The Met Office, the UK’s weather forecasting service, will begin to provide space weather forecasts for Earth, and weather forecasts for exoplanets. Presumably this is to ensure that when we set out on an interstellar journey to a planet orbiting Proxima Centauri, we want to make sure that it isn’t raining when we land. Just kidding.

The “space weather” forecasts are basically an upwards extension to the thermosphere, a region of atmosphere about 90-600 kilometers (55-370 miles) above Earth, immediately above the mesosphere (which weather forecasts already take into account), and below the exosphere. The International Space Station, with a low earth orbit of around 350km, resides in the thermosphere. The general idea is to measure space weather in the thermosphere so that we have a better idea of the electromagnetic interference that will eventually hit the Earth. As you might’ve read recently, the Sun is currently producing a huge solar flare that threatens to disrupt computers and communications satellites — by extending its weather model to the thermosphere, the Met Office hopes to predict and mitigate the damage from similar occurrences in the future.

Blue Marble 2012The forecasting of exoplanet weather is another thing entirely. Basically, a planet’s weather heavily depends on the star that it orbits — and so unsurprisingly the weather on planets in other solar systems can be very different from our own. “Most of the hundreds of extra-solar planets discovered to date are gas giants orbiting very close to their host star. These planets are strongly irradiated by the parent star, with one side experiencing permanent day and the other in permanent night,” says David Acreman, one of the astrophysicists working on the project. “The day side of the planet is much hotter than the night side and this temperature difference causes high speed winds to flow. These winds can be as fast as a few kilometers per second.”

As for why we’re attempting to forecast exoplanet weather, it’s all about science. These planets might have kilometer-per-second winds, but they’re still governed by the same physical laws on Earth. By analyzing the winds and temperature shifts, we can derive a better model of what the planets are actually like beneath the atmosphere. When it comes to studying Earth-like exoplanets that we might eventually visit, studying their weather might tell us if the planet is habitable, or indeed if there’s already signs of alien life. There’s a video of Acreman explaining exoplanet forecasting embedded below.

The Met Office Comms Room (they're probably dealing with output from the supercomputer)Both of these forecasting types will be built into the Unified Model, a weather and climate model developed by the Met Office, and used by forecasting agencies around the world. The Met Office, which was founded in 1854, is somewhat famous for being one of the first weather agencies, and one of the lynchpins of the British Empire. The development of a worldwide network of submarine cables and the electric telegraph meant that weather signals and warnings could be easily collated from and distributed to most of the world. The Met Office was also one of the first users of digital computers, and then later supercomputers.