Elliptical: Circular or elliptical in shape, have no gas and dust, with no visible bright stars or spiral patterns. Elliptical galaxies probably comprise about 60 percent of the galaxies in the universe. Size -- most are small (about 1 percent the diameter of the Milky Way), but some are about five times larger than the diameter of the Milky Way. Spiral : The Milky Way is one of the larger spiral galaxies. They're bright and distinctly disk-shaped, with hot gas, dust and bright stars in the spiral arms. Because spiral galaxies are bright, they make up most of the visible galaxies, but they're thought to make up only about 20 percent of the galaxies in the universe. Barred Spiral : Obvious disk shape with elongated, bright centers and well-defined spiral arms. SBa galaxies have large nuclear bulges and tightly wound spiral arms, while SBc galaxies have small bulges and loosely wound arms (recent evidence suggests that the Milky Way is a SBc galaxy). Irregular : These are small, faint galaxies with large clouds of gas and­ dust, but no spiral arms or bright centers. Irregular galaxies contain a mixture of old and new stars and tend to be small, about 1 percent to 25 percent of the Milky Way's diameter.

Spiral galaxy NGC7331, 50 million light years away in the constellation Pegasus

M33 galaxy 3 million light years away

Spiral galaxies merging

Cold dust clouds: areas of star formation. Not visible to the naked eye, but as seen in infra-red

Crab Nebula: remains of 1054 supernova 10 light years away In the centre is a pulsar (neutron star) as massive as the sun But the size of a small town.

This huge puff ball was once a star. One thousand years ago, in the year 1006 a new star was recorded in the sky that today we know was really an existing star exploding. The resulting expanding gas from the supernova is still visible with telescopes today, continues to expand, and now spans over 70 light years. SN 1006 glows in every type of light. The above image was captured by the orbiting Chandra Observatory in X-ray light. SN 1006 is thought to have once been a white dwarf that exploded when gas being dumped onto it by its binary star companion caused it to go supernova. In the foreground are stars that have nothing to do with the supernova.

At the center of our Milky Way Galaxy lies a black hole with over 2 million times the mass of the Sun. Once a controversial claim, this astounding conclusion is now virtually inescapable and based on observations of stars orbiting very near the galactic center. Using a very large telescope and a sophisticated infrared camera, astronomers patiently followed the orbit of a particular star, designated S2, as it came within about 17 light-hours of the center of the Milky Way (about 3 times the radius of Pluto's orbit). Their results show that S2 is moving under the influence of the enormous gravity of an unseen object that must be extremely compact -- a supermassive black hole. This near-infrared image shows the crowded inner 2 light-years of the Milky Way with the exact position of the galactic center indicated by arrows.

The Hubble telescope looked at a black area in space, where we saw no stars, for 13 days. When we examined the image we saw the universe as it was 9 billion years ago when it was ¼ the size it is today. Bluer objects contain young stars and/or are relatively close, while redder objects contain older stellar populations and/or farther away.

The James Webb space telescope will detect infrared radiation and observe the universe as it was 13 billion years ago and was much smaller than the Hubble telescope saw. This image is what we expect to see: galaxies crammed into each other since the universe was smaller.

Actual Hubble image (left) of universe 9 billion years ago versus Computer simulation of what James Webb (right) may find in the universe 13 billion years ago.