In his book Universal Natural History and Theory of Heaven, published in 1755, Immanuel Kant proposed his nebular hypothesis of planet formation:

If we…consider this fundamental material of the planets whirling about in a state where it develops itself through the power of attraction and the mechanical consequence of the general law of repulsion, then we see a space which is contained between two planes standing not far from each other. All the particles we can conceive have their mathematically precise circular orbits on this common plane, each proportional to the extent of its distance and to the force of attraction which governs there. Because in such an arrangement they interfere with each other as little as possible, they would remain in this form for ever, if the force of attraction of these particles of basic matter did not then start to have an effect and initiate developments, thus producing the seeds of planets which are to arise. For as the elements moving around the sun in parallel circles take up positions where the distances from the sun are not very different, circles which, because of the equality in the parallel movements, are almost in relative calm in relation to each other, then the force of elements there with an excessive specific power of attraction begins at once a significant process of collecting the nearest particles for the development of a body. As the mass of its growing cluster increases, the power of attraction of this body expands, and elements from a wide area move to combine with it.

Kant’s hypothesis that planets form from dusty debris orbiting stars has now been confirmed.

The analysis of images collected by the Hubble Space Telescope (HST) in 2000 show that an extra-solar planet is orbiting a star in the same plane as the star’s disk of dust.

The planet, which is about the size of Jupiter, is orbiting a sun-like star called Epsilon Eridani, in the constellation Eridanus. At 10.5 light years away, the planet is the nearest extra-solar to be found so far. It is the kind of planet that could harbor extraterrestrial life.

The work was carried out by a University of Texas team led by Barbara E. McArthur, and is being presented today at the 38th Annual Division of Planetary Sciences meeting in Pasadena, California.

These images are unrelated to the new findings, but they’re so beautiful I couldn’t resist posting them. From top to bottom, the images are of a stellar spire in the Eagle Nebula, the Crab Nebula, the Black Eye galaxy (M64), and the barred spiral galaxy NGC1300. (From the HubbleSite.)

Incredibly, the view in the top image is 57 trillion miles high. One of the finger-like projections near the middle of the gaseous tower is about the same width as our solar system. The blue at the top of the image is glowing oxygen, and the red at the bottom is hydrogen. Inside the tower, stars may be forming as the gases swirl around due to the force of gravity. This puts the gases under immense pressure, increasing their temperature. Once that temperature is high enough, hydrogen nuclei begin fusing, and a star is born. The image was taken in November 2004.

The Crab nebula is a 6-light-year-wide supernova remnant about 6,500 light years away. It was recorded by Chinese and Japanese astronomers in 1054. This is a composite of 24 separate images taken by the HST between October 1999 and December 2000.

The Black Eye galaxy, or Messier Object 64 (M64) was formed by the collision of two galaxies. The galaxy is approximately 17 million light years from Earth. In the 1990s, it was discovered that gas in the outer regions of M64 rotates in the opposite direction to the gas and stars on the inside.

Because of the resolution of this image, blue and red supergiant stars, star clusters and star-forming regions can be made out in the arms of the spiral. This galaxy is approximately 69 million light years away, in the direction of the constellation Eridanus, where the planet investigated by McArthur and her team is located.