sun

In May 2024, auroras appeared over Florida, the Yucatán Peninsula, and Puerto Rico. Northern lights were photographed from latitudes that had not seen them in decades — triggered by the strongest geomagnetic storm since March 1989. The storm was rated G5, the maximum on NOAA's five-point geomagnetic disturbance scale. Solar Cycle 25, which government forecasters had predicted would be 'average,' had quietly become one of the most active solar cycles in a century — and the official models did not see it coming until it was already happening.

How the Sun works: proton-proton fusion in the core, layers from radiative zone to corona, solar wind, sunspots, and the Sun's far future.

Solar vs lunar eclipses: types, why they don't happen every month, the Saros cycle, famous eclipses, and how to watch safely.

NASA's Parker Solar Probe is the first spacecraft to fly inside the Sun's corona — here's what it has found and why it matters.

If the Sun vanished right now, we'd have 8 minutes of sunlight left. Then darkness, plummeting temperatures, and Earth drifting into interstellar space.

A powerful solar storm could knock out global power grids and satellites. Neural networks are our early warning system against the Sun's most destructive outbursts.

How detecting neutrinos from the sun revealed fundamental physics mysteries

If the Sun were swapped for a black hole of the same mass, Earth's orbit would not change at all. The danger is the lost sunlight, which would turn the surface into a frozen, lightless world.

The Sun will exhaust its hydrogen fuel in approximately 5 billion years, expanding into a red giant large enough to engulf Mercury and Venus — and possibly Earth. It will then shed its outer layers as a planetary nebula, leaving behind a white dwarf that will cool for trillions of years. Humanity has approximately 1 billion years before rising solar luminosity makes Earth uninhabitable.

The heliosphere is a vast bubble of solar wind plasma around the Sun, reaching roughly 120 AU toward the direction we are moving. It deflects a large share of low-energy galactic cosmic rays. Voyager 1 crossed its outer boundary, the heliopause, in 2012 and Voyager 2 followed in 2018.

Solar flares, coronal mass ejections, and geomagnetic storms are not science fiction. They have knocked out power grids before, and the next big one could be far worse.

If the Sun stopped shining tomorrow, Earth would still feel its gravity but lose its energy. Here's what would actually happen — minute by minute, day by day, month by month.