Astropotamus just came back from a most delightful journey. 1000 years ago, a star exploded and we got to see it. Well, actually more like 7500 years ago, a star exploded and 1000 years ago, we got to see it. SN 1054 is the birthplace of the Crab Nebula. Though it’s close to us (about 6500 light years away) it’s still very very far away and somewhat hard to see. Almost impossible with the naked eye, in fact. But it has a really good story.
Nebula is Latin for “cloud.” If you’ve ever seen some of the beautiful pictures that the Hubble Space Telescope has sent back, then you know what a nebula is. Essentially, a cloud of gas, dust, ice, or other debris in space causes light to reflect off of it and head in our direction (called a reflection nebula), or to glow from the heat of its own particles (an emission nebula), or to block the light from something behind it (a dark nebula). In any case, they make for stunning images when done well.
The problem with nebula is that they are so diffuse, when compared with stars, and that they “shine” (if at all) so dimly (again, compared to stars) that it is almost impossible to see them with the naked eye. If you do see them, they are usually only seen as faint smudges against the dark blackness of space.
Nebulae (the plural of nebula) and globular clusters and galaxies and lots of other things are called deep space objects because they are outside our solar system. Stars, besides our own, are also outside our solar system, but they are not included in the category of deep space objects. These are among the finest things a time traveling Astropotamus could hope to glimpse, since they are so beautiful and mysterious. The problem is that they often don’t send light in visible wavelengths – they do so in radio waves, infrared, and x-rays. Things our eyes just don’t see.
Which brings us back to SN 1054.
In July of 1054 CE (about 1000 years ago), a star in the constellation Taurus exploded. Wait. No – I forgot we have to time travel. In July or so of about 5500 BCE, back when Agriculture was first invented in Egypt, a star in the constellation Taurus exploded. The star was about 6500 light years from Earth, so in 1054, we got to see its explosive light show. It was so bright it was visible in the daytime skies.
You can read all about this by searching Google for SN 1054, but the more important thing is that when the star exploded, it threw off its outer shell of gas into a billowing cloud of superheated particles, all traveling at incredible speeds away from the remaining neutron star left behind. 1000 years after the star exploded, it looks as we see it today in the early 21st century.
Most of what you see in this picture is only visible with a lot of specialized imaging devices and a lot of computer processing. With your eye, even with a powerful Time Machine, you’ll just barely be able to make out the filament structure and you’ll be more likely than not to just see a black and white style image than any color. But that’s not the exciting part.
The exciting part is that the Crab Nebula, as this supernova remnant is called, is still growing. Tomorrow, it will be bigger than it is today. A year from now – bigger still. A generation from now, this same image might look different due to the nature of the gas expanding at super fast speeds away from the center.
This is what Astropotamuses live for – understanding that time travel really is possible. Knowing that what I see with the Time Machine today is really what it looked like 6500 years ago means that 6500 years from now, someone else using a Time Machine will see what it looks like today. And my goal is to get my own image of the Crab Nebula so I can stop every now and then and see what the supervnova looked like in 4500 BCE (which is how I see it today), captured forever in a fleeting moment of time in a digital image.