Saturday, 26 December 2020

Stars, stars everywhere

Again, it’s Hubble Space Telescope that comes in help to satisfy our desire of wonder, giving us the exquisite gift of this image from the globular cluster named Messier 107.

Globular cluster Messier 107. Credit: ESA/NASA

What can I say? It resembles a crowded stadium before a show, when we was still able to gather together to take part to an event (but times will return, I’m pretty sure, in which this will be possible again).

Messier 107 is one in about one hundred and fifty globular clusters present in our Milky Way. Each of them contains hundred of thousands of stars, sometimes even millions of them. They are very old: in fact, they are listed among the oldest objects in the whole Universe.

I remember a time (in the previous century) in which astronomy was facing a real crisis, exactly because of these clusters: from accurate evaluations, their stars shown an age greater that the estimated age of the universe. Rather embarrassing, I should say! Now we has reached a nice convergence between star ages and cosmological age of the universe, and the problem can be considered solved.

Anyway, as astronomer I can say we lived a very interesting time, since researches was boosted by this problematic and by the desire to find a solution. As a matter of fact, efforts were made till ages from stellar evolution was deeply revised (clusters lost several billion of years, in this process), but also the cosmological framework was updated (as a consequence the universe as a whole gained some billion years in respect to previous estimates). Finally, as you probably know, an age of around 13.8 billion years seems to fit well both for stars that for universe itself.

Nice lesson. Science always goes forward attempting to solve problems. Each problem treasure a possibility, to learn even more, to gain new views, to revise settled believes. When science does not face problems, it’s not always a good sign: we are missing the opportunity to learn something, probably.

Granted, in real life is not always easy, to view possibilities inside problems. But who knows, maybe science can teach us something, in this case…

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