All that
95. glitters
This striking Hubble Space Telescope image shows a glittering bauble named
Messier 92. Located in the northern constellation of Hercules, this globular cluster
— a ball of stars that orbits a galactic core like a satellite — was first discovered by
astronomer Johann Elert Bode in 1777.
Messier 92 is one of the brightest globular clusters in the Milky Way, and is visible to
the naked eye under good observing conditions. It is very tightly packed with stars,
containing some 330 000 stars in total. As is characteristic of globular clusters, the
predominant elements within Messier 92 are hydrogen and helium, with only traces
of others. It is actually what is known as an Oosterhoff type II (OoII) globular cluster,
meaning that it belongs to a group of metal-poor clusters — to astronomers,
metals are all elements heavier than hydrogen and helium.
By exploring the composition of globulars like Messier 92, astronomers can figure
out how old these clusters are. As well as being bright, Messier 92 is also old, being
one of the oldest star clusters in the Milky Way, with an age almost the same as the
age of the Universe.
Credit: ESA/Hubble & NASA
“It is hard to say what Hubble’s lasting scientific
legacy will be, as I would imagine there are
fundamental discoveries across the entire range
of sub-fields within astronomy and physics.
“With regards to Hubble’s legacy amongst society,
the story of Hubble is a human one which can
touch all of us. Hubble overcame adversity
early on, from problems with the mirror optics to
gyroscope and instrument failures.
“Despite all of these challenges, Hubble has
proceeded to revolutionize our understanding
of the cosmos. NASA believes that Hubble can
get to 2020 and beyond, a lifetime that was likely
inconceivable at launch.
“To me, Hubble’s story tells us that with
perseverance, we can far exceed our own
expectations.”
— Dr. Katherine E. Whitaker
NASA Postdoctoral Program Fellow
Goddard Space Flight Center
Greenbelt, Maryland