Multispectral imaging

I've hesitated to call this a new window but on reflection I think it deserves the accolade. Multispectral imaging involves creating single images derived from observations in different parts of the electromagnetic spectrum to reveal what one contribution can't show. We'll see a lot more multispectral images in the 2020s and beyond. The accompanying image released by ESA in 2019 is a nice example. Most of the radiation comes from the galaxy NGC 300, about 6 million light years away.

The blue are sources detected at X-ray wavelengths by ESA's XMM-Newton space observatory. They represent a variety of very energetic sources: stars near the end of their life that are nearly supernovae, supernova remnants, neutron stars, black holes. The large blue blob partly showing top left is from exceedingly hot gas in a cluster of galaxies some 2 billion light years away.

The green shows 'normal' stars in the galaxy, observed in visible light. The red shows cool gas observed in the infrared by NASA's Spitzer space telescope. This is where future stars will be born.

Taken together, the image gives an impression of the old, the current and the new in terms of stellar evolution. Not quite a timeline but hinting at one.

Multispectral image posted by ESA showing stellar evolution around the 'nearby' galaxy NGC 300.