Dark Matter – made of lots of little black holes?
One of the perhaps least popular theories about the nature of dark matter is that it simply consists of lots of smallish primordial black holes – those that were created in the early stage of the universe, just within the first second or so after the big bang.
Now a publication has suggested that this theory could be tested – they estimate that the probability of such black holes passing through the inner solar system is in the region of once in a decade. Such a passage would give a tiny kick to the orbit of Mars – which would be measurable given that the orbit of Mars is known to a very high degree of accuracy. They will now trawl the data to look for such a deviation – but they will also have to rule out that the deviation was caused by an asteroid.
