The star-forming galaxy is known as A1689-zD1, and provides clues as to the formation of our own solar system. Astronomers now speculate that the space dust from which we are all made could have accumulated much earlier than previously thought, writes Amina Khan of the Los Angeles Times.
A1689-zD1: Extremely distant galaxy
The study of extremely far away space objects allows scientists to look back in time. If you take a photo of the sun from Earth, the picture actually shows the sun as it was 8 minutes ago because it takes that amount of time for light from the sun to reach Earth. By observing a galaxy that is billions and billions of light-years distant, we actually see how it was billions of years ago.
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The issue with these extremely distant objects is that they are hard to observe because they are very faint, which makes seeing back into the early stages of the universe’s 13.8-billion-year history a tough proposition. Fortunately A1689-zD1 was picked up by astronomers because the light that it emits is being bent by a massive galaxy cluster known as Abell 1689.
Not only does Abell 1689 bend the galaxy’s faint light, it also amplifies it, making A1689-zD1 appear 9.3 times as bright as normal. The study of extremely distant objects is aided enormously by this phenomenon, which is known as gravitational lensing.
Why so much dust?
The galaxy was forming the equivalent of 12 suns’ worth of new stars every year, but the scientists were surprised by quite how much dust A1689-zD1 contained. Its dust-to-gas ratio is “close to that of the Milky Way,” wrote the authors of the study.
Previous models suggested that early galaxies did not contain much dust because of the lengthy process of forming heavy elements through the birth and death of generations of stars. It is surprising to see such an early galaxy contain such a large amount of dust.
The study suggests that “evolved” galaxies appeared far earlier than previously thought.
“Although the exact origin of galactic dust remains obscure, our findings indicate that its production occurs very rapidly, within only 500 million years of the beginning of star formation in the universe — a very short cosmological time frame, given that most stars live for billions of years,” said lead author Darach Watson.