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Jan Oort. Copyright Leiden Observatory. Used with permission.

This date in science: Jan Oort’s birthday

Visualize a vast reservoir of icy comets on the outskirts of our solar system. That’s what Jan Oort did in 1950, and why the Oort Cloud bears his name.


What makes a red rainbow?

Red rainbows happen when the sun is on the horizon. They’re created in much the same process that causes a sunset or sunrise to look red.

Discovery image for first-ever known moon orbiting the remote dwarf planet Makemake.

Dwarf planet Makemake has a moon

This Hubble Space Telescope image reveals the first moon ever discovered around little Makemake, in the outermost region of our solar system.

Venus Express aerobraking. Image credit: ESA - C. Carreau

What Venus Express learned by aerobraking

Results from the Venus Express spacecraft, obtained when – in the craft’s final months – it surfed the dense atmosphere of Venus.

Moon rocks collected b Apollo astronauts have been found to contain an element created only by supernovae. Here, Apollo 12-astronaut Alan Bean takes a sample of the lunar surface. Photo via NASA.

Moon rocks reveal nearby supernova

Iron-60 found in moon rocks supports an earlier finding that – 2 million years ago – a supernova exploded only 300 light-years away.

Crab Nebula

Crab Nebula was an exploding star

The Crab Nebula, located some 6,500 light years from Earth, marks the remains of a massive star observed to explode as a supernova in AD 1054.

Image via Neha Golwala

Photos from friends: Favorite images of Earth

In celebration of Earth Day 2016, we’ve brought together some of our favorite images of Earth by the EarthSky community. Thank you all!

Image via New Scientist

10 surprises about our solar system

A collection of 10 unexpected and intriguing facts about our solar system – our sun and its family of planets – you probably did not know!


Eastern monarch butterflies at risk of extinction, scientists say

Populations of the charismatic orange and black monarch butterfly have plummeted. Will they be extinct in 20 years?

This green moon photo was created via photo processing, and is via Wikimedia Commons.

Green moon on April 20, 2016? Not true

No, there won’t be a green moon on April 20, 2016 … or on May 29. Some possible origins of this latest urban legend.