Solar Systems
in the Making?

The nebular hypothesis for the origin of our Solar System has been bolstered by a variety of recent observations that look very much like star and planetary systems in various stages of formation.

New Solar Systems

Recent Hubble Space Telescope observations shed considerable light on the birth of stars and associated planetary systems. The following image shows regions in the Orion Nebula where solar systems may be forming.

Regions in the Orion Nebula where solar systems appear to be forming

The Orion Nebula is approximately 1500 light years from Earth. It is visible to the naked eye as the middle "star" in the sword of the constellation Orion. These images were taken with the Wide Field Planetary Camera 2 of the Hubble Space Telescope (C.R. O'Dell, Rice University). Details of the images show several protoplanetary disks ( proplyds ), including a single dark disk surrounding a central star (Ref). The lower left inset figure shows a drawing giving the approximate scale of our Solar System relative to the proplyd.

Here is a movie illustrating these protoplanetary disks in the Orion Nebula source), here is a further discussion of these planetary systems now forming in Orion.

More Star-Forming Regions

Many other star-forming regions are known. In addition to the Eagle Nebula discussed below, here are images and discussion of In each of these examples there is strong evidence that stars are being born in the region shown in the image; presumably, at least in some of the cases, attendant solar systems are being formed also.

Star Formation in the Eagle Nebula

The following images show examples in the Eagle Nebula of regions where stars (and possibly solar systems) appear to be forming.

Star-Birth Clouds in M16 (Eagle Nebula). J. Hester and P. Scowon (Arizona St. Univ.), November 2, 1995. Taken with NASA Hubble Space Telescope, WFPC2

The scale of the image on the left is about 1 light year. The blowup on the right shows finger-like structures that are thought to be regions in which new stars are being formed. The tips of these finger-like objects are about the size of our Solar System! Here is a movie of these star-forming regions in the Eagle Nebula made with the Hubble Space Telescope (Source). This movie is about as close as you are ever going to get to the bridge of the Starship Enterprise!

Planets Around other Stars

In recent years rather conclusive evidence has accumulated for planets orbiting other stars. This evidence comes from the gravitational perturbations exerted on the star by the unseen companion planet that can be exposed by very accurate measurement of the radial velocity of the star (see the related discussion of detecting unseen companions in binary star systems). These measurements require that variations in the radial velocity of order 10 meters per second be detected relative to a total radial velocity typically of order 10-100 kilometers per second. Here is more information about some of the first discovered planets, and here is an online Extrasolar Planets Encyclopedia with some catalogs. There are currently (2004) 120 confirmed extra-solar planets in 105 extra-solar planetary systems.