La imagen del telescopio espacial Hubble muestra NGC4826, una galaxia espiral ubicada a 17 millones de años luz de distancia en la constelación Coma Berenice (Pelo de Berenice). Esta galaxia a menudo se conoce como la galaxia del «ojo morado» o del «mal de ojo» debido a la banda de polvo oscuro que barre un lado de su núcleo brillante. Crédito: ESA/Hubble y NASA, J. Lee y el equipo PHANGS-HST, Agradecimientos: Judy Schmidt
Una galaxia es una colección de estrellas, polvo, gas y materia oscura unidos por la gravedad. Las galaxias contienen desde unos pocos cientos de millones hasta cien billones de estrellas.
Las galaxias son grupos de estrellasY polvo, gas y materia oscura, que están conectados entre sí por la fuerza gravitacional generada por su masa. Una pequeña galaxia enana contiene unos pocos millones de estrellas, mientras que las galaxias más grandes conocidas pueden contener hasta cien billones de estrellas.
Hay muchas formas diferentes de galaxias, incluyendo galaxias elípticas y galaxias espirales. Muchas galaxias, incluyendo[{» attribute=»»>Milky Way, have supermassive black holes at their centers. If the black hole is active, then the galaxy’s active core is classified as an active galactic nucleus (AGN). Galaxies are highly dynamic, evolving considerably throughout their lifetimes and interacting with one another.
As they are so large and bright, it is possible to study galaxies that are extremely far away — galaxies more than 13 billion light-years distant from Earth have been observed. The speed of light is finite, meaning that, for example, if a galaxy 13 billion light-years away is observed, it is seen how it was 13 billion years ago. This makes the study of galaxies a fascinating opportunity to study ‘fossils’ from the history of the Universe, thus providing clues to how the Universe has evolved over time.
Una galaxia es un grupo de estrellas, polvo, gas y materia oscura unidos por la gravedad. Las galaxias contienen desde unos pocos cientos de millones hasta cien billones de estrellas. Crédito: ESA/Hubble, ESA,[{» attribute=»»>NASA & L. Calçada
One of the main scientific justifications for building Hubble was to measure the size and age of the Universe and test theories about its origin. Using Hubble, astronomers were able to study young galaxies in the early Universe and the most distant primeval galaxies.
Hubble has imaged and studied galaxies of all kinds, including elliptical, spiral, and irregular galaxies, and of various different sizes, including dwarf galaxies. In this image of Messier 60 and NGC 4647, Hubble has imaged both an elliptical and a spiral galaxy, allowing for a clear comparison of the two galaxy types. Elliptical galaxies, the yellow fuzzy objects seen in the image, are most often found close to the centers of galaxy clusters, while spirals, the bluish patches, are usually found further out and more isolated.
Galaxy. Credit: ESA/Hubble & NASA, J. Lee and the PHANGS-HST Team
Hubble has also observed beautiful, rare galaxy merging events, during which galaxies undergo dramatic changes in their appearance and in their stellar content. These systems are excellent laboratories in which to trace the formation of star clusters under extreme physical conditions.
Some of Hubble’s most popular images have been of galaxies. You can explore the vast ESA/Hubble archive of more than 1500 galaxy images here.
