Knowledge Hub
Plain-language articles, research briefings and a glossary, written for curious readers at every level.
Knowledge Hub
Mars is red because its surface is rich in iron oxide, the same compound that makes rust. Billions of years ago the planet had liquid water and a thicker atmosphere, and iron in the rocks reacted with oxygen.
Fine dust blown by global storms spreads the reddish material across the planet, so even the sky looks butterscotch in daylight. Beneath the dust the rock is dark grey basalt.
Most exoplanets are found by watching a star’s brightness. When a planet passes in front of its star, the star dims slightly. The depth of the dip shows the planet’s size, and the time between dips shows how long its year is.
Another method measures the tiny wobble a planet’s gravity causes in its star. Combining the two gives both size and mass, and therefore density, which tells us whether a world is rocky or gassy.
A CubeSat is a small satellite built from standard 10 cm cubes, called units. A 3U CubeSat is three cubes long, roughly the size of a loaf of bread, and weighs a few kilograms.
Standard sizes mean standard launch dispensers and low costs, which is why universities and schools can fly real missions. CubeSats now carry out Earth observation, communications tests and science experiments.
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Landmark moments that changed what we know.
The Event Horizon Telescope imaged the shadow of the black hole at the centre of galaxy M87.
The infrared observatory began returning deep views of early galaxies and star-forming regions.
A spacecraft crashed into the moonlet Dimorphos and shortened its orbit around its companion by about 32 minutes.
OSIRIS-REx delivered material from a carbon-rich asteroid, giving scientists pristine samples from early Solar System history.
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What we know about ice in permanently shadowed craters and how it could be used.
How many objects are tracked in orbit, and what is being done about them.
The dose a crew might receive and the shielding options.
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Monthly sky maps for northern and southern observers.
Lesson plans and activities linked to curricula.
Worked problems in orbits, light and gravity.
Guided exercises with public telescope and satellite data.
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No match. Try a shorter word.
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Our video library is in production. These are the first series.
One sky event explained in sixty seconds.
How a mission works from idea to launch.
A tour of each world in the Solar System.
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About 384,400 km on average. Light takes roughly 1.3 seconds to travel that far.
Eight: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
The observable universe is about 93 billion light-years across. The whole universe may be larger, or infinite.
We have not found it yet. Astrobiology studies where and how to look, from Mars and ocean moons to planets around other stars.
Yes. The International Space Station is often brighter than any star and crosses the sky in a few minutes.