Science Pics of the Week: It's true! A blue sky on Mars!

Saturday, May 9, 2015, 1:32 PM - A blue-tinged sunset on Mars, Hubble discovers that Andromeda is bigger than we thought, and the latest in a series of incredible explosions on the Sun.

Blue Sky On Mars

Seeing sunset pictures from the Mars Curiosity rover isn't new. The view from its cameras is always amazing.

However, on April 15, it got better.

Credit: NASA/JPL-Caltech/MSSS

According to NASA's Jet Propulsion Laboratory:

This was the first sunset observed in color by Curiosity. The image comes from the left-eye camera of the rover's Mast Camera (Mastcam). The color has been calibrated and white-balanced to remove camera artifacts. Mastcam sees color very similarly to what human eyes see, although it is actually a little less sensitive to blue than people are.
Dust in the Martian atmosphere has fine particles that permit blue light to penetrate the atmosphere more efficiently than longer-wavelength colors. That causes the blue colors in the mixed light coming from the sun to stay closer to sun's part of the sky, compared to the wider scattering of yellow and red colors. The effect is most pronounced near sunset, when light from the sun passes through a longer path in the atmosphere than it does at mid-day.

Maybe Douglas Quaid wasn't dreaming after all.

Andromeda Gets MUCH Bigger

Our neighbour galaxy, Andromeda, is considered to be about twice the size of our home galaxy, the Milky Way. While our estimates of the size of our home galaxy might need to be revised based on some recent findings, a new look using the Hubble Space Telescope shows that, due to an immense halo of gas surrounding it, Andromeda is much, MUCH bigger than it looks like at first glance.

Credit: NASA, ESA, and A. Feild (STScI)

"Halos are the gaseous atmospheres of galaxies. The properties of these gaseous halos control the rate at which stars form in galaxies according to models of galaxy formation," explained the lead investigator, Nicolas Lehner of the University of Notre Dame, Indiana. The gargantuan halo is estimated to contain half the mass of the stars in the Andromeda galaxy itself, in the form of a hot, diffuse gas. If it could be viewed with the naked eye, the halo would be 100 times the diameter of the full Moon in the sky. This is equivalent to the patch of sky covered by two basketballs held at arm's length.

If we thought we were going to match Andromeda due to the new 'corrugated' view of our galaxy, we might have to think again. On the other hand, our Milky Way may also have one of these immense galactic atmospheres, which is just invisible to us looking from the inside out.

Active Region on the Sun is REALLY Active

The eastern limb of the Sun has been a pretty active place over the past week. A massive dark filament erupted, then it blasted out one of the most powerful solar flares (X2-class) of the year so far, and now, early on Saturday morning, it unleashed another filament eruption, which was captured by NASA's Solar Dynamics Observatory (SDO).

If the view looks a little strange, given that our Sun is a yellow star, it's because this is a combination of three different filtered looks that SDO captured at the time. The Purple (211 Angstrom), Bronze (193 Angstrom) and Gold (171 Angstrom) filters have been used to form the Red, Green and Blue of your standard colour image, and the result looks like this. Since these three filters highlight different parts of the Sun's corona, it provides an exceptional view of this complex region of the Sun's atmosphere, showing off filaments, loops and mass ejections like the one that was unleashed Saturday morning.

Sources: NASA JPL | NASA/ESA/Hubble | NASA SDO | SpaceWeather.com