Hubble Tuning Fork Interactive Diagram
November 19, 2012

Interactive Diagram Shows Hubble Tuning Fork

Lee Rannals for - Your Universe Online

The European Space Agency (ESA) released an image this week of an interactive diagram known as the Hubble Tuning Fork.

The diagram helps to describe the shape of galaxies, which can come in all different sizes. It ranges between elliptical galaxies, intermediate spirals, barred spirals and irregular shapes.

The interactive map gives the examples of the different shapes of the galaxies, as well as a description in type, morphology, distance and size.

ESA said the diagram represents 61 nearby galaxies studied by the space agency's Herschel and NASA's Spitzer telescopes.

The galaxies are located 10 to 100 million light-years from Earth and were surveyed as part of two programs.

Images in the diagrams are three-color composite showing warm dust detected by Spitzer at 24 microns, and cooler dust traced by Herschel at 100 microns and 250 microns.

The galaxies chosen were picked to cover a range of characteristics to help improve the understanding of the processes linking star formation to local interstellar environment in the nearby Universe.

The tuning fork shape presents elliptical galaxies along the handle. The further along the handle of these galaxies go towards the fork, the more elongated they appear. The two populations of spiral galaxies are located on the tuning fork's "prongs" to differentiate between spiral galaxies with a central bar, and those without.

The "irregular" galaxies conform to neither group, possibly due to a collision or merging that disrupted their shape.

Astronomer Edwin Hubble classified these galaxies by means of a diagram known as the Hubble Tuning Fork.