milky way Archives

January 29, 2024January 29, 2024 by Mark Thompson

There’s Less Dark Matter at the Core of the Milky Way

A study by MIT physicists suggest the Milky Way’s gravitational core may be lighter in mass, and contain less dark matter, than previously thought. Credits:Credit: ESA/Gaia/DPAC, Edited by MIT News

Science really does keep you on your toes. First there was matter and then there were galaxies. Then those galaxies had more stuff in the middle so stars further out were expected to move slowly, then there was dark matter as they actually seemed to move faster but now they seem to be moving slower in our Galaxy so perhaps there is less dark matter than we thought after all!

January 17, 2024January 17, 2024 by Brian Koberlein

Astronomers Have Mapped the Milky Way's Magnetic Fields in 3D

Magnetic fields mapped within the Whirlpool Galaxy. Credit: NASA, SOFIA science team, ESA, STScI

Our galaxy is filled with magnetic fields. They come not just from stars and planets, but from dusty stellar nurseries and the diffuse hydrogen gas of interstellar space. We’ve long known of this galactic magnetic field, but mapping it in detail has posed a challenge. Now a new study gives us a detailed 3-dimensional map of these fields, with a few surprises.

November 22, 2023November 22, 2023 by Evan Gough

Webb’s Infrared Eye Reveals the Heart of the Milky Way

The full view of the NASA/ESA/CSA James Webb Space Telescope’s NIRCam (Near-Infrared Camera) instrument reveals a 50 light-years-wide portion of the Milky Way’s dense centre. An estimated 500,000 stars shine in this image of the Sagittarius C (Sgr C) region, along with some as-yet unidentified features. Image Credit: NASA, ESA, CSA, STScI, S. Crowe (UVA)

The JWST is taking a break from studying the distant Universe and has trained its infrared eye on the heart of the Milky Way. The world’s most powerful space telescope has uncovered some surprises and generated some stunning images of the Milky Way’s galactic center (GC.) It’s focused on an enormous star-forming region called Sagittarius C (Sgr C).

November 20, 2023November 20, 2023 by Nancy Atkinson

Gaze Into the Heart of the Milky Way in This Latest JWST Image

James Webb Space Telescope’s NIRCam (Near-Infrared Camera) instrument reveals a 50 light-years-wide portion of the Milky Way’s dense center. An estimated 500,000 stars shine in this image of the Sagittarius C (Sgr C) region, along with some as-yet unidentified features. Credit: NASA, ESA, CSA, STScI, S. Crowe (UVA).

Thanks to its infrared capabilities, the James Webb Space Telescope (JWST) allows astronomers to peer through the gas and dust clogging the Milky Way’s center, revealing never-before-seen features. One of the biggest mysteries is the star forming region called Sagittarius C, located about 300 light-years from the Milky Way’s supermassive black hole. An estimated 500,000 stars are forming in this region that’s being blasted by radiation from the densely packed stars. How can they form in such an intense environment?

Right now, astronomers can’t explain it.

October 25, 2023October 25, 2023 by Evan Gough

Astronomers Want JWST to Study the Milky Way Core for Hundreds of Hours

This overview of the Milky Way's Galactic Center (GC) shows the region of the proposed JWST survey. Image Credit: NASA/JPL-Caltech/S. Stolovy (Spitzer Science Center/Caltech)

To understand the Universe, we need to understand the extreme processes that shape it and drive its evolution. Things like supermassive black holes (SMBHs,) supernovae, massive reservoirs of dense gas, and crowds of stars both on and off the main sequence. Fortunately there’s a place where these objects dwell in close proximity to one another: the Milky Way’s Galactic Center (GC.)

October 20, 2023October 20, 2023 by Nancy Atkinson

Astronomers Release a Cosmic Atlas of 380,000 Galaxies in our Neighborhood

Optical mosaics of 42 galaxies from the SGA-2020 sorted by increasing angular diameter from the top-left to the bottom-right. This figure illustrates the tremendous range of types, sizes, colors and surface brightness profiles, internal structure, and environments of the galaxies in the SGA. Credit: CTIO/NOIRLab/DOE/NSF/AURA/J. Moustakas.

The Milky Way is just one galaxy in a vast cosmic web that makes up the Universe’s large-scale structure. While ESA’s Gaia spacecraft is building a map of our stellar neighborhood, a team of astronomers with the Dark Energy Spectroscopic Instrument (DESI) Legacy Survey have released a comprehensive galactic map that includes all the data from three wide-ranging surveys completed between 2014 and 2017. Called the Siena Galaxy Atlas (SGA), it contains the distance, location, and chemical profile of 380,000 galaxies across half of the night sky.

“Previous galaxy compilations have been plagued by incorrect positions, sizes and shapes of galaxies, and also contained entries which were not galaxies but stars or artifacts,” explained Arjun Dey, an astronomer with NOIRLab, who was involved in the project. “The SGA cleans all this up for a large part of the sky. It also provides the best brightness measurements for galaxies, something we have not reliably had before for a sample of this size.”

October 12, 2023October 12, 2023 by Evan Gough

New Stars Forming Uncomfortably Close to the Milky Way’s Supermassive Black Hole

Artist view of an active supermassive black hole. Credit: ESO/L. Calçada

Astronomers examining a star cluster near Sgr A*, the Milky Way’s supermassive black hole, found that the cluster has some unusually young members for its location. That’s difficult to explain since the region so close to the powerful black hole is infused with powerful radiation and dominated by the black hole’s extremely powerful gravitational force. According to our understanding of stellar formation, young stars shouldn’t be there.

September 30, 2023September 30, 2023 by Brian Koberlein

The Milky Way's Mass is Much Lower Than We Thought

The rotation curve of our galaxy compared to the Keplerian rotation curve. Credit: Jiao, Hammer et al. / Observatoire de Paris – PSL / CNRS / ESA / Gaia / ESO / S. Brunier

How massive is the Milky Way? It’s an easy question to ask, but a difficult one to answer. Imagine a single cell in your body trying to determine your total mass, and you get an idea of how difficult it can be. Despite the challenges, a new study has calculated an accurate mass of our galaxy, and it’s smaller than we thought.

September 17, 2023September 17, 2023 by Brian Koberlein

The Milky Way's Disk is Warped. Is That Because our Dark Matter Halo is Tilted?

Illustration of the Milky Way's warped shape. Credit: ESA/Stefan Payne-Wardenaar

It’s difficult to determine the shape of our galaxy. So difficult that only in the last century did we learn that the Milky Way is just one galaxy among billions. So it’s not surprising that despite all our modern telescopes and spacecraft we are still mapping the shape of our galaxy. And one of the more interesting discoveries is that the Milky Way is warped. One explanation for this is that our galaxy has undergone collisions, but a new study argues that it’s caused by dark matter.

July 10, 2023July 11, 2023 by Carolyn Collins Petersen

Ancient Stars Somehow Survived Close to the Center of the Milky Way

The center of the Milky Way as seen from Chile. The core contains very old stars that date back to early in cosmic history. Credit: ESO/P.Horalek CC by 4.0.

The core of our Milky Way Galaxy draws astronomers’ attention like moths to a flame. That’s because there’s a lot going on there. Not only is there a supermassive black hole, but also populations of very ancient red giant stars that swarm the center. Most of them date back at least to the formation of the Galaxy.