led astronomers to believe SIMP 0136 was a rogue planet, or a planet that floats freely through space. But there's a chance the mysterious mass could be something else entirely. Brown dwarfs, otherwise known as failed stars, are the result of gas clouds that have collapsed without gaining enough mass to initiate nuclear fusion—an essential step required to become a "true" star. Brown dwarfs have a minimum mass of 13 Jupiter masses (MJ) and SIMP 0136 has 12.7. SIMP 0136 also emits very little light, though these emissions seem to fluctuate, causing astronomers to be unsure about whether it fits within the brown dwarf category.