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Deborah Byrd

Cloud-to-cloud shadow over China

One morning over Hong Kong, a striking shadow cast from one cloud to another. Photos by Cammy Li. Explanation by Matthew Chin.

Messier 33: 2nd-closest spiral galaxy

Triangulum galaxy, aka Messier 33. is 2.7 million light-years away, and the 3rd-largest member of our Local Group, after the Milky Way and Andromeda galaxies.

Last night’s moon, Saturn, Mercury

If you’ve been watching the west after sunset, you know the young moon is back. It has swept past the planets Saturn and Mercury and still hovers not far from them, with its lighted face pointed toward them.

Flowing sand, not water, on Mars

The dark streaks on Mars known as recurring slope lineae are likely the result of repeated avalanches of sand and dust, rather than seeping water, new research shows.

Fern, contrail shadow, singing dunes

It was a beautiful day for natural phenomena in the sky, and on the ground.

It’s the 1st known interstellar asteroid

It swept nearest the sun in September, then sped away again, back to interstellar space. Astronomers named it `Oumuamua. It’s dark red, very elongated and unlike anything in our solar system.

Today in science: Edwin Hubble and the expanding universe

Learn why the Hubble Space Telescope is named for this astronomer.

Next new moon is December 17-18

A new moon is a moon most nearly between the Earth and sun for any particular month. It crosses the sky with the sun during the day.

Where’s the moon? Waxing crescent

Many photos of Sunday evening’s extremely thin and lovely young moon. A few glimpsed it near Mercury and Saturn, too. Watch for the waxing crescent in the evenings ahead.

Jupiter’s independently pulsating auroras

The auroras over Earth’s north and south poles typically mirror each other. But X-ray observations show that Jupiter’s auroras pulsate on different timescales.