Most galaxies lie in clusters containing from a few to thousands of other galaxies. Our Milky Way, for example, belongs to the Local Group cluster of about fifty galaxies whose other lar...

Stellar variability has long offered insights into stars' physical properties. The star Mira (Omicron Ceti), for example, was so-named in 1596 by Dutch astronomers who were amazed by its...

The young star Eta Carinae shines prominently in the skies of the southern hemisphere. Although located relatively far away from Earth (about seven thousand light-years away, as compared...

One year ago this week astronomers discovered an unusual object moving through space not too far from the Earth's orbit. In just a few days they realized it could not be a normal asteroid...

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Most galaxies host a supermassive black hole (SMBH) at their nucleus (a supermassive black hole is one whose mass exceeds a million solar-masses.) A key unresolved issue in galaxy format...

Sagittarius A* (Sgr A*), the supermassive black hole at the center of our Milky Way Galaxy, is 100 times closer to us than any other SMBH and therefore a prime candidate for studies of ho...

Ultra-faint, dwarf galaxies are the smallest, most dark matter dominated, and least chemically enriched stellar systems in the universe and are important targets for understanding dark ma...

Cambridge, MA - NASA has awarded a contract extension to the Smithsonian Astrophysical Observatory (SAO) in Cambridge, Massachusetts, to continue operations and science support for the...

Just over a month into its mission, Parker Solar Probe has returned first-light data from each of its four instrument suites. These early observations – while not yet examples of the key ...