If light travelled really slow…

The speed of light is one of the fundamental constants in the universe (along with the Gravitational constant, permitivitty etc.). Changing any constant even slightly will have deadly consequences. But if we manage to survive (somehow), we would find ourselves in a very ‘interesting’ universe.

The constant for the speed of electromagnetic waves ‘c’ has a value of 300 million metres/second. Imagine that some one hacks the universe’s secure servers and changes ‘c’ to 1. The following is a roughly chronological list of things that would happen in a universal conspiracy to end the human race:

1. We would shrivel up and die

Literally. The speed of light is directly related to the strength of electromagnetic force. This is the same force that prevents you from falling out of your house when you lean against a wall, or from falling through a chair while you are sitting. It also helps you keep you in shape while gravity is doing its best to pull you to the ground. If the speed of light were to suddenly decrease by several orders of magnitude, all matter (or most of it) would start to collapse under its own gravity. The world would literally shrink out of existence.

2. The sun would go out

Again: literally. As matter collapses under its own gravity, its gravitational pull on the surface increases and stuff like rebellious atoms and people who can afford a rocket will need higher speeds to escape a body’s gravity. Eventually the ‘escape velocity would exceed the speed of light. And since classically one cannot productively travel faster than light, including light, all matter with high escape velocities would become black holes, including the sun and the earth and all the planets in the solar system.

3. Time will s l   o    w     d       o        w          n

If by any miracle we are still alive we will notice (that’s putting it subtly) that everything has shrunk. The gravitational field will be extremely strong. And since light is so slow, our every motion will be at relativistic speeds. That means that on a jolly morning when I decide to go out for a walk, I might as well come back to my house to find it in ruins from age. In other words we wouldn’t need to wait an entire week for new episodes of our favourite shows.

4. The world will look W13rD

Take a look at these pictures:

Light captured at super high frame rates,

Light captured at super high frame rates,

Simulated reflection of light at super slow motion.

Simulated reflection of light at super slow motion.

This is what light looks like if it is slowed down. On a post-hacked universe, you could stand behind something heavy and literally make copies of yourself (gravitational lensing, kage bunshin no jutsu! for Naruto fans). Since light will bend under extreme gravity, you will be able to see whats happening on the other side of the earth, or the back of your head for that matter. You could swipe your hand through the ‘air’ and turn your palm into a black hole and deflect bullets with a wave of your hand.

All in good time. In the real world we would just stop existing the moment a single constant was changed. If all universal constants were scaled down proportionally, we might have a chance, but alas we don’t even know all of them. So why did I conjure images of a Matrix/Naruto/Avengers/ Harry Potter universe? Simple. I just got carried away.


Posted in Class, Light, Science | Tagged , , , , , , , | Comments Off on If light travelled really slow…

Getting started…

Hi, my name is Megan and I am a Senior Math and Physics major at Vanderbilt University. This blog is going to be my thoughts and reflections on the ASTR 201 class that I am taking this semester. My intention is to take a look at the more mathematical and physical implications of the concepts that we study in the course, but the student who always wanted to be a philosophy major may come out from time to time.

taken by me

taken by me


Posted in Class | Tagged , | Comments Off on Getting started…

Intro post

Mt. Hood - by me

Mt. Hood in Portland – by me

Hi, my name’s Megan C.  I’m a Junior triple majoring in Computer Science, Math, and Political Science. I love the West Coast. I visit Portland often because my older sister lives there, but I’m hoping to get an internship in Seattle this summer.  This is a picture of Mount Hood, which is considered the most likely volcano to erupt in Oregon. You can see it from almost anywhere in the city, along with Mt. St. Helens, on a clear day.


Posted in Class | Tagged , , | Comments Off on Intro post

For my 2013 class…

If you’re in my Solar System class, please put a comment here showing that you’ve found my blog and that you’re following it.  Please include your first name and last name initial – let’s not have last names :)

Also make sure you have bookmarked the big class blog aggregator: Astro201 – The Solar System.  From there, you can follow everyone or specific classmates if you like.

from http://www.hdwallpapersimages.com/welcome-2013-hd-wallpapers/


Posted in Class | Tagged | Comments Off on For my 2013 class…

Slime molds are smart?

During class on Wednesday, I promised that I would post this story that I read on slime molds following the interstate system.  By the way, this is related to astronomy because “astrobiology” is part of astronomy :)

Photographic evidence!

Click to go to Gizmodo story

Slime molds on a US map - they start at the capital city and there is food (oats) at major urban centers - look at how they grow!

The scholarly journal article is from the preprint server called arXivAre motorways rational from a slime mold’s point of view?  They study 14 different countries and find that, in general, yes, they are rational :)  The Gizmodo article (“Slime Mold and Highways Take the Exact Same Paths“) is also a great synopsis.

What I find just awesome about this is that it seems the interstate system grows pretty naturally.  This makes sense because usually, big highways are the result of people (or animals) going from one place to another and finding the best route…  Why break new ground?  I’ve always felt that certain roads, especially in Atlanta, GA, are really just paved-over cowpaths… Only cows can meander so much in order to be lazy :)


Posted in Science | Tagged , , , | Comments Off on Slime molds are smart?

Astronomically, it IS an early spring!!

So I read this article and I had to share it with you – I think it’s very good :)

Article:  Spring Arrives With Equinox Tuesday, Earliest in Over a Century
by Joe Rao, SPACE.com Skywatching Columnist

As an introduction, here in Nashville, we’ve been experiencing a really mild spring – personally, I’m pretty happy about it because I go observing with the lab students a lot and it’s been so nice to not have to bundle up ;)  Thus we’ve been having an early spring meteorologically.

But let’s think about what the start of spring means ASTRONOMICALLY.  The start of spring is technically the date of the vernal equinox which technically is when the Sun’s position in the sky goes from being in the southern celestial hemisphere to being in the northern celestial hemisphere.  You can see this with Stellarium!!  Plus you can see how the actual location of the equinox in the sky (comparing it to the constellations) changes over time – this is called the precession of the equinoxes and it is why we are entering the Age of Aquarius!

Heliocentric vernal equinox

The vernal equinox location (see arrow) according to the heliocentric perspective.

Geocentric vernal equinox

The location of the vernal equinox according to a geocentric view

Here’s a lovely graph from Wolfram Alpha that shows the date of the vernal (spring) equinox for certain time periods (see axes ;) ):

Date of the vernal equinox VS time - from Wolfram Alpha

Note that we’re bottoming out for our cycle in the left graph (stupid axes if you ask me so it is kinda hard to see).  The short-period cyclic nature on the left shows the “resetting” every leap year and then the big jumps on the right plot show the effect of not having a leap year during century years (i.e., 1800, 1900, 2100, 2200) unless those years are divisible by 400 (i.e., 2000).  To learn more about this (and to see a better graph), go to Wikipedia :)  Dudes, on Wikipedia, I learned about the Iranian calendar which has 8 leap days in every 33 year time period – it’s more accurate :)

Anyway, the aforementioned article is a good article – Dr. G approved! ;)


Posted in Observables, Sun, Terrestrials | Tagged , , , | Comments Off on Astronomically, it IS an early spring!!

Awesome Planetary Formation Videos

Computer Model of Planetary Formation

In class on Monday, I showed a whole bunch of videos that show planetary formation – some showed certain parts better than others but they all are pretty awesome.  Just in case anyone wanted to look at them again, here they are:

  • Short, beginning of formation (from gas cloud to disk) from ESA – here
  • By NASA for the James Webb Space Telescope, uses data from computer models – here
  • Narration by Harrison Ford, I like that it has some timescale information in it, part of a larger series – here
  • From “Space with Sam Neill” Episode: “Star Stuff”, I really like how this one is done (I started it at 1:27) – here
  • If you liked the “Formation of the Moon” video from the end of class (it does happen to be one of my favorites despite the speeding up of some events that they did), it is here

 

Below is an image of the Orion Nebula (we can see it during our observations this semester ;) ) from the Hubble Space Telescope showing some of the protoplanetary disks that have been found in this nebula.  Look!!!  New baby planetary systems! :)

Click to go to the Astronomy Picture of the Day website for this image.

"Proplyds" (protoplanetary disks) in the Orion Nebula


Posted in Class, Exoplanets, SolarSystem | Tagged , , , , | Comments Off on Awesome Planetary Formation Videos

Go outside on March 12 and 13!!

Mercury, Venus, and the Moon aligned. Taken from Paranal Observatory in Chile, March 2008 by Yuri Beletsky.

Right when we come back from Spring Break, we will be able to see a planetary conjunction!  You will be able to see Jupiter and Venus be within three degrees of each other and that’s an especially close separation and will be especially brilliant due to the biology of your eyeball – they will be so close that the “hi-def” part of your eye (the fovea) will be activated.  Here is a NASA article about it: Cold and Spellbinding: An Alignment of Planets in the Sunset Sky

Note that this conjunction is just the kind of thing that early astronomers were trying to predict using the Geocentric (Ptolemaic) model of the Solar System (with all of the epicycles and such).  To be honest, the geocentric model worked pretty well at the beginning, but errors combined over the centuries.  This conjunction is also the kind of thing that astronomers used the Heliocentric model of Copernicus to predict but was just as inaccurate due to Copernicus’ need for perfect circles.  Kepler’s models helped take care of the prediction problems thus the heliocentric model became the accepted model of the Solar System :)

To see how the conjunction works, I’ve put a line on this picture from the NASA/JPL Solar System Simulator.  Note that the line from Earth passes by both Venus and Jupiter :)

Solar System on March 12, 2012

Solar System diagram for March 12, 2012 to illustrate the conjunction of Jupiter and Venus. Note that Venus and Jupiter are along the same line-of-sight from Earth.


Posted in Observables, Science, SolarSystem | Tagged , , , , , | Comments Off on Go outside on March 12 and 13!!

Solar System Graphs

Image


Posted in Class, SolarSystem | Tagged | Comments Off on Solar System Graphs

Buying a star

Last week, I brought the portable planetarium that I run (the Fisk-Vanderbilt NASA Astronomy Roadshow) to a school north of Nashville.  From both the parents and the students, I got questions about buying a star for someone.  I get these questions a lot – from people when I do outreach, from friends for whom I’m “their” astrophysicist, from students…  It is a really nice idea and very sweet, but IT IS NOT WORTH IT.  Should you do buy a star for someone, you are giving your money away to some opportunists.  The star name company will give you a nice certificate, put your name in a database, and take $50 (or more).  However, there are several companies out there, each with their own databases, and they don’t talk to each other.  “Your” star could also be several other people’s star.  Also, the naming is in no way official – no astronomer will ever, EVER call your star by the name you “buy” – astronomers have our own, internationally agreed upon, usually boring numeric names/designations.

More importantly, the sky is free :)  We should keep it that way.

If you would like more information


Posted in Observables, Outreach, Science | Tagged , , | Comments Off on Buying a star