The team even went crazy with a can of black spray paint, comparing the results to a Teflon surface.

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Blazars are a special case of "active galaxies" - those whose supermassive black holes spray out great quantities of light across the whole electromagnetic spectrum as they feed on surrounding matter.

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Two officers at first used CS spray to try to stop the fight at the Black Horse in Penycae, Wrexham.

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"That was the moment we said we can do more than just spray water on those things, " said Mr. Black.

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