A New Model Explains How Gas and Ice Giant Planets Can Form Rapidly

The most widely recognized explanation for planet formation is the accretion theory. It states that small particles in a protoplanetary disk accumulate gravitationally and, over time, form larger and larger bodies called planetesimals. Eventually, many planetesimals collide and combine to form even larger bodies. For gas giants, these become the cores that then attract massive …

Do Planets Have the Raw Ingredients for Life? The Answer is in their Stars

Finding planets that already have, or have the ingredients for intelligent life is a real challenge. It is exciting that new telescopes and spacecraft are in development that will start to identify candidate planets. Undertaking these observations will take significant amounts of telescope time so we need to find some way to prioritise which ones …

If We Want To Find Life-Supporting Worlds, We Should Focus on Small Planets With Large Moons

There’s no perfect way of doing anything, including searching for exoplanets. Every planet-hunting method has some type of bias. We’ve found most exoplanets using the transit method, which is biased toward larger planets. Larger planets closer to their stars block more light, meaning we detect large planets transiting in front of their stars more readily …

TRAPPIST-1 Outer Planets Likely Have Water

The TRAPPIST-1 solar system generated a swell of interest when it was observed several years ago. In 2016, astronomers using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) at La Silla Observatory in Chile detected two rocky planets orbiting the red dwarf star, which took the name TRAPPIST-1. Then, in 2017, a deeper analysis found another five rocky planets. It was …

The Giant Planets Migrated Between 60-100 Million Years After the Solar System Formed

Untangling what happened in our Solar System tens or hundreds of millions of years ago is challenging. Millions of objects of wildly different masses interacted for billions of years, seeking natural stability. But its history—including the migration of the giant planets—explains what we see today in our Solar System and maybe in other, distant solar …

Finding Atmospheres on Red Dwarf Planets Will Take Hundreds of Hours of Webb Time

The JWST is enormously powerful. One of the reasons it was launched is to examine exoplanet atmospheres to determine their chemistry, something only a powerful telescope can do. But even the JWST needs time to wield that power effectively, especially when it comes to one of exoplanet science’s most important targets: rocky worlds orbiting red …

Webb Sees a System That Just Finished Forming its Planets

When a young star begins forming, it’s spinning rapidly, surrounded by a flattened disk that grows its future planets. Once the star can ignite fusion in its core, its stellar winds kick in, clearing out the remaining gas and dust, starving its planets for material. Now, JWST has found an older star in this exact phase of the cycle, dispersing its gas into interstellar space. This limits how much larger the planets can become until no material remains.

How We Get Planets from Clumping Dust

Our gleaming Earth, brimming with liquid water and swarming with life, began as all rocky planets do: dust. Somehow, mere dust can become a life-bearing planet given enough time and the right circumstances. But there are unanswered questions about how dust forms any rocky planet, let alone one that supports life.