NASA have recently released the largest picture ever taken, with a staggering 1.5 billion pixels. To get an idea of how massive the picture is, you'll need a 600 HD television screens to look at the whole image in its proper resolution. The image is a sweeping bird's-eye view of a portion of the Andromeda galaxy (M31), our closest galactic neighbor which is over 2 million light-years away.
[Image Source: NASA]
It was of course captured by NASA's Hubble Telescope. In a statement from the official press release:
"The Hubble Space Telescope is powerful enough to resolve individual stars in a 61,000-light-year-long stretch of the galaxy’s pancake-shaped disk. It's like photographing a beach and resolving individual grains of sand. And there are lots of stars in this sweeping view -- over 100 million, with some of them in thousands of star clusters seen embedded in the disk."
This YouTube fly-through video shows the detail of the picture captured by NASA's Hubble Space Telescope. The full image is 69,536 x 22,230 pixels, takes up 4.3 GB of disk space, captures over 100 million stars and travels more than 40,000 light years. Each of those white dots is a sun, much like the sun that powers all life on earth.
As the galaxy is our closest galactic neighbor, it is a much bigger target in the sky than the myriad galaxies Hubble routinely photographs that are billions of light-years away. This means that the Hubble survey is assembled together into a mosaic image using 7,398 exposures taken over 411 individual pointings.
The Panchromatic Hubble Andromeda Treasury (PHAT) program then takes the images and stitches them into a panoramic view. The Advanced Camera for Surveys and the Wide Field Camera 3 aboard Hubble captured images in near-ultraviolet, visible, and near-infrared wavelengths, with the image above showing a 48,000-light-year-long stretch of the galaxy in its natural visible-light color.