Enjoying EarthSky? Subscribe.

138,328 subscribers and counting ...

Towering dust devil on Mars

A dust devil on Mars.

A dust devil on Mars. Image via HiRISE, MRO, LPL (U. Arizona), NASA.

Here’s a dust devil moving across the surface of the desert world Mars, late in the northern martian spring in the year 2012. Don’t be fooled by the perspective here. Martian dust devils are huge. This one stretches 12 miles (20 km) above the Martian surface. Its core measures about 140 meters (140 yards) in diameter. By contrast, earthly dust devils are only a few tens of meters high and a few meters across.

Smallest full moon of 2015 on March 5

near-apogee-full-moon-september-22-2010

Tonight’s full moon is the smallest full moon of the year. We’ve heard it called the micro-moon or mini-moon. It lies about 50,000 kilometers (30,000 miles) farther away from Earth than will the year’s closest full moon – the full supermoon and Northern Hemisphere’s Harvest Moon – on September 28.

Dusty galaxy in the early universe

This is the galaxy cluster Abell 1689.  It's so massive that its gravity bends and magnifies light coming  from more distant objects beyond it. That's how we can see the galaxy A1689-zD1 (in box). It’s a dusty galaxy seen when the universe was just 700 million years old. Image via NASA / ESA / L. Bradley, H. Ford, R. Bouwens, G. Illingworth.

This is the galaxy cluster Abell 1689. It’s so massive that its gravity bends and magnifies light coming from more distant objects beyond it. That’s how we can see the galaxy A1689-zD1 (in box). It’s a dusty galaxy seen when the universe was just 700 million years old. Image via NASA / ESA / L. Bradley, H. Ford, R. Bouwens, G. Illingworth.

When our universe came into being – some 13.8 billion years ago – there was no dust. The earliest galaxies didn’t have dust; they were made only of gas. That’s why the discovery of a dust-filled galaxy in the early universe is revealing to astronomers. It indicates to them that galaxies became quickly enriched with dust containing elements such as carbon and oxygen – the raw materials that go into making planets.

We’re genetically more like our fathers

Look like your mother? Act like your mother? Maybe so, but a new study says we mammals are more genetically similar to our fathers.

Northern spring is fireball season

Fireball!  Against the backdrop of the northern lights, no less.  Captured March 6, 2014 by Yuichi Takasake in Canada.

Fireball! Against the backdrop of the northern lights, no less. Captured March 6, 2014 by Yuichi Takasake in Canada.

Northern spring – for a few weeks around the March equinox – is a good time to see especially bright meteors, aka fireballs. It’s fireball season — a time of year when bright meteors appear in greater number than usual. In fact, in the weeks around the start of spring, the appearance rate of fireballs can increase by as much as 30 percent.

Star of the week: Pollux the brighter Twin star

You can see the comparative size of the star Pollux and our sun in this image, as well as some other stars.

You can see the comparative size of the star Pollux and our sun in this image, as well as some other stars.

The Greek letter Beta is normally reserved for the second-brightest star in a constellation. But Pollux wears the designation Beta in its constellation, even though it noticeably outshines Castor, which is Gemini’s Alpha star. Being so close together in the sky, Castor and Pollux are easy to compare. Pollux is golden, while Castor is white. Pollux is brighter than Caster. Follow the links inside for more about Pollux, the brighter Twin star.

Composites of October 8 moon eclipse

October 8, 2014 lunar eclipse composite by Michele Whitlow.

October 8, 2014 lunar eclipse composite by Michele Whitlow.

As the April 4 lunar eclipse approaches … some interesting composites from the last lunar eclipse.

Last of season’s 3 full moons on March 5

Photo credit: Jean-Baptiste Feldmann - photographies

Full moon via Jean-Baptiste Feldmann – Photographies

Tonight’s moon might look full, but the crest of the moon’s full phase comes on March 5, 2015 at 18:05 UTC, or 12:05 p.m. CST. This March full moon will be the third of 2015. It’ll be the Northern Hemisphere’s third and final full moon of winter and the Southern Hemisphere’s third and final full moon of summer.

How often does a solar eclipse happen on the March equinox?

Composite total solar eclipse Aug. 1999 by Fred Espenak.

A total solar eclipse is nature’s grandest spectacle. This composite image is by eclipse master Fred Espenak.

There’s a total solar eclipse coming up at this month’s equinox. When is the next one after this, and how often do we get an equinox-eclipse?

Methane-based lifeforms on Saturn’s moon?

A representation of a 9-nanometer azotosome, about the size of a virus, with a piece of the membrane cut away to show the hollow interior. Image credit: James Stevenson

A representation of a 9-nanometer azotosome, about the size of a virus, with a piece of the membrane cut away to show the hollow interior. Image credit: James Stevenson

Scientists offer a template for life that could thrive in the harsh, cold world of Titan, the giant moon of Saturn. It’s not life as we know it.