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Amazing Mercury close up

Image via NASA / JHU / APL MESSENGER spacecraft.

Image via NASA / JHU / APL MESSENGER spacecraft.

The MESSENGER spacecraft acquired this image of Mercury on January 23, 2015, at a time when this part of Mercury was near sunset. It’s one of the highest-resolution images yet obtained of Mercury.

The 2015 Great Backyard Bird Count starts February 13

Common redpoll. Image Credit: Seabamirum via Flickr.

Common redpoll. Image Credit: Seabamirum via Flickr.

This year’s Great Backyard Bird Count runs from February 13 to February 16. It’s free and easy to participate. Find out how here.

This date in science: When a spacecraft destroyed a sundog

The coolest space launch ever! Watch what happened when a spacecraft launch destroyed a sundog, in the process bringing to light a new form of ice halo. Full story inside.

New half-life for iron-60 gives astronomers a better clock

Artist's illusration of a supernova via SmithsonianScience.org

Artist’s illustration of a supernova via SmithsonianScience.org. The new measurement for the half-life of iron-60 relates to the dates of certain cosmic events, for example, nearby supernovae.

Australian researchers get a new, more accurate half-life for iron-60, thereby making immeasurable time less so.

How far is Betelgeuse?

 Betelgeuse imaged in ultraviolet light by the Hubble Space Telescope and subsequently enhanced by NASA. The bright white spot is likely one of this star's poles. Image via NASA/ESA.

Betelgeuse imaged in ultraviolet light by the Hubble Space Telescope. Image via NASA/ESA.

Recently I realized that the distance I used for the star Betelgeuse – ninth-brightest star in the night sky and second-brightest in the constellation Orion the Hunter – in a popular blog post here at EarthSky has become outdated. I thought that this would be good time to mention how star distances are determined, while correcting Betelgeuse’s distance estimate. Truth is, finding the distances to even the nearest stars is not easy.

This date in science: Great Meteor Procession

Canadian artist Gustav Hahn painted his impression of what the Great Meteor Procession looked like, in 1913. Image via Gustav Hahn/University of Toronto Archives. Used with permission.

February 9, 1913. On this date, a strange meteor sighting occurred over Canada, the U.S. Northeast, Bermuda and some ships at sea, including one off Brazil. What happened that night is sometimes called the Great Meteor Procession of 1913, and it sparked decades of debate concerning what actually happened.

Have astronomers pinpointed dark matter Galaxy X?

This image is a 2007 supercomputer simulation illustrating dark matter satellites as bright clumps around our Milky Way galaxy. Image via stanford.edu

This image is from a 2007 supercomputer simulation. The bright clumps illustrate dark matter satellite galaxies around our Milky Way galaxy. Many large galaxies like the Milky way are now believed to have dark matter satellites. Image via stanford.edu

Dark matter hunters announced this week that they may have located a previously unseen dark-matter-dominated dwarf galaxy – a satellite to our home galaxy, the Milky Way – on the far side of our galaxy. They’ve been speculating about just such a galaxy, nicknamed Galaxy X, for several years. Evidence for it came originally from a 2009 analysis of ripples in the Milky Way’s outer disk. The latest study – led by astronomer Sukanya Chakrabarti – points to a cluster of four young, pulsating stars approximately 300,000 light-years away. Those stars might mark the location Galaxy X.

Hello, Pluto! New images from New Horizons

Pluto and Charon, the largest of its five moons, as seen by New Horizons.   Image via NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

Pluto and Charon, the largest of its five moons, as seen by New Horizons. Image via NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

Now things are about to get exciting! On February 4, 2015 – 109th anniversary of the birth of Clyde Tombaugh, who discovered Pluto in 1930 – NASA released new images of Pluto and its largest moon Charon. The New Horizons’ spacecraft telescopic Long-Range Reconnaissance Imager (LORRI) captured the images this past January 25 and 27. New Horizons was about 126 million miles (203 million km) from Pluto when LORRI acquired the frames to make the first image. The spacecraft was 1.5 million miles (2.5 million km) closer two days later, for the second set of frames. Closer and closer, the spacecraft will finally sweep through the Pluto system on July 14 of this year.

NASA steps closer to a Europa mission

A composite of Europa made from images from the Galileo spacecraft, which orbited in the jovian system for eight years, beginning in 1995.  Image via NASA/JPL

A composite of Europa made from images from the Galileo spacecraft, which orbited in the jovian system for eight years, beginning in 1995. Areas that appear blue or white contain relatively pure water ice. Image via NASA/JPL

This week, as Earth passes between the sun and Jupiter and the giant planet looms brightest in our sky for 2015, the space community is buzzing with news of positive steps toward NASA’s planned mission to Jupiter’s fascinating moon Europa. The mission is called Europa Clipper.

This date in science: Maarten Schmidt’s revelation about quasars

Maarten Schmidt is a Dutch astronomer who, in 1963, recognized that quasars are located in the very distant universe, and therefore must be extremely powerful energy sources.

February 5, 1963. On this date, Maarten Schmidt had a revelation that showed that quasars are exceedingly distant and unimaginably luminous. It changed our notion of what our universe is like.