Would it be surprising to find a rocky planet that dates back to the very early Universe? It should be. The early Universe lacked the heavier elements necessary to form rocky planets.
But astronomers have found one, right here in the Milky Way.
Continue reading “One of the Oldest Stars in the Galaxy has a Planet. Rocky Planets Were Forming at Nearly the Beginning of the Universe”
Spiral galaxies are one of the most commonly known types of galaxy. Most people think of them as large round disks, and know that our Milky Way is counted among their number. What most people don’t realize is that many spiral galaxies have a type of warping effect that, when you look at them edge on, can make it seem like they are forming a wave. Now scientists, led by Xinlun Chen at the University of Virginia, have studied millions of stars in the Milky Way and begun to develop a picture of a “wave” passing through our own galaxy.
Continue reading “You Can Actually See the Milky Way’s Wave When You Map Its Stars”
Within our galaxy, there are thousands of stars that orbit the center of the Milky Way at high velocities. On occasion, some of them pick up so much speed that they break free of our galaxy and become intergalactic objects. Because of the extreme dynamical and astrophysical processes involved, astronomers are most interested in studying these stars – especially those that are able to achieve escape velocity and leave our galaxy.
However, an international team of astronomers led from the National Astronomical Observatories of China (NAOC) recently announced the discovery of 591 high-velocity stars. Based on data provided by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and the ESA’s Gaia Observatory, they indicated that 43 of these stars are fast enough to escape the Milky Way someday.
Continue reading “Astronomers Discover Hundreds of High-Velocity Stars, Many on Their Way Out of the Milky Way”
Where are we? Cosmically, we’re in our home galaxy, typically known as the Milky Way. The center of our galaxy is marked by a supermassive black hole, which the Sun orbits at a distance of about 30,000 light-years. The official distance, set by the International Astronomical Union in 1985, is 27,700 light-years. But a new study as confirmed we are actually a bit closer to the black hole.
Continue reading “A new measurement puts the Sun 2,000 light-years closer to the center of the Milky Way”
Ten billion years ago the young Milky Way survived a titanic merger with a neighboring galaxy, eventually consuming the whole thing. Now, remnants of that fossil galaxy still swim in our galaxy’s core – and astronomers have discovered that almost a third of the Milky Way’s current population came from that dismantled rival.
Continue reading “A third of the stars in the Milky Way came from a single merger 10 billion years ago”
One of the ways we categorize stars is by their metallicity. That is the fraction of heavier elements a star has compared to hydrogen and helium. It’s a useful metric because the metallicity of a star is a good measure of its age.
Continue reading “Some of the Milky Way’s oldest stars aren’t where they’re expected to be”
Like other spiral galaxies, the Milky Way has a bulging sphere of stars in its center. It’s called “The Bulge,” and it’s roughly 10,000 light-years in radius. Astronomers have debated the bulge’s origins, with some research showing that multiple episodes of star formation created it.
But a new survey with the NOIRLab’s Dark Energy Camera suggests that one single epic burst of star formation created the bulge over 10 billion years ago.
Continue reading “The Spherical Structure at the Core of the Milky Way Formed in a Single Burst of Star Formation”
A team of researchers has discovered a complex network of filamentary structures in the Milky Way. The structures are made of atomic hydrogen gas. And we all know that stars are made mostly of hydrogen gas.
Not only is all that hydrogen potential future star-stuff, the team found that its filamentary structure is also a historical imprint of some of the goings-on in the Milky Way.
Continue reading “Astronomers Map Out the Raw Material for New Star Formation in the Milky Way”
In 2005 astronomers found a dense grouping of stars in the Virgo constellation. It looked like a star cluster, except further surveys showed that some of the stars are moving towards us, and some are moving away. That finding was unexpected and suggested the Stream was no simple star cluster.
A 2019 study showed that the grouping of stars is no star cluster at all; instead, it’s the hollowed-out shell of a dwarf spheroidal galaxy that merged with the Milky Way. It’s called the Virgo Overdensity (VOD) or the Virgo Stellar Stream.
A new study involving some of the same researchers shows how and when the merger occurred and identifies other shells from the same merger.
Continue reading “Astronomers Find the Hollowed-Out Shell of a Dwarf Galaxy that Collided With the Milky Way Billions of Years Ago”
The heart of the Milky Way can be a mysterious place. A gigantic black hole resides there, and it’s surrounded by a retinue of stars that astronomers call a Nuclear Star Cluster (NSC). The NSC is one of the densest populations of stars in the Universe. There are about 20 million stars in the innermost 26 light years of the galaxy.
New research shows that about 7% of the stars in the NSC came from a single source: a globular cluster of stars that fell into the Milky Way between 3 and 5 billion years ago.
Continue reading “7% of the Stars in the Milky Way’s Center Came From a Single Globular Cluster That Got Too Close and Was Broken Up”