November 24, 2014

20.02.11: A Snapshot of a Primordial Galaxy.

A pale blue smudge…(Credit: NASA/ESA/Garth Illingworth (UC Santa Cruz)/Rychard Bouwens (UC Santa Cruz and Leiden University)/the HUDF09 Team).

When it comes to the Hubble Space Telescope, the hits just keep on a’ comin’… earlier this year, researchers pushed the refurbished telescope to its limits, revealing what may prove to be most distant galaxy (or indeed object) yet seen. At 13.2 light years distant, the smudge pictured above would have been from a time when the universe was only about 500 million years old. [Read more...]

03.06.10: Do “Dirty” White Dwarfs Provide a Key Spectral Signature?

 

White dwarf stars as seen by the Hubble Space Telescope dotting the globular cluster M4. (Credit: NASA/H. Richer).

White dwarf stars as seen by the Hubble Space Telescope dotting the globular cluster M4. (Credit: NASA/H. Richer).

 

   If astronomers at the Leicester University in the United Kingdom are correct, the key elements and chemicals that comprise life may be common throughout our Milky Way. The evidence comes from an unlikely source; spectral examinations of populations of galactic white dwarfs. These ancient remnants of stars exist in vast numbers, and our Sun will indeed share their fate one day. The study, led by researcher Jay Farihi, looked at over 100 million objects in the Sloan Digital Sky Survey, which provides a map of the sky and our galaxy as seen in the infrared spectrum. Their findings conclude that up to 20% of all white dwarfs surveyed are contaminated with trace metals, most likely the result of interplanetary debris. In the field of astronomy, the term “metal” refers to anything that isn’t hydrogen or helium, a little different definition than what you learned (hopefully) in high school chemistry. The thinking goes that where heavier elements are seen, terrestrial planets and perhaps life may be sure to follow. Our Sun itself is a good case in point; a Population I star that is relatively metal rich, allowing for a large retinue of rocky planets, including the Earth. How common or rare we are is still hotly debated, but this analysis of the atmospheres of white dwarfs may prove that terrestrial worlds are perhaps abundant throughout the cosmos.  In terms of this study, astronomers are in a sense looking at the “ruins” of older terrestrial systems that will be recycled and incorporated into new, metal dense populations… perhaps one could argue that as time in universe marches on and heavier elements become more abundant, the odds are that life will become more frequent, at least until the stelliferous era runs its course!