Astronomers have finalized an extensive study of the Andromeda Galaxy using the Hubble Space Telescope, resulting in a unique 417-megapixel panorama. This project spanned over a decade and involved more than 600 images, culminating in a mosaic measuring 42208 × 9870 pixels—the largest image ever captured by Hubble.
The panorama showcases over 200 million stars, a mere fraction of the trillion stars within the galaxy. The mosaic's details, comprising 2.5 billion pixels, enable scientists to delve deeper into Andromeda's history, particularly its mergers with other galaxies.
As the closest neighbor to the Milky Way, Andromeda has long captivated astronomers. A century ago, Edwin Hubble established that this object lies beyond the Milky Way, fundamentally altering humanity's perception of the universe. Previously, it was thought that the Milky Way encompassed the entirety of the cosmos.
Andromeda is crucial for understanding the structure and evolution of our galaxy. The images obtained through Hubble provide a unique opportunity to study the galaxy's details as a whole, which is unattainable with other large galaxies.
Lead researcher Ben Williams from the University of Washington emphasizes that Hubble continues to provide extraordinarily detailed data that is vital for science. Even with the advent of the James Webb Space Telescope, Hubble remains an indispensable tool for astronomy.
Capturing images of Andromeda posed significant challenges due to its vast size and relative proximity—2.5 million light-years away. NASA refers to this mission as a 'Herculean task.' The creation of the mosaic took over 10 years of work.
The project began with the Panchromatic Hubble Andromeda Treasury (PHAT) program, which explored the northern part of the galaxy across ultraviolet, visible, and infrared spectra. Subsequently, the Panchromatic Hubble Andromeda Southern Treasury (PHAST) program supplemented the research of the southern part, adding data on approximately 100 million stars. Together, these programs covered the entire disk of Andromeda visible from Earth at a tilt of 77 degrees.
During the study, it was discovered that Andromeda underwent a merger with another galaxy, leading to active star formation, which later ceased.
The upcoming Nancy Grace Roman Space Telescope is expected to open new horizons in the study of the universe. Equipped with wide-angle optics, it will capture the equivalent of 100 high-resolution Hubble images in a single exposure. Data from Nancy Grace, combined with information from Hubble and James Webb telescopes, will facilitate deeper exploration of the Andromeda Galaxy and the universe at large.