Saturday, January 24, 2009

Walking streets of gold

Here is a Hubble photograph of the planetary nebula NGC 2818, the gaseous shroud of a dying sun-like star, featured the other day on APOD (Astronomy Picture of the Day). Says APOD: "It could well offer a glimpse of the future that awaits our own Sun after spending another 5 billion years or so steadily using up hydrogen at its core, and then finally helium, as fuel for nuclear fusion." The red, green, and blue hues represent emission from nitrogen, hydrogen, and oxygen atoms in the nebula. Click to enlarge.

It is difficult to look at this picture and not imagine that one is looking through the dome of night into another more ethereal domain. I am reminded of the famous wood engraving below, which seems to have first appeared in Camille Flammarion's 1888 book L'atmosphere: meteorologie populaire. For a long time, the image was thought to be medieval, but it probably originated with Flammarion himself.

In any case, it depicts a medieval pilgrim who has somehow arrived at a place where the Earth and the dome of night touch, and -- lo! -- he is able to peak through into a celestial realm. The same sort of sensation, I would suppose, that we experience looking at the Hubble photo of NGC 2818.

For as long as we have a historical record, humans have imagined a Heaven somewhere up there beyond the stars, a realm immune to earthly imperfections, woes and cares, where other beings, divine and immortal, hold sway, and where we might ourselves be transported after death.

And what have we discovered? There is no dome of night. There is no "up there." This earthly realm is replicated trillions of times over within a space that may for all we know be infinite. NGC 2818 is not a hole in the sky; it is the remnant of an exploded star 10,000 light-years away, a star not unlike our Sun.

The pilgrim In Flammarion's wood engraving can have a real peek at Heaven if he wishes. All he needs do is click his way to the Hubble web site. Heaven, as it turns out, is here, now, available to everyone -- even the naughty -- through the agency of science and technology.