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Posted on May 16, 2021
Telescopes are the most recognizable tool in the astronomer’s toolkit, but equally important are the tools for recording astronomical data. In the 19th century, they included glass photographic plates, which captured snapshots of the night sky through the telescope, and notebooks for recording observations and measurements from the plates.
The 24-inch Bruce Doublet telescope installed in Arequipa, Peru. (Courtesy of Harvard College Observatory)
Left: Glass plate photograph taken in Arequipa in 1925. (Courtesy of Harvard). Right: Cover of Annie Jump Cannon’s notebook featuring ‘Observations in Arequipa.’ (Courtesy of Harvard (Image ID: phaedra2228))
Beginning in 1885, the Harvard College Observatory (now part of the Harvard-Smithsonian Center for Astrophysics) began an ambitious project to survey the entire night sky. Astronomers at Harvard’s central observatory in Cambridge, Massachusetts, and its new observatory in Arequipa,
Globular clusters are the oldest visible objects in the Universe – each contains hundreds of thousands to occasionally over one million stars, all born at essentially the same time. They are densely packed into a spherical volume with a diameter over a thousand times smaller than the diameter of the Milky Way Galaxy. Globular clusters are thought to have formed soon after the Universe began nearly 13.8 billion years ago, at the same time as, or perhaps even before, the first galaxies formed.
Harbor Oldest Stars in the Universe
Some of the oldest stars in the universe are found in ancient globular clusters that orbit around the halo of our home galaxy. The Milky Way is circled by at least 150 globular clusters, each harboring hundreds of thousands, and sometimes millions of stars. Globular clusters formed very early in the vast halo surrounding the embryonic Milky Way before it flattened to form a spiral disk.
Hundreds of bits of rocket, space stations and satellites have returned to Earth since the 1960s. They are often dumped at sea. How sustainable is that?