Like anyone else who’s ever looked up at the night sky in any but the smallest cities, I’ve seen light pollution first-hand. Like anyone else even marginally involved in amateur astronomy, I know about the fight against light pollution. And I know that, what with new LED lights and everything, it’s not going to be easy.

When, the other day, I was looking around for images demonstrating the effects of light pollution, it didn’t take me long to find some scary examples – the satellite images tracing human presence on Earth by its light pollution are rather unequivocal, and on Wikimedia Commons, there was an impressive image showing the same region of the night sky when viewed from a dark and from a lighter location:

The images were taken by Jeremy Stanley and are available via Wikimedia Commons under the CC BY 2.0 license. According to the author’s comment, he tried to match the two images’ sky brightness to his memory of how bright the sky appeared to his eyes.
What I didn’t find was an image showing a comparison of two images with the same specs (same camera and lens, same ISO, aperture and exposure time) under different viewing conditions. In the end, I found that I could produce such an example myself, using images I had taken during a trip to South Africa last spring.

via See Light Pollution in Action.

This series of images shows the asteroid P/2013 R3 breaking apart, as viewed by the NASA/ESA Hubble Space Telescope in 2013. This is the first time that such a body has been seen to undergo this kind of break-up. Credit: NASA, ESA, D. Jewitt (UCLA).

Back in 2010, astronomers discovered an asteroid that was breaking apart due to a head-on collision with another asteroid. But now they have seen an asteroid break apart – with no recent collision required.

Asteroid P/2013 R3 appears to be crumbling apart in space, and astronomers using the Hubble Space Telescope recently saw the asteroid breaking into as many as 10 smaller pieces. The best explanation for the break-up is the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect, a subtle effect from sunlight that can change the asteroid’s rotation rate and basically cause a rubbly-type asteroid to spin apart.

“This is a really bizarre thing to observe — we’ve never seen anything like it before,” said co-author Jessica Agarwal of the Max Planck Institute for Solar System Research, Germany. “The break-up could have many different causes, but the Hubble observations are detailed enough that we can actually pinpoint the process responsible.”

Astronomers first noticed this asteroid on September 15, 2013 and it appeared as a weird, fuzzy-looking object, as seen by the Catalina and Pan-STARRS sky-survey telescopes. A follow-up observation on Oct. 1 with the W.M. Keck telescope on Hawaii’s Mauna Kea revealed three co-moving bodies embedded in a dusty envelope that is nearly the diameter of Earth.

Then on October 29, 2013, astronomers used the Hubble Space Telescope to observe the object and saw there were actually 10 embedded objects, each with comet-like dust tails. The four largest rocky fragments are up to 200 meters/yards in radius, about twice the length of a football field.

The Hubble data showed that the fragments are drifting away from each other at a leisurely pace of 1.6 km/hr (one mile per hour), which would be slower than a strolling human.

“Seeing this rock fall apart before our eyes is pretty amazing,” said David Jewitt, from UCLA’s Department of Physics and Astronomy, who led the investigation.

via Hubble Telescope Watches Asteroid Disintegrate in Space.

Josh Worth’s HTML scale model of the Solar System

One of my favorite pet peeves is the inability of conventional models to accurately convey the gigantic scale of the Solar System. Most of us grew up with models of the planets made of wood or plastic or spray painted styrofoam balls impaled on bent wire hangers (don’t tell Mommy), or, more commonly, illustrations on posters and in textbooks. While these can be fun to look at and even show the correct relative sizes of the planets (although usually not as compared to the Sun) there’s one thing that they simply cannot relate to the viewer: space is really, really, really big.

Now there are some more human-scale models out there that do show how far the planets are from each other, but many of them require some walking, driving, or even flying to traverse their full distances. Alternatively, thanks to the magic of web pages which can be any size you like limited only by the imagination of the creator (and the patience of the viewer), accurate models can be easily presented showing the average (read: mind-blowingly enormous) distances between the planets… and no traveling or wire hangers required.

via If the Moon Were Only One Pixel: a Scale Model of the Solar System.