Categorizing Light and Seeing What’s in Between Stars
Maunakea Skies Reflection with Dr. Mark Rawlings of East Asian Observatory
‘Imiloa welcomed Dr. Mark Rawlings from East Asian Observatory / James Clerk Maxwell Telescope in November where he gave a presentation titled Long Wavelength Eyes on the Cosmos. He discussed how astronomers utilize different types of telescopes and different wavelengths of light to study unique objects in the Universe..
Light, scientifically known as Electromagnetic Radiation, comes in many different forms. To understand and differentiate types of light, scientists have created the Electromagnetic Spectrum (EM Spectrum), which organizes light based off of energy and wavelength.
Humans are only able see a small portion of the EM Spectrum with the naked eye. Telescopes such as the James Clerk Maxwell Telescope and UKIRT Telescope allow humans to discover and see deeper portions of the Em Spectrum.
Seeing what is between Stars
Spectroscopy is a process which allows scientists to see the “fingerprints” of what is causing light, and which types of materials may be interfering with light from an object. Dr. Rawlings utlizies this science as he studies the Interstellar Medium, the materials that exist between stars in the Milky Way. While the space between stars is mostly empty, there are small particles of dust (hydrocarbons, silicates) and gas. The largest of these dust grains are about the size of the particles that make up cigarette smoke. This is the material that over time is able to collect and form nebulae, stars and planets. The dust grains of the Interstellar Medium can absorb visible light and heat up, causing them to emit light in the infrared portion of the EM Spectrum.
Mysteries of the Interstellar Mediums are often exclusively studied using spectroscopy. One such mystery is the appearance of Diffuse Interstellar Bands (DIBs) in spectra of distant objects. DIBs are features of spectra caused by material in between stars, however the type of material that causes these features has remained a mystery for over 60 years. It is thought that these bands might be caused by hydrocarbons, such as those found in smoke (Polycyclic Aromatic Hydrocarbons) or even fullerene, which is commonly known as “buckyballs.”
The continuing study of this unique material between stars will help astronomers, such as Dr. Rawlings, provide new perspective on our little corner of the cosmos.
Pictures of the Orion Nebula using different wavelengths. Pictured left is a submilimeter light image taken with the JCMT (Image Credit: SCUBA-2 Orion: Gould Belt Survey & Carl Salji) and on the right is an infrared image taken with UKIRT (Image Credit: Credit: Joint Astronomy Centre; image processing by C. Davis, W. Varricatt.)