QUESTION: For school I am doing research on The Milky Way. My teacher wants us to find an expert and ask him/her 10 good questions about the subject. I can't find any sites with anyone's email address or anything like that. Know of any good sites or anyone that is an expert on this subject? Thanks!

ANSWER: Hi Aspynne

I am not really an astro-physicist, who could answer technical questions about the Milky Way.  I know more about telescopes than about galaxies.  But if you want to ask me some questions, I will do my best to answer them!

Paul Wagner

---------- FOLLOW-UP ----------

QUESTION: Thanks for replying! My teacher gave us further information that we had to choose three top questions, so you'll only have to answer three. 1. What is the biggest planet in the Milky Way? 2. Star? 3. How fast does light travel from one end and back? If you can't answer, it's alright! Aspynne

HI Aspynne

Here are my thoughts:

1.  Jupiter is the biggest planet in our solar system, but we've found so many planets in the Milky Way that it's hard to keep track.  And we keep finding more of them.  I bet by the time I send you this answer, there will be new entries in this category.  IN 2012 astronomers annouced this: In a rare direct photo of a world beyond Earth, astronomers have spotted a planet 13 times more massive than Jupiter, the largest planet in our own solar system.

The planet orbits a star called Kappa Andromedae that is 2.5 times the mass of the sun and is located 170 light-years away from Earth.

Read more:

2.  The biggest star in the Milky Way?  WE don't really know, because we can't see most of the stars in the Milky Way.  We do know about some large ones, like these--but you have to remember that a lot of stars in the Milky Way are on the far side of the galactic center, and hidden from view:

VY Canis Majoris

This red hypergiant star is by far the largest known. It has an estimated radius between 1800 and 2100 times the radius of our Sun. With this size it would reach nearly to the orbit of Saturn if placed in our solar system. The star is located roughly 4,900 light-years from Earth in the constellation Canis Majoris.

VV Cephei A

Located in the constellation Cepheus, about 2,400 light-years from Earth, this red hypergiant star is estimated to be between 1,600 and 1,900 times the radius of the Sun.

Mu Cephei

Also located in the constellation Cepheus, this red supergiant is about 1650 times the radius of our Sun. It is also one of the most luminous stars in the Milky Way galaxy, at more than 38,000 times the Sun's luminosity.

3.  We estimate that the Milky Way is about 100,000 light years in diameter, so it would take like about 200,000 years to go from one side to the other and back.  But it's a very thin disk--it's only about 1,000 light years thick!

Hope that helps.  If you look, you can find most of these answers on various websites on the internet---and see some great photos of things too!

Paul Wagner  


All Answers

Answers by Expert:

Ask Experts


Paul Wagner


Astronomy and telescope making. Have made at least seven telescopes, both refractors and reflectors, and have spent 30 years looking at the nighttime sky.

©2017 All rights reserved.