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Look for moon and Venus before dawn on April 25

2014-april-24-venus-moon-night-sky-chart

It’ll be worth waking up before sunrise on April 25 to see the waning crescent moon and the planet Venus in the early morning sky. Look eastward – in the direction of sunrise – and you can’t miss this brilliant twosome at dawn. After all, the moon and Venus rank as the second-brightest and third-brightest heavenly bodies, after the sun.

First sex-determing genes appeared 180 million years ago

Image credit:

Image credit: ntr23

The Y chromosome, which distinguishes males from females at the genetic level, appeared some 180 million years ago, according to a new study published in Nature.

6.6-magnitude earthquake off Vancouver Island on April 23

April 23, 2014 earthquake

April 23, 2014 earthquake

The U.S. Geological Survey reported a strong, 6.6-magnitude earthquake Wednesday night (April 23, 2014) in the Pacific Ocean off the northwest corner of British Columbia’s Vancouver Island. The quake hit at 8:10 p.m. local time. There were no immediate reports of damage or injuries. No tsunami warning was issued.

The quake was followed by aftershocks of magnitude 5.0 and 4.2, the USGS said.

This part of Canada is located along what geologists call the Ring of Fire, one of the most geologically active areas on Earth and a site for frequent earthquakes and powerful volcanic eruptions.

The zodiacal light, seen from the moon

Zodiacal light seen from the moon by NASA's LADEE spacecraft, which crashed into the moon on April 17.  Image via NASA Ames and Emily Lakdawalla.

Zodiacal light seen from the moon by NASA’s LADEE spacecraft, which crashed into the moon on April 17. Image via NASA Ames and Emily Lakdawalla.

NASA’s robotic moon explorer, LADEE, crashed into the back side of the moon, as planned, on April 17, 2014. Just five days earlier, it captured this amazing imagery of the zodiacal light as seen from the moon’s vicinity. Looks a bit like twilight, doesn’t it? But remember, although twilight here on Earth is an atmospheric phenomenon, this is the moon, and the moon has no air.

Star of the week: Spica is a whirling double star

Daniel McVey captured this image of planet Mars and star Spica on March 26, 2014.

Daniel McVey captured this image of planet Mars and star Spica on March 26, 2014.

Spica looks like one star, but it is at least two stars, both larger and hotter than our sun, orbiting only 18 million kilometers (11 million miles) apart. That’s in contrast to 150 million kilometers for Earth’s distance from our sun. Their mutual gravity distorts each star into an egg shape, with the pointed ends facing each other as they whirl around, completing a single orbit in only four days. Follow the links inside to learn more about Spica, brightest star in the constellation Virgo the Maiden, near Mars in 2014.

What is a Blood Moon?

This is what a total eclipse looks like.  This is the total eclipse of October 27, 2004 via Fred Espenak of NASA, otherwise known as Mr. Eclipse.  Visit Fred's page here.

This is what a total eclipse looks like. This is the total eclipse of October 27, 2004 via Fred Espenak of NASA. Visit Fred’s page here. We astronomy writers often describe a totally eclipsed moon as appearing ‘blood red.’ Here’s why the moon turns red during a total eclipse.

The first Blood Moon eclipse in a series of four happened on the night of April 14-15, 2014. The next one will be on the night of October 7-8, 2014.

Halo around the sun over Normandy, France

EarthSky Facebook friend Jean Marie Andre Delaporte captured this image of a halo around the sun in Normandy, France on April 23, 2014.

EarthSky Facebook friend Jean Marie Andre Delaporte captured this image of a halo around the sun in Normandy, France on April 23, 2014.

We get many messages throughout each year from people who’ve just spotted a halo, or ring, around the sun or moon. They’re caused by both refraction, or splitting of light, and also by reflection, or glints of light from ice crystals high in Earth’s atmosphere. The crystals have to be oriented and positioned just so with respect to your eye, in order for the halo to appear.

Is spacetime like a liquid?

Image credit: SISSA Medialab

Image credit: Jason Ralston

What if spacetime were a kind of fluid? This is the question tackled by theoretical physicists working on quantum gravity by creating models attempting to reconcile gravity and quantum mechanics. Some of these models predict that spacetime at the Planck scale is no longer continuous – as held by classical physics – but discrete in nature, like the solids or fluids we come into contact with every day, which can be seen as made up of atoms and molecules.

EarthSky’s meteor shower guide for 2014

Mike O'Neal posted this on the EarthSky Facebook page today (April 22).  He wrote, 'Had mostly cloudy sky, but did see some beautiful ones between the breaks.'

Mike O’Neal posted this shot of a Lyrid meteor on the EarthSky Facebook page at last year’s shower, on April 22, 2013. He wrote, ‘Had mostly cloudy sky, but did see some beautiful ones between the breaks.’

The Lyrid shower has mostly passed, but you might still see some stray meteors. Try watching from midnight to dawn on the mornings of April 24-26, 2014. Here’s the good news. The moon is waning and appearing in the sky for fewer hours of the night. So although meteor rates will be way down in contrast to earlier this week, you’ll have a better shot at seeing faint meteors in moonless sky.

Everything you need to know: Eta Aquarid meteor shower

Photo by Justin Ng

Eta Aquarid meteor in the 2013 shower over Mount Bromo, an active volcano in Indonesia. Photo by Justin Ng in Singapore.

A meteor shower is coming up in early May 2014 that should make our friends in the Southern Hemisphere very happy. The Eta Aquarid shower, which peaks before dawn May 5-7, is a fine one to view from tropical and southerly latitudes. At mid-northern latitudes, these meteors don’t fall so abundantly, though mid-northern meteor watchers will catch some, too, and might be lucky enough to catch an earthgrazer – a bright, long-lasting meteor that travels horizontally across the sky – before dawn. Because the Eta Aquarids are mainly a predawn shower, the waxing moon in early May will have set before the Eta Aquarid meteors start to streak the nighttime sky. Follow the links inside to learn more about the Eta Aquarid meteor shower.