English: Despite the advances made in past decades, the process of galaxy formation remains an open question in astronomy. Various theories have been suggested, but since galaxies come in all shapes and sizes — including elliptical, spiral, and irregular — no single theory has so far been able to satisfactorily explain the origins of all the galaxies we see throughout the Universe.
To determine which formation model is correct (if any), astronomers hunt for the telltale signs of various physical processes. One example of this is galactic coronas, which are huge, invisible regions of hot gas that surround a galaxy’s visible bulk, forming a spheroidal shape. They are so hot that they can be detected by their X-ray emission, far beyond the optical radius of the galaxy. Because they are so wispy, these coronas are extremely difficult to detect. In 2013, astronomers highlighted NGC 6753, imaged here by the NASA/ESA Hubble Space Telescope, as one of only two known spiral galaxies that were both massive enough and close enough to permit detailed observations of their coronas. Of course, NGC 6753 is only close in astronomical terms — the galaxy is nearly 150 million light-years from Earth.
NGC 6753 is a whirl of colour in this image — the bursts of blue throughout the spiral arms are regions filled with young stars glowing brightly in ultraviolet light, while redder areas are filled with older stars emitting in the cooler near-infrared.
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να μοιραστείτε – να αντιγράψετε, διανέμετε και να μεταδώσετε το έργο
να διασκευάσετε – να τροποποιήσετε το έργο
Υπό τις ακόλουθες προϋποθέσεις:
αναφορά προέλευσης – Θα πρέπει να κάνετε κατάλληλη αναφορά, να παρέχετε σύνδεσμο για την άδεια και να επισημάνετε εάν έγιναν αλλαγές. Μπορείτε να το κάνετε με οποιοδήποτε αιτιολογήσιμο λόγο, χωρίς όμως να εννοείται με οποιονδήποτε τρόπο ότι εγκρίνουν εσάς ή τη χρήση του έργου από εσάς.
https://creativecommons.org/licenses/by/4.0CC BY 4.0 Creative Commons Attribution 4.0 truetrue
Αυτό το αρχείο περιέχει πρόσθετες πληροφορίες, πιθανόν από την ψηφιακή φωτογραφική μηχανή ή το scanner που χρησιμοποιήθηκε για την δημιουργία ή την ψηφιοποίησή της. Αν το αρχείο έχει τροποποιηθεί από την αρχική του κατάσταση, ορισμένες λεπτομέρειες πιθανόν να μην αντιστοιχούν πλήρως στην τροποποιημένη εικόνα.
Αναφορά/Πάροχος
ESA/Hubble & NASAAcknowledgement: Judy Schmidt
Πηγή
ESA/Hubble
Συνοπτικός τίτλος
More than meets the eye
Τίτλος εικόνας
Despite the advances made in past decades, the process of galaxy formation remains an open question in astronomy. Various theories have been suggested, but since galaxies come in all shapes and sizes — including elliptical, spiral, and irregular — no single theory has so far been able to satisfactorily explain the origins of all the galaxies we see throughout the Universe. To determine which formation model is correct (if any), astronomers hunt for the telltale signs of various physical processes. One example of this is galactic coronas, which are huge, invisible regions of hot gas that surround a galaxy’s visible bulk, forming a spheroidal shape. They are so hot that they can be detected by their X-ray emission, far beyond the optical radius of the galaxy. Because they are so wispy, these coronas are extremely difficult to detect. In 2013, astronomers highlighted NGC 6753, imaged here by the NASA/ESA Hubble Space Telescope, as one of only two known spiral galaxies that were both massive enough and close enough to permit detailed observations of their coronas. Of course, NGC 6753 is only close in astronomical terms — the galaxy is nearly 150 million light-years from Earth. NGC 6753 is a whirl of colour in this image — the bursts of blue throughout the spiral arms are regions filled with young stars glowing brightly in ultraviolet light, while redder areas are filled with older stars emitting in the cooler near-infrared.
Όροι χρήσης
Creative Commons Attribution 4.0 International License
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