SpaceWhat causes auroras? How the northern lights get their colours
Discover how solar activity powers auroras, why oxygen and nitrogen produce different colours, and why a forecast cannot guarantee a sighting.
Space facts.
A closer look.
Planets, northern lights and questions from the cosmos. Start with a question below, then follow the evidence and further reading.
Space
SpaceIs a day on Venus longer than a year? The 243-day distinction
Venus rotates in about 243 Earth days and orbits in 225, but its solar day is about 117. Understand the difference with a simple calculation.
SpaceWhy do stars twinkle but planets usually do not?
Earth’s atmosphere bends starlight in shifting pockets of air. Learn why distant stars shimmer while nearby planets usually look steadier.
SpaceWhy does the Moon look bigger near the horizon?
The Moon does not physically grow near the horizon. The famous moon illusion comes from how the brain interprets its position and surroundings.
SpaceWhy don’t we feel Earth spinning?
Earth rotates rapidly, yet people do not feel the motion. The reason is constant motion, shared speed and gravity.
SpaceWhy do astronauts grow taller in space?
Without Earth’s usual compression, the spine can lengthen temporarily in orbit. The effect reverses after astronauts return.
SpaceHow can a black hole bend light?
Gravity curves spacetime. Near a black hole, that curvature can redirect passing light, create distorted images and sometimes form an Einstein ring.
SpaceWhy does the Moon have almost no atmosphere?
The Moon’s weak gravity and lack of strong global magnetic protection let gas escape more easily. It has an extremely thin exosphere rather than Earth-like air.
SpaceWhy can Saturn’s rings be seen so clearly?
Saturn’s rings are broad, bright bands of ice and rock particles. Their size, reflectivity and contrast against space make them visible even through modest telescopes.
SpaceWhy do comet tails point away from the Sun?
Solar wind and sunlight push material away from a comet’s nucleus. The tail follows the outward direction of those forces, so it can point differently from the comet’s path.
SpaceWhy is space black if the Sun is shining?
Space has very little material to scatter sunlight sideways. The sky looks bright from Earth because air redirects light into your eyes; without that atmosphere, a lit object sits against darkness.
SpaceWhy does the Sun look red at sunset?
At sunset, sunlight crosses a longer path through the atmosphere. Blue and violet light are scattered away more strongly, leaving more red and orange light along the direct path.
SpaceWhy does the Moon have phases?
The Moon is always half lit by the Sun. As it orbits Earth, we see different fractions of that sunlit half from our changing viewpoint.
SpaceWhy don’t eclipses happen every month?
The Moon’s orbit is tilted about five degrees relative to Earth’s orbit around the Sun. Most months the shadows pass above or below the alignment needed for an eclipse.
SpaceHow do astronauts drink water in space?
Astronauts use a recycling system that purifies humidity and wastewater. In microgravity, water forms floating spheres, so drinks are packaged in sealed containers with straws.
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