Our solar system has a wide variety of planet types, from tiny rocky Mercury to huge puffy gas giant Jupiter to distant ice giant Uranus. But beyond our own system, there are even more types of exoplanet out there, including water worlds covered in ocean and where life could potentially thrive. Now, researchers using the James Webb Space Telescope have identified a new and exotic type of planet called a steam world, which has an atmosphere almost entirely composed of water vapor.
The planet, called GJ 9827 d, was examined by the Hubble Space Telescope earlier this year and had researchers so intrigued that they wanted to go back for a closer look using Webb. They found that the planet, which is around twice the size of Earth, had a very different atmosphere from the typical hydrogen and helium that is usually seen. Instead, it was full of hot steam.
“This is the first time we’re ever seeing something like this,” said researcher Eshan Raul of the University of Michigan in a statement. “To be clear, this planet isn’t hospitable to at least the types of life that we’re familiar with on Earth. The planet appears to be made mostly of hot water vapor, making it something we’re calling a ‘steam world.'”
To look at the planet’s atmosphere, the researchers used Webb’s Near Infrared Imager and Slitless Spectrograph (NIRISS) instrument that can split light into different wavelengths to see what something is composed of in a technique called transmission spectroscopy. This is easier to do with lighter elements like hydrogen and helium, so being able to use this technique for a heavier element like water means scientists can now start to investigate more diverse planetary atmospheres.
“Now we’re finally pushing down into what these mysterious worlds with sizes between Earth and Neptune, for which we don’t have an example in our own solar system, are actually made of,” said fellow researcher Ryan MacDonald. “This is a crucial proving step towards detecting atmospheres on habitable exoplanets in the years to come.”
As this is such a new area of research, the discovery required new software written by the team so Raul, who is an undergraduate student, was the first person to see direct evidence that steam worlds existed.
“It was a very surreal moment,” said Raul, now a doctoral candidate at the University of Wisconsin-Madison. “We were searching specifically for water worlds because it was hypothesized that they could exist. If these are real, it really makes you wonder what else could be out there.”
The research is published in The Astrophysical Journal Letters.
After 13 suborbital test flights and more than $15 billion in development costs, SpaceX's Starship has finally reached orbit. The 407-foot megarocket, the most powerful ever built, lifted off from Starbase, Texas, on Monday and delivered its first real payload on it's 14th attempt. The celebration came with an asterisk, though, since SpaceX had to cut the planned 10-hour mission to roughly three hours.
https://twitter.com/SpaceX/status/2104601695711904180
SpaceX is finally ready to give Starship its biggest test yet. The company says the massive rocket's 14th test flight is scheduled for September 22, when it will attempt to put the upper stage into Earth orbit for the first time. The launch is currently pending regulatory approval, with a 75-minute window opening at 7:15 a.m. CT.
Starship has 26 Starlink satellites to deliver
For decades, humanity has looked up at the Moon and wondered what it would be like to live on it. Think sprawling cities, factories, research centers, and permanent human settlements. Unfortunately, there is one fairly fundamental problem with that vision.
A new study published in Frontiers in Space Technologies argues that even the Moon's potentially enormous reserves of frozen water may be nowhere near enough to support city-sized populations sustainably. Researchers Martin Elvis and Jonathan McDowell estimate that the permanently shadowed regions near the lunar poles could contain roughly one billion tons of water. It sounds like an extraordinary amount until you put a million thirsty humans next to it.