See a comparison of Hubble and Webb images

Why astronomers need so many powerful space telescopes is unclear. Surely a more powerful telescope is better than a less powerful one? Why are there so many different telescopes in orbit around the Earth or around the Sun?

The answer has to do with two main factors. One is the telescope’s field of view, which is how much of the sky it sees. Some telescopes are useful for viewing large areas of the sky in less detail, and to identify objects for research or to view the universe on a larger scale – such as the recently launched Euclid mission. Others, like the Hubble Space Telescope, see small areas of the sky in great detail, useful for studying specific objects.

Another important factor for space telescopes is the wavelength at which they operate. Both Hubble and the James Webb Space Telescope are used to study objects such as galaxies, but they do so at different wavelengths. Hubble operates primarily in visible light wavelengths similar to the human eye, while WEB operates in the infrared. That means they can see different aspects of the same object.

To demonstrate how that works in practice, a new comparison shows the galaxy NCG 3256, the same target seen by both Webb and Hubble.

This web image shows the trends in the dust and gas that make up the galaxy’s arms. When new young stars are born from dust and gas, they emit radiation that hits the surrounding dust, causing the dust to glow in the infrared. Young stars also shine brightly in the infrared wavelengths, with bright regions marking hot spots of star formation.

The Hubble image, which shows the same galaxy but at a different wavelength, was originally taken in 2018. While the Webb’s infrared view allows it to see through dust clouds, Hubble produces dark filaments in the visible light range operating in dust. Out of the light. The galaxy is much brighter in infrared than light wavelengths, but in this range, you can clearly see that the galaxy actually has two centers, or nuclei, the result of the merging of two galaxies.

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