isuniverse

A sunset in color…

Take a good look at this image, let it soak in. This is more than just a simple sunset, this is what a sunset looks like on Mars. Yep, on Mars. Slightly different than the reddish sunsets we are used to on Earth.

NASA’s Curiosity Mars rover recorded this view of the sun setting at Gale Crater on the April 15, which marked the 956th Martian day, or sol. This series of images, composed as an animation, is the first time Curiosity observed a Martian sunset in color. The images were captured by Curiosity’s Mastcam, which “sees” color very similar to the way we do, although it is slightly less sensitive to blue light.

So why does the sunset appear blue? The Martian atmosphere contains very fine particles that allow blue light to penetrate the atmosphere better than longer wavelengths (like red). As a result blue colors tend to stay in the sky and red/yellow scatter more easily. This effect is more easily seen at sunset when light from the sun passes through a longer path in the atmosphere than it does at mid-day.

“The colors come from the fact that the very fine dust is the right size so that blue light penetrates the atmosphere slightly more efficiently,” said Mark Lemmon of Texas A&M University, College Station, the Curiosity science-team member who planned the observations. “When the blue light scatters off the dust, it stays closer to the direction of the sun than light of other colors does. The rest of the sky is yellow to orange, as yellow and red light scatter all over the sky instead of being absorbed or staying close to the sun.”

Sunsets tend to feature more dramatic colors here on Earth; however, Martian sunsets tend to showcase mainly blue light, with more reddish/rust colors during the day.This sunset is more than a pretty picture, as sunset observations will tell scientists more about the vertical distribution of dust in Mars’ atmosphere.

-ALT

Image & Source Credit: NASA/JPL-Caltech

Pluto in False Color

Pluto is shown in false colors to help scientists differentiate between regions of different surface compositions and textures. The heart-shaped region on Pluto’s surface (seen in the photo) is unofficially named “Tombaugh Regio” in honor of the man who discovered the dwarf planet, Clyde Tombaugh. The heart of Tombaugh Regio is called “Sputnik Planum” as an homage to the first satellite to orbit the Earth – Sputnik. Within this heart of the heart, scientists have detected signs that the region contains different ices and may have even been geologically active in recent history.

In order to create this false-color global view of Pluto, four images from New Horizons’ Long Range Reconnaissance Imager (LORRI) were combined with color data from the Ralph instrument. The images, taken when the spacecraft was 280,000 miles (450,000 kilometers) away, show features as small as 1.4 miles (2.2 kilometers).

Pluto continues to amaze. This is just the tip of the iceberg; we have 16 months of data still to come.

Image & Source Credit: NASA/JHUAPL/SwRI

A night at the meteors

This image is a compilation of several hours of astrophotography last Wednesday during the Perseid Meteor Shower. It was submitted to us by contributor Daniel Gaussen.

It was taken at night in the Peak District of the United Kingdom using a Canon 600d with a Samyang 16mm F2.0 manual lens. To produce this image, he did a series of 15 second exposure time lapse images with 2second gaps in-between covering a period of about 2.5 hours. He then overlaid the objects that had moved or streaked across the sky on a single background frame to avoid star trails and produce a fixed image.

Many of the streaks are Perseid meteors – you can definitely get the impression of them spreading out from the center of the sky. A couple of the streaks are other things – he caught a few satellites in the shot – those satellites move slower than the meteors and thus the two second gaps cause breaks in the trails of satellites that don’t appear in the meteor trails. Also take note of how the camera captures the color change on the trails of the meteors.

Thanks for the submission Daniel

-JBB

Image credit