Gaia Gives Our Galaxy a, “Physical;” Height, Weight, Girth (?) Determined

Alex Wierbinski's picture

By Alex Wierbinski - Posted on 07 March 2019


Globular Clusters Decorate Milky Way
Artist impresses us with accurate conception of globular clusters around Milky Way, by ESA/Hubble, NASA, L. Calçada.
Artist impresses us with accurate conception of globular clusters around Milky Way, by ESA/Hubble, NASA, L. Calçada.


Gaia Gives Our Galaxy a, “Physical;” Height, Weight, Girth (?) Determined

Hubble & Gaia accurately weigh the Milky Way,
ESA/Hubble Information Centre, March 7, 2019.


Size & Weight
"...the Milky Way weighs in at about 1.5 trillion solar masses within a radius of 129 000 light-years from the galactic centre."

Previous Estimates
"...ranged from 500 billion to 3 trillion times the mass of the Sun. This huge uncertainty arose primarily from the different methods used for measuring the distribution of dark matter — which makes up about 90% of the mass of the galaxy."


Modern Measurement
Globular Cluster Speeds
"...relied on measuring the velocities of globular clusters — dense star clusters that orbit the spiral disc of the galaxy at great distances…"

(Measuring the movements of Globular Clusters revealed the hidden, “dark,” gravity.)

Three-D Tracking
"...we were able to also measure the sideways motion of the clusters, from which the total velocity, and consequently the galactic mass, can be calculated.”

3-D Milky Way Map
"Gaia was designed to create a precise three-dimensional map of astronomical objects throughout the Milky Way and to track their motions. Its second data release includes measurements of globular clusters as far as 65 000 light-years from Earth."



ESA: The Instrument

ESA: Mission & News

Wiki about Gaia


Our Galaxy
Recent Research

At the Center of this Mess

At the Center of Our Galaxy, (Sag A*); A Star Orbits Our Black Hole at 2.7% of Light Speed

To get a visual idea of the notion of a star being accelerated around a black hole, see the amazing black holes video below showing many, many stars being swirled, shot off, shredded, and some eaten by a few billions years of black hole swarm activity:

OUR GALAXY: Centered on a Supermassive Black Hole & a Swirling Swarm of Hundreds of Smaller Holes?

Sag A* Orbital Objects



In Our Galactic Neighborhood: Is the Milky Way "normal?"  (are you?)


Galactic Evolution: How the Milky Way Galaxy Came to Be



More Information

Trail Guide

Star Chart
Sag A*
17h 45m, -29
Just off the spout of the teapot...


Our Galaxy & Deep Space Information



Bring a Star Chart on your Dark Sky Backpacking Trips!

Field Use Star Wheel




Astro-Physics News


March 2019 News of Man & Nature








Nature News


Climate Destruction News



Bee News

Bear News

Spider Forum

Bird News

Small Mammals

Frogs and Reptiles

Butterfly News


Health and Fitness

Mountain Safety

Mosquito News

Female Trail

High Sierra History


Astro-Phys, Space, & Science News

High Sierra Geology News

Fish, Oceans, & Water News



All High Sierra News





Gaia, Hubble, measure, weigh, Milky Way, dark matter, galaxy, globular clusters


Powered by Drupal, an open source content management system

Latest News: RSS FEED

Syndicate content

Support Tahoe to Whitney

The Tahoe to Whitney Trail Guide and Magazine are walked, written, funded, and supported by my efforts, with the help of kindred spirits and my sister.

We offer valuable Trail Guide, Skills, Weather, News and Analysis.

My goal is to get you out to see your natural and social potential. Help me keep this unique resource accessible and expanding towards its potential. We've a lot of miles to cover ahead...

If you feel these efforts are valuable, I'm cordially inviting you to support them, here:



I am currently working towards publishing the completed guide between Tahoe & Yosemite as an e-book, while converting this "blog" to a fine magazine format. You will like the results! Help Tahoe to Whitney reach its potential!


Why Support Tahoe to Whitney?
Mission Statement