The salt in the sea has built up over billions of years – but it wouldn't have got there without freshwater rivers and streams.
Noctilucent clouds shine over Swaledale in the Yorkshire Dales, UK, June 2019.
Neil Squires/PA Wire/PA Images
'Night-shining' clouds normally found above the poles have now been seen as far south as Los Angeles.
A thunderstorm builds over the Karoo in South Africa.
Why is thunder so loud? It's because the amount of electrical energy that flows from the cloud to the ground is so enormous.
Sometimes air goes up past the condensation level then falls back below the condensation level, then up, then below, again and again. This creates clouds that are stripy, often with lines between the clouds.
Robert Lawry/Author provided
Clouds formed by rising warm air currents are called 'convection clouds'. Because of all the rising air coming up, these clouds can be bumpy on top, sometimes looking like cotton wool or cauliflower.
Even a small cloud can weigh as much as four tonnes – but gravity, chemistry and temperature keep them floating in the sky.
Asperitas cloud over Newtonia, Missouri, US.
© Elaine Patrick, Cloud Appreciation Society Member 31940.
Clouds can reveal a great deal about the world we live in. Here's what happens when scientists find a whole new type.
Cumulonimbus: heavy rain and thunder on the horizon.
The skies can tell us when there might be trouble ahead.
A blizzard in Steamboat Springs, Colorado, in 2005.
Governments and private companies have been seeding clouds to create snow for decades, without proof that it actually works. A recent study peered into clouds in search of answers.
Only clouds that are tall with big water drops can make rain, but they also stop most of the light, which makes them look grey.
Marcella Cheng/The Conversation
To answer this question from Fiona, age 6, we need to know some things about clouds and light.
Tiny CubeSats are ready to be our eyes in the skies.
Earth Background: NASA; HARP Spacecraft: SDL; Montage: Martins, UMBC
As technology advances, tiny satellites no bigger than a loaf of bread have advanced from just proving they work to being big contributors in answering science questions.
Iakov Kalinin / shutterstock
New study changes what we know about the pre-industrial atmosphere – and how we predict future climate change.
David Peter Robinson / shutterstock
While planes still emit too much carbon, they may also help the climate by ensuring clouds bounce more sunlight back into space.
Pieter Bruegel the Elder’s ‘The Tower of Babel’ (1563).
While translation technology has improved dramatically, there are some significant hurdles.
Stunning streaks of light can be seen in the polar regions during winter.
They may be stunning, but nacreous clouds are also contributing to the breakdown of the Earth’s ozone layer.
The Large Hadron Collider is playing a key role in enabling the collection of big data.
Big data is about processing large amounts of data. It is often associated with multiplicities of data. But the ability to generate data outpaces the ability to store it.
Understanding clouds is crucial to understanding whether temperatures will rise quickly in coming decades.
The amount of global warming we can expect in the future has been a tough question to pin down. A new study that I led with colleagues in France has enabled us to come up with a more accurate analysis…
Clouds caused by air pollution have been overestimated in their ability to to reflect sunlight back into space, thus helping…
Cloud formation is not affected by organic particles attached to water droplets, researchers at the Georgia Institute of…
Cloud height has declined by 30-40 meters from 2000 to 2010. The analysis was based on the first 10 years of data collected…
CERN’s work casts light on cloud formation, but might not have much to say about climate change.
Physicists at CERN (the European Organization for Nuclear Research) created something of an online kerfuffle last month when they sought to improve our understanding of cosmic rays and clouds. While their…