Why Nebulae Fool Astronomers ⚡ экспресс
Scientists couldn't understand why different measurements of gas density in space produce wildly varying results. It turns out each method is sensitive only to gas of a particular density—like a sieve with different mesh sizes. In reality, gas is a mixture of regions with different densities, and there is no single overall density. This finding changes our usual estimates of the mass and other properties of galaxies. Could the Universe be denser than we thought?
Nebulae are glowing clouds of gas where stars are born. To measure their density, we break down light into colors using light decomposition. But for decades, different spectral lines showed values differing by hundreds of times. This isn't an error—it's a quirk of how nebulae are structured.
A nebula resembles a sponge with pores of varying sizes. It contains nearly empty cavities as big as the Solar System alongside microscopic clumps—future stars. Each measurement method acts like a sieve with a specific mesh size: one catches only diffuse gas, another only dense clumps. Hence the discrepancy in numbers.
Previously, astronomers calculated mass and chemistry using a single number. Now, these calculations must be revised—from nearby clouds of hydrogen to distant galaxies. Density variations within a single nebula can reach a million-fold: the densest clump has a density like air, even though the surroundings are a cosmic vacuum.
🎯 Even the most rarefied part of a nebula contains hundreds of times more atoms than the best vacuum we can create in Earthly labs.