Hopefully the previous preliminary assignment put the Solar System into some sort of scale. Let's now do the same for our stellar neighbourhood. Spend a coffee break with 100 000 stars or NASA's Eye on exoplanets app. Exoplanet: a planet orbiting a star other than our Sun.


100 000 stars

(Some students have not been able to get 100 000 stars work on all browsers. I have successfully tested it with latest (as of Dec. 2022) Chrome, Firefox, Brave, Opera, and Epic browsers on Windows. If you cannot get it work, try disabling your script-/adblockers or privacy addons temporarily. If it doesn't work even then, watch the video instead.)

  1. Go here and click "Take a tour" on the top-left corner [https://stars.chromeexperiments.com].
  2. After the tour, zoom out (using the slide on the right) to see the inner planets (Mercury - Mars), outer planets (Jupiter - Neptune), and the Oort cloud. Turn the model around and keep zooming out until you see the nearest stars. Do you recognise any star names? (Click the name tags for information about the star.)
  3. This is our neighbourhood, and these are the stars that we have all seen countless times. Eventually, zoom out to the max to see the whole Milky Way and, finally, slowly zoom back in, all the way to the Sun. 
  4. Play with the model; twist it around, click on star names and read about a few, center on different stars and see how things look from there, and most importantly, think about it. Imagine a trip from Earth to the nearest stars.
Eyes on exoplanets

  1. Go here and click "View from: Earth" on the bottom-left corner [https://eyes.nasa.gov/apps/exo/#/].
  2. Get an overview of the stars as seen from the Earth. Rotate around, and maybe click for an interesting place to use as a reference "observatory".
  3. The stars marked on the sky are not just "all the stars" -- the app only highlights stars that we know to have planets orbiting them-. In other words, they are not just stars, they are other solar systems. Pick one or two and zoom in. 
  4. Get back by clicking "Home" on the top right. You should see a view centered on the Sun, with all the other nearby solar systems that have been discovered so far around us. 
  5. You can probably see a clear "beam" of solar systems -- that's not a real beam of course, but shows a direction where very deep surveys have been made, and therefore show a lot more discovered exoplanets. That's like a beam of a flashlight: where we point it, we see thousands of planets everywhere. So far we have pointed it in just one general direction. Imagine how many more planets and solar systems we will find with time, when we have had enough time to look in all directions

Wait, was this the assignment?

Yes. Nothing needs to be submitted this time, just come to the lecture after having thought about the solar system and stellar neighbourhood, so that you have some experience and insight about our cosmic environment. We'll continue from this at the lecture.

Last modified: Friday, 9 December 2022, 2:28 PM