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Aerosols from Chile’s Calbuco volcano reach Africa

Volcanic sunset on May 3, 2015 at 5:42 p.m. in Mutare, Zimbabwe.  Photo by Peter Lowenstein.

A bright orange glow at sunset on May 3, 2015 – 5:42 p.m. – as captured in Mutare, Zimbabwe. The unusual colors are typical of volcanic sunsets, in this case due to aerosols from Chile’s Calbuco volcano. Photo by Peter Lowenstein.

Last week, EarthSky published a series of photos of dramatic sunsets in Brazil, caused by the April 22 eruption of Chile’s Calbuco volcano. On Sunday afternoon – May 3, 2015 – we heard from Peter Lowenstein in Mutare, Zimbabwe, who said that the aerosols from this volcanic eruption have now crossed the South Atlantic and are causing dramatic sunsets in African skies.

Why do we celebrate May Day?

Happy May Day!

May Day is an ancient spring festival in the Northern Hemisphere. It’s an astronomical holiday, one of the year’s four cross-quarter days, or day that falls more or less midway between an equinox and solstice.

MESSENGER ends mission, crashes into Mercury

Predicted ground approach track of MESSENGER's Mercury impact on April 30, 2015.

Predicted ground approach track of MESSENGER’s Mercury impact on April 30, 2015.

UPDATE APRIL 30 AT 4 P.M. CDT (21OO UTC): Mission controllers at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, have confirmed NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft impacted the surface of Mercury, as anticipated, at 3:26 p.m. EDT.

Why do global temperature records differ?

Graph via NASA GISS

Graph via NASA GISS

Why do different institutions – NASA, NOAA, and the Japanese Meteorological Agency – publish slightly different global temperature measurements?

Carbon from melting permafrost goes back to atmosphere

Kolyma region in the Siberian Arctic. Image Credit: Anatoly V. Lozhkin.

Kolyma region in the Siberian Arctic. Image Credit: Anatoly V. Lozhkin.

According to a new study, microbes eat the carbon and release it as CO2, where ends up back in the atmosphere and contributes to further warming.

What is dark energy?

How do we think about something we can’t see and don’t experience in our everyday lives, but seems to be pushing our universe apart ever faster? Image credit: NASA, ESA, G. Illingworth, D. Magee, and P. Oesch (University of California, Santa Cruz), R. Bouwens (Leiden University), and the HUDF09 Team, CC BY

How do we think about something we can’t see and don’t experience in our everyday lives, but seems to be pushing our universe apart ever faster? Image credit: NASA, ESA, G. Illingworth, D. Magee, and P. Oesch (University of California, Santa Cruz), R. Bouwens (Leiden University), and the HUDF09 Team, CC BY

Instead of pulling galaxies in our universe together, gravity seems to be driving them apart. How can gravity be repulsive, when our everyday experience shows it’s attractive? That’s why we need dark energy …

First visible light spectrum from exoplanet

Artist's concept of 51 Pegasi b orbiting its parent star.  Image via Dr. Seth Shostak/SPL.

Artist’s concept of 51 Pegasi b – sometimes unofficially called Bellerophon. It was the first exoplanet found orbiting a sunlike star. Now the first direct spectrum of light reflected from an exoplanet’s surface has been obtained from 51 Pegasi b. Image via Dr. Seth Shostak/SPL.

Why are astronomers excited about the first directly obtained visible light spectrum – or rainbow array of visible colors – bounced from the surface of an exoplanet? Look inside.

What’s the real deal with shark attacks?

Photo credit: C. Fallows

Photo credit: C. Fallows

Sharks are incredibly unlikely to bite you. They’re even less likely to kill you. However, we remain fascinated with their ability – and occasional proclivity – to do just that.

Ocean acidification drove Earth’s largest mass extinction

Computer artwork via the BBC

Computer artwork via the BBC

During the Permian–Triassic mass extinction event 252 million years ago, most life on Earth perished. Scientists have now obtained evidence that ocean acidification played a key role in the die-off.

Shortest lunar month of 2015 starts April 18

Simulated view of the cycle of the moon's phases from new moon to new moon. This cycle is known as the lunar month. From the years 1760 to 2200, the longest lunar month was 29 days 19 hours and 58 minutes and the shortest 29 days 6 hours and 34 minutes.

Simulated view of the moon’s phases. The period of time from new moon to new moon is known as the lunar month, lunation or synodic month. From the years 1760 to 2200, the longest lunar month spans 29 days 19 hours and 58 minutes (Dec. 9, 1787 to Jan. 8, 1778) while the shortest lasts for 29 days 6 hours and 34 minutes (June 12 to July 12, 1885).

The shortest lunar month this year happens in between the new moons of April 18 and May 18. This lunar month is only 29 days 9 hours and 16 minutes long, or 3 hours and 28 minutes shorter than the mean lunar month of 29 days 12 hours and 44 minutes.