It might be old, bits of it might go offline with increasing regularity, but Hubble still does cutting edge science as this enormous portrait of Andromeda shows.
Pop quiz: how old is the Hubble Space Telescope? I asked a dozen people this and everyone was at least a few years out, even though most of them have at least a passing interest in science and tech in general. It is going to be an astonishing 35 years old this year, and is still doing important science; a record that its developers and builders can a) only have hoped for and b) be very proud of.
Its latest achievement is to have contributed 600 separate photographs to this astonishing photomosaic of Andromeda. It was a century ago that Edwin Hubble himself established the fact that the faint cigar-shaped object roughly the apparent angular diameter of our Moon, Andromeda (or Messier 31 to give it its proper name), was actually outside of our own Milky Way galaxy. Before then, the orthodox cosmological view was that the Milky Way encompassed the entire known universe, and that Andromeda had to be part of it as a result. Hubble's estimate that M31 was 2.5 million lightyears away turned all that on its head in an impressive manner.
The mosaic was produced from two separate Hubble programs. In total, it required over 1000 Hubble orbits spanning more than a decade, and the largest one you can download is a massive 42,208 x 9870. To save you reaching for the calculator, that is 416,591,960; 417 megapixels if you round it up. That is still dwarfed by the original though, which contains 2.5 billion pixels or 2500 megapixels.
It captures the glow of 200 million stars which, while impressive, is still only a fraction of Andromeda’s total population.
The first program, the Panchromatic Hubble Andromeda Treasury (PHAT) program about a decade ago, obtained images at near-ultraviolet, visible, and near-infrared wavelengths using the Advanced Camera for Surveys and the Wide Field Camera 3 aboard Hubble to photograph the northern half of Andromeda. This program was followed up by the Panchromatic Hubble Andromeda Southern Treasury (PHAST), recently published in The Astrophysical Journal and led by Zhuo Chen at the University of Washington, which added images of approximately 100 million stars in the southern half of Andromeda.
Hubble’s new findings will support future observations by NASA’s James Webb Space Telescope and the upcoming Nancy Grace Roman Space Telescope. We've written about Roman (below) before; essentially this is a wide-angle version of Hubble (with the same sized mirror), and will capture the equivalent of at least 100 high-resolution Hubble images in a single exposure. Less orbits, more science; we look forward to that.
h/t to Petapixel