Space & astronomy · the experiment
Unmask the interstellar dust
A comet from another planetary system, the Webb telescope, a smooth bump near 10 micrometres. Four questions, from beginner to expert, on dust that has hardly ever been heated.
1 · Read the 10-micrometre bump
Beginner
According to Webb's spectrum, what kind of silicates does the dust of 3I/ATLAS contain?
2 · Work out the share of olivine
In the fit to the spectrum, amorphous pyroxene wins over amorphous olivine by about 180 to 1.
Intermediate
In those proportions, what share of the amorphous silicates is olivine?
3 · Explain why this dust is fresh
Cosmic rays can, in principle, turn crystals into glass, but only in the outer layers of a body. Webb observed 3I/ATLAS after its closest approach to the Sun.
Expert
Why do the authors consider this dust closer to the original composition?
4 · Compare the two ceilings
Here, the upper limit on crystalline silicates is 5.3% of the silicate emission. Another team, using a different Webb mode, puts it at 3.1% by mass.
Expert
Do these two figures contradict each other?
Dust unmasked
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