| | | September 22 Happy Equinox | | | |
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Equinoxes and solstices. In each of the images, Earth’s rotational axis is perpendicular (straight up and down), with the North Pole at top and South Pole at bottom. Earth at the equinoxes shown at right; Earth at solstices shown at left. Images via Geosync. | | | | | | | | A new way to launch rockets without fuel? | | | Conventional rockets - with their onboard fuel - are expensive and dangerous. A new concept called quantized inertia might make rocket launches cheaper and safer. The concept has just received $1.3 million in new funding. Read more. | | | | | | | |
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|  | | | Equinox sun is over Earth's equator | | At the instant of the September equinox - the sun is at zenith, or straight overhead, as seen from Earth’s equator. Read more. | | | | | |
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 | | Twilight returns to the South Pole | "As twilight brightens before the equinox sunrise at the South Pole, the blue-grey shadow of the Earth descends to the horizon, the last vestige of the polar night." Twitter photo via Robert Schwarz (@iceman_90South)/The Antarctic Report (@AntarcticReport). | | |
