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Milky Way Galaxy

Our home galaxy. The Milky Way is a spiral galaxy with four major arms containing young bright stars, gas, and dust. The mass of the Milky Way is estimated to be between 400 billion and one trillion times the mass of the Sun. The Milky Way’s diameter is about 100,000 light-years, with the Sun orbiting about 27,000 light-years from the galactic center. However, most of the galaxy’s mass consists of “dark matter” which encircles the Milky Way’s disk in a vast halo. Dark matter may account for 90 percent of the Milky Way’s mass.

Resources

Facts and Figures June 10, 2010
The Sun and our solar system lie in the "thin disk" of our galaxy.

The Milky Way May 21, 2010

Radio Programs

North Poles Looking north from the Milky Way March 25, 2023

Spring Milky Way The Milky Way brackets the night sky March 24, 2023

The Sunflower A good night for watching galaxies March 22, 2023

Declining Birth Rate The declining stellar birth rate March 17, 2023

Beetle Lights Guiding lights for dung beetles January 6, 2023

Milky Way A seldom-seen spectacle in the night sky August 26, 2022

Odd Source Something new in the heart of the galaxy July 19, 2022

Bubbly Surroundings New stars “bubble” to life March 31, 2022

More Moon and Taurus Gazing toward the galactic rim March 9, 2022

Smith’s Cloud Getting ready for some fireworks December 2, 2021

Longer Arm Stretching our galactic neighborhood December 1, 2021

Puffy Disk A small galaxy with a big impact November 30, 2021

Age of the Milky Way Measuring the age of the Milky Way November 29, 2021

Anti-Stars Looking for anti-stars August 18, 2021

Spiral Arms Bright arms for beautiful galaxies August 13, 2021

Safe Neighborhood A safe neighborhood in the Milky Way July 27, 2021

Listening In “Listening” to the center of the galaxy July 8, 2021

Brighter Black Hole A big display by an underachiever July 7, 2021

A Wild Ride Going for a ride in the heart of the galaxy July 6, 2021

In the Middle Looking into the middle of the galaxy July 5, 2021

Jhelum Stream Looping around the Milky Way June 18, 2021

Galactic Archaeology Digging into the history of the Milky Way June 17, 2021

Farthest Stars A star at the edge of the galaxy May 15, 2021

Big Detectors A search for tiny particles in big planets February 26, 2021

Wider Disk Looking for the edge of the galaxy November 13, 2020

Galactic Ripples Rippling through the Milky Way September 7, 2020

Impressive Clusters A land of monster star clusters August 20, 2020

Sagittarius Bar Stepping up to the Milky Way’s bar August 19, 2020

VX Sagittarii A monster among monsters August 18, 2020

Sagittarius Nurseries Starbirth in the Milky Way August 16, 2020

Sagittarius A high-speed ride ’round the galaxy August 15, 2020

Population II Stars Stars young and old in the Milky Way August 11, 2020

Scorpius A bright scorpion in the summer sky August 4, 2020

North Pole Aiming away from the Milky Way May 9, 2020

Venus and El Nath Pointing to the edge of the galaxy May 2, 2020

The Great Debate Debating the size of the universe April 24, 2020

A Dull Neighborhood Living in a dull neighborhood February 24, 2020

On the Edge On the edge of a spiral arm December 27, 2019

Getting Bigger The Milky Way gets bigger December 26, 2019

Adopted Cluster The Milky Way adopts a star cluster November 30, 2019

Galactic Twin A galactic twin in the evening sky October 27, 2019

Black Holes Galore Black holes in the Milky Way September 26, 2019

Galactic Collision Heading for a galactic pile-up August 21, 2019

Galaxies Adding some lines to your address August 19, 2019

Starburst The Milky Way gets busy August 18, 2019

Hidden Galaxy A close galaxy hides from view August 1, 2019

Dark Companion Black holes in the heart of the galaxy July 31, 2019

Quiet Monster A quiet monster flares up July 30, 2019

Baade’s Window A window into the heart of the galaxy July 1, 2019

Massive Milky Way Taking the measure of the Milky Way June 24, 2019

Arcturus Stream Streaming through the galaxy April 9, 2019

Galactic Magnet A giant magnet at the heart of the galaxy March 6, 2019

Mergers Giant galactic mergers February 14, 2019

Milky Way Halo A dark halo around the Milky Way January 24, 2019

Milky Way Mapping Mapping our home galaxy January 23, 2019

Stars Old and Young Stars old and young December 9, 2018

Barred Spirals Bellying up to the galactic bar November 6, 2018

Equal Galaxies? Balancing two big galaxies September 18, 2018

Black Hole Bonanza Black holes by the hundreds August 31, 2018

NGC 6397 Taking the measure of a star cluster August 12, 2018

Star Clouds Bright clouds in the Milky Way August 7, 2018

Dark Clouds Clouds darken the Milky Way August 6, 2018

Palomar 5 Tracing the bulk of the Milky Way July 11, 2018

IRS 7 A giant in the heart of the Milky Way July 10, 2018

Summer Milky Way The outline of our galactic home July 8, 2018

Close Clusters Two star clusters that stick together May 12, 2018

Camelopardalis Darkness above the Milky Way April 8, 2018

Streamers New arrivals in the Milky Way April 3, 2018

Winter Milky Way Gazing beyond the starry Milky Way February 12, 2018

Milky Way Center Discovering the galaxy’s distant heart August 26, 2017

Black-Hole Blobs A black hole fires some rockets August 12, 2017

Far, Far Away Mapping the distance to the galactic center July 22, 2017

Heading North Heading north through the Milky Way May 26, 2017

Event Horizon Telescope Looking for a giant black hole April 4, 2017

Local Group IV A collision course for the Milky Way January 12, 2017

Local Group III A faint satellite of the Milky Way January 11, 2017

Featured Images

diagram showing the local arm and other major spiral arms of the milky way galaxy

Big Arm December 1, 2021
hubble view of the core of the milky way

Galactic Heart July 5, 2021

Star Stream June 18, 2021
New view of the Milky Way Galaxy

Milky Way Bar August 19, 2020
Gaia view of the Milky Way, 2020

A Billion Stars May 28, 2020
Harlow Shapley (left), Heber Curtis

The Great Debate April 24, 2020
Paths of stars that pass close to the supermassive black hole at the center of the Milky Way Galaxy

Jumbled Stars April 18, 2020
X-ray views of the magnetar near the center of the galaxy

Galactic magnet March 6, 2019
Milky Way Dark Rift

Dark Rift August 6, 2018
Milky Way above Glacier National Park

Galactic Home July 8, 2018
A swirl of stars at the center of the Milky Way contains a supermassive black hole

Looking for Darkness April 4, 2017
sequence of images depicting the merger of M31 and Milky Way galaxies

Crash Course January 11, 2017
Labeled structure of the Milky Way galaxy

Arming the Milky Way September 28, 2016
Map of the Milky Way's spiral arms

Starry Arms July 25, 2016
Multi-wavelength view of the center of the Milky Way galaxy

Galactic Hub August 13, 2015
Artist's concept of Fermi bubbles

Blowing Bubbles July 20, 2015
Hubble Space Telescope view of the core of M13, a globular cluster in Hercules

Old Sparklers May 12, 2015
G2 survives its swing around the black hole at the center of the Milky Way

Narrow Escape March 27, 2015
The Milky Way galaxy's spiral arms

Arming the Milky Way February 18, 2015