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Moon at perigee, nearest to Earth, on July 5, 2015

The waning gibbous moon (55% illuminated as seen from Earth) on the morning of June 9, 2015 via EarthSky Facebook friend Deirdre Horan in Dublin, Ireland.

The waning gibbous moon (55% illuminated as seen from Earth) on the morning of June 9, 2015 via EarthSky Facebook friend Deirdre Horan in Dublin, Ireland.

In July 2015, the moon sweeps to perigee – the moon’s closest point to Earth for the month – on July 5 at 18:54 UTC. That is July 5 at 1:54 p.m. CDT. The moon at this perigee lies 367,093 kilometers (228,101 miles) from Earth. We list the dates for this year’s 13 lunar apogees (farthest points) and 13 lunar perigees (nearest points), inside. . .

Incredible color-changing! How does octopus do it?

Here’s a different kind of color explosion for the holiday. How and why the octopus, squid, and cuttlefish change colors.

Scorpius? Here’s your constellation

The constellation Scorpius and the <a href='http://earthsky.org/favorite-star-patterns/teapot-of-sagittarius-points-to-galactic-center

The constellation Scorpius.

Scorpius the Scorpion – the southernmost constellation of the Zodiac – is a major showpiece of the starry sky. The constellation is easy to find. It looks like its namesake. Follow the links inside to learn more.

What makes Venus the brightest planet?

Venus and Jupiter in conjunction on June 30, 2015, as captured by Mohamad Fadzli in Melaka, Malaysia.

Venus and Jupiter in conjunction on June 30, 2015, as captured by Mohamad Fadzli in Melaka, Malaysia.

Venus is much brighter than any other planet viewed in Earth’s sky. It’s the third-brightest object in the sky, after the sun and moon, and right now it’s heading for another time of greatest brilliancy around July 10, 2015. Click the links inside to learn why Venus is so bright, and when to see it as its brightest in 2015.

Summer Triangle: Vega and its constellation Lyra

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More than any other month, July is the month of the Summer Triangle, made up of the brilliant stars Vega, Deneb and Altair. The brightest triangle star is Vega in the constellation Lyra. Vega is blue-white in color. It’s sometimes called the Harp Star.

How do fireworks get their colors?

Photo credit: Jeff Golden

Photo credit: Jeff Golden

If you’re celebrating the 4th of July by attending a fireworks display, maybe you’ll look up and wonder: What creates those red, orange, yellow, green, blue and purple colors exploding in the night sky?

Stars’ spiral arms cradle baby planets

Astronomer Alan Boss' theoretical model of a protoplanetary disk around a young star.  Notice the spiral structure. Image via Carnegie Institution for Science.

A protoplanetary disk around a young star, from a new theoretical model by astronomer Alan Boss. Notice the spiral structure extending outward from the central star. Image via Carnegie Institution for Science.

A new study from the Carnegie Institution for Science in Washington D.C. offers a potential solution to the question of how small rocky planets like our Earth come to be. A puzzle relates to how dust grains in a disk around a newly forming star avoid being dragged into the star before enough of the grains stick together to have strong-enough gravity to begin pulling in more grains … and ultimately grow into planets.

Star of the week: Antares is Heart of the Scorpion

Red star Antares, right, and nearby star cluster M4 via StargazerBob.com@aol.com

Red star Antares, right, and nearby star cluster M4 via StargazerBob.com@aol.com

Bright reddish Antares – also known as Alpha Scorpii – is easy to spot on a summer night. It is the brightest star – and distinctly reddish in color – in the fishhook-shaped pattern of stars known as the constellation Scorpius the Scorpion. Follow the links inside to learn more about this wonderful star.

Find M4, a globular cluster by the Scorpion’s heart

Messier 4 or M4 from European Southern Observatory.

Messier 4 or M4 from European Southern Observatory.

At nightfall, look in your southern sky for the bright ruddy star that is called the Scorpion’s Heart – Antares, the brightest star in the constellation Scorpius. Antares is always up on summer evenings. It’s a bright red star known for twinkling rapidly. If you have binoculars, sweep for an object near Antares on the sky’s dome. This object is called M4, and it’s a globular star cluster located just one degree to the west of Antares.

Mercury and more before dawn

Mercury, Aldebaran, Pleiades on June 30, 2015 by Ken Christison.

Planet Mercury, star Aldebaran, Pleiades star cluster on June 30 by Ken Christison in Conway, North Carolina.

Ken Christison caught Mercury in the east before dawn this week. He couldn’t see it with the eye that day, but you might see it, if you look. Details inside.