Fluffy ice that could help create the molecular building blocks for life has been spotted in space for the first time, nearly 30 years since researchers first observed it in the lab.
Normally, ice has a solid crystal lattice structure, with all of its H2O molecules strongly held together via their hydrogen and oxygen atoms. But when ice isn鈥檛 fully compacted, such as in powdery snow, some of these molecules can have loose ends, so that only one of their hydrogen atoms is bound up in the lattice while the other dangles out.
These so-called dangling bonds produce very specific signatures of light that scientists have measured in the laboratory. But finding these same signatures in space, such as from the ice-covered dust grains that go on to form stars and planets, has proven tricky, as Earth鈥檚 atmosphere absorbs these light frequencies.
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Now, at Aix-Marseille University in France and her colleagues have used the James Webb Space Telescope to spot the light from dangling bonds in a vast star-forming region around 500 light years away from Earth, known as the Chamaeleon I cloud.
Noble and her colleagues trained JWST鈥檚 sensitive infrared spectrometer on a large region of Chamaeleon I and found two frequencies that were almost exactly the same as what was seen in the lab, just slightly higher. One of them appears to be from light reflected by ice with dangling bonds, while the other appears to be from ice that has bonded to other molecules such as carbon monoxide.
Finding exactly what form the ice has taken is tricky, says Noble, as there are several different scenarios that could produce the signatures, and disentangling them will require more examples. 鈥淣ow that we can see them in space, we can start to look at how these modes differ from one environment to another,鈥� she says.
Once we can clearly tell the difference between the ice signatures, we will be able to understand how the icy rocks smash and clump together over time, a key mechanism for planet formation, says Noble.
at Heriot-Watt University, UK, who helped first measure dangling bonds in the lab nearly 30 years ago, says it is exciting to finally observe them in space. The interactions between light and ice dictate which molecules are made as planets form, he says, making understanding these bonds crucial to learning about the chemistry that led to life on Earth. 鈥淭hese little icy snowballs are essentially the chemical nanofactories in which complex organic molecules can be made.鈥�
Nature Astronomy
