For quite some time now, scientists have noticed that sulfur is somehow strangely distributed throughout the Universe, and in some places it is clearly lacking. However, they have recently been able to solve this mystery.

Sulfur in space
An international team of scientists has recently shown in laboratory experiments that sulfur in space can form compounds that can stick to space dust and thus hide from spectroscopic studies. The results are published in the journal Astronomy & Astrophysics.
The fact that there is something wrong with the sulfur in the Universe has been noticed by scientists for quite some time. Studies show that where gas and dust form dense star-forming regions, it is clearly lacking. But where the density of the medium is much lower, it’s normal.
And recently, the MIRI infrared instrument on the James Webb Space Telescope presented scientists with a new mystery that, at first glance, has nothing to do with sulfur. Spectrograms of the very stellar cradles that lack this element show a mysterious bright peak. In a new study, scientists have found that there is, in fact, a connection.
How does sulfur disappear?
To understand what’s really going on there, scientists simulated the conditions of a gas-dust cloud in the laboratory. They had samples consisting of small silicate grains and ice. They were placed in a chamber with a very rarefied atmosphere that simulated the composition of a gas-dust nebula, and began exposing them to radiation similar to starlight.
Experiments have shown that volatile NH3 (ammonia) and volatile H2S (hydrogen sulfide, responsible for the smell of rotten eggs) react rapidly to form NH4SH (ammonium hydrosulfide salt). And this substance sticks to the surface of the hard grains. Spectroscopy sees the amount of this element in the free state decrease.
That is, the sulfur was not seen because it was incorporated into another compound. And scientists had only one thing to do: to check the spectrogram of NH4SH and see on it the very peak, which could not be explained.
What’s most interesting is that the scientists actually expected exactly this result. The fact that it could be ammonium hydrosulfide was speculated back in 2014-2016. Then the Rosetta spacecraft explored the comet Churiumov-Herasymenko and found that there was a lot of this substance there.
According to phys.org