It seems unclear why astronomers need so many powerful space telescopes. Is it certain that a more powerful telescope is better than a less powerful one? So why are there different telescopes in orbit, both around the Earth and around the Sun?
The answer has to do with two main factors. One of these is the telescope’s field of view, which means how far in the sky it sees. Some telescopes are useful for viewing large areas of the sky with less detail, serving as survey telescopes for pinpointing objects for further investigation or for viewing the universe on a large scale—such as the recently launched Euclid mission. Others, such as the Hubble Space Telescope, see small regions of the sky in great detail, which is useful for studying specific objects.
Another important factor for space telescopes is the wavelength at which they operate. Both the Hubble and James Webb Space Telescopes are used to study objects like galaxies, but they do so at different wavelengths. Hubble operates primarily in the visible wavelengths of light, such as the human eye, while Webb operates in the infrared. This means that they can see different sides of the same thing.
To illustrate how this works in practice, the new comparison shows the same target, galaxy NCG 3256, as seen by Webb and Hubble.
The odd galaxy NGC 3256 dominates this image from the NASA/ESA/CSA James Webb Space Telescope. Located about 120 million light years away in the constellation Phella, this galaxy the size of the Milky Way is home to the Hydra-Centaurus Supercluster. ESA/Webb, NASA & CSA, L. Armus, A. Evans
This web image shows the tendrils of dust and gas that make up the arms of this galaxy. When young stars are born from dust and gas, they release radiation that hits nearby dust grains, causing the dust to glow in the infrared. Young stars also shine brightly in infrared wavelengths, with the brightest regions indicating hotbeds of star formation.
The odd galaxy NGC 3256 takes center stage in this image from the NASA/ESA Hubble Space Telescope. This distorted galaxy is the remnants of a head-on collision between two spiral galaxies that most likely occurred 500 million years ago, and is filled with clumps of young stars formed by the collision of gas and dust from the two galaxies. European Space Agency/Hubble, NASA
The Hubble image, showing the same galaxy but seen at a different wavelength, was originally taken in 2018. While Webb’s infrared vision allows seeing through a cloud of dust, in the visible light range that Hubble works in dust creating dark filaments that block light. Galaxies are much brighter in the infrared than in visible wavelengths, but in this range you can see more clearly that the galaxy actually has two centres, or cores, the result of two galaxies merging together.
Editor’s recommendation
2023-07-09 11:22:54
#comparison #images #Hubble #Webb
