The Sun tab
Space weather, the solar wind, sunspots, live images of the Sun and time-lapses.
Aurora starts at the Sun. The Sun tab shows what's coming before it reaches Earth. It has three sections: Space weather, Solar activity and The Sun now. On a phone each one is folded to a one-line summary; tap its title to open it.
Space weather
The solar wind right now, measured about 1.5 million km towards the Sun, so changes reach Earth 30 to 60 minutes later:
- IMF Bz: the main switch for aurora. When Bz points south (negative), energy pours in.
- Speed and Density: faster, denser wind pushes harder on Earth's magnetic field.
- Hemi power: how much energy the aurora is putting into the atmosphere.
Tap the i in a card's corner for a short, simple explanation of everything on it.
Solar activity
Chaser shows the same four as graphs over the last 24 hours, so you can see a storm building before Kp catches up.
The Sun now
- Sunspot regions: the numbered regions on today's Sun, with their magnetic class and NOAA's chance of an M-class or X-class flare from each.
- Sun images: live pictures of the Sun from NASA, ESA and NOAA spacecraft, in different wavelengths. Tap one to enlarge it, then swipe for the next.
- Time-lapse: choose a View and a Time span of 1 day, 7 days or 27 days (one full turn of the Sun), and tap play.
The newest images can be an hour or more old. See Why are the Sun images an hour old?