The Rhythm of the Spheres

Reading the Night Sky

Wandering in Astronomy

The night sky is the oldest pattern of man, and every culture reads it differently. The stars above keep silent time, moving to a rhythm we are just now beginning to understand. Astronomy is where math, science, art, music, and words meet in a wondrous collision. In this section of our site, learn the basics of astronomy: from how a star chart is made, to projections and art that map the night sky, to how an astrolabe works just like it did thousands of years ago. Watch the North Star shift across centuries, explore how one sky has been mapped by many traditions, read what happened on this day in space, and see tonight’s moon for your location.

Map the Stars

The math behind star charts, with a projection explorer and a working astrolabe.

The Moving Sky

How the sky shifts across centuries, with a precession clock you can run.

The Traditions

One sky reads many ways, with a same-sky overlay of the world’s constellations.

This Day in the Stars

The sky’s events, discoveries, and lore tied to today’s date.

The Moon Tonight

Its phase and face, drawn live for where you’re standing.

✦  Astronomy Picture of the Day  ✦

Earth's Richat Structure

May 19, 2013
What on Earth is that? The Richat Structure in the Sahara Desert of Mauritania is easily visible from space because it is nearly 50 kilometers across. Once thought to be an impact crater, the Richat Structure's flat middle and lack of shock-altered rock indicates otherwise. The possibility that the Richat Structure was formed by a volcanic eruption also seems improbable because of the lack of a dome of igneous or volcanic rock. Rather, the layered sedimentary rock of the Richat structure is now thought by many to have been caused by uplifted rock sculpted by erosion. The above image was captured by the ASTER instruments onboard the orbiting orbiting Terra satellite. Why the Richat Structure is nearly circular remains a mystery.

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✦  EarthSky  ·  Astronomy.com  ·  Phys.org  ✦
Astronomy Aug 31, 2026

JWST reveals likely Type II supernova from when universe was only 2 billion years old

Astronomers using the James Webb Space Telescope have identified one of the most distant exploding stars ever confirmed. The supernova, SN 2023aeaf, was found at a redshift of 3.195—so far away t…

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Human Spaceflight Aug 31, 2026

Why do astronauts get constipated?

Try and try and try as they may, scientists have yet to explain one of spaceflight’s most painfully enduring mysteries: Why do astronauts get constipated? After examining blood samples from 52 as…

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Today in the History of Astronomy Aug 31, 2026

Aug. 31, 1913: Birth of Bernard Lovell

On Aug. 31, 1913, Alfred Charles Bernard Lovell was born in England. When he was 15, a school trip to hear a lecture on electricity prompted a keen interest in science and math, and Lovell would go…

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Earth Aug 31, 2026

Giant trees break a decades-old science theory

Giant trees have evolved remarkable adaptations that allow them to reach extreme heights while maintaining efficient water transport.

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Astronomy Aug 31, 2026

JWST may solve a 20-year mystery behind a rule-breaking gamma-ray burst

Astronomers may have finally solved the mystery behind a nearly two-decade-old cosmic explosion that seemed to break the rules of physics. The energy output of a powerful gamma-ray burst, GRB 06120…

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Earth Aug 31, 2026

Lake Powell hits record low, continues to drop

Lake Powell has hit its lowest level ever. Despite the monsoons, like the flash floods that hit Grand Canyon over the weekend, water levels continue to drop.

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Sun Aug 31, 2026

Sun news: Fast coronal hole winds now easing

Sun news August 31, 2026: A coronal hole's wind disturbed our magnetic field before fading. Meanwhile, a big filament erupted in the northeast.

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Observing Aug 31, 2026

The Sky Today on Monday, August 31: Venus and Spica gather close

Looking for a sky event this week? Check out our full Sky This Week column.  August 30: The Moon, Neptune, and Saturn In the evening sky, blazing Venus is less than 2° southwest of …

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Astronomy Aug 31, 2026

The SKA project: A model for dialogue between historical astronomical archives, local memory and modern science

Humans have been observing the sky for thousands of years. Our ancestors were undoubtedly fascinated by it, but observing the heavens also had practical uses: It helped people measure time, both ov…

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