When you were born, light reflected from your body started radiating in all directions. Some of this light would have headed on into space, journeying to the stars. Your light cone lists all the stars your light could have reached by now.
Conversely, the light you see from the stars in the night sky set out on its journey some years ago. If a star is one light year away (that's a measurement of distance, not time) then its light would take one year to reach you. So your light cone also represents stars whose light, now reaching the earth, set off within your lifetime.
In general relativity, the surface of the light cone represents the boundary of your causal future and past. That means that any star outside your light cone hasn't influenced you directly, nor have you influenced it.
Your light cone is supplied as an RSS feed, so you need an RSS reader or news aggregator. RSS readers collect together RSS feeds from various sources (e.g. news sites, weather, weblogs) and present them in a cohesive format, rather like syndicated news stories being assembled into a newspaper. There are quite a few of these available, some for free. Here's a list.
Enter your birthdate in the form below and submit the form. The form will disappear, and you will see a link to your feed. Click it. Unless you're familiar with XML, the feed will look a bit odd. Don't worry, it's designed to be read by your computer. Add the address of the feed (from your browser's address bar) into your RSS reader. As time passes, new stars will appear at the top of your feed as your light cone envelops them!
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In December 2003 I came across Matt Webb's Light Cone RSS Feed, which I thought was a neat idea. Almost immediately however, the site disappeared, so I decided to build my own. Matt's site is now back online.
Data was provided by the Internet Stellar Database, permission kindly granted by Roger Wilcox.
This project was written by Matthew Walker on the morning of 4 January 2004 in the ColdFusion language from Macromedia. It was a beautiful sunny day and he really should have been outside playing.
The stellar data used here is not comprehensive beyond about 75 light years. So if you are over 75 years of age, results may be less satisfactory.