Scientists have long said that it is an unusually quiet galactic center, but the lack of energy seems to be temporary...

In other galaxies it is common to find black holes that are 100 million times brighter... Only 350 years ago it would have looked a million times brighter to us on Earth than it does now... Luckily, even if the black hole erupted again it would not pose a threat to life on Earthm, as our atmosphere provides ample protection from gamma rays.

But, the New Scientist article fails to mention if our atmosphere is enough to protect us from a million times current brightness (as in 350 years ago) or 100 million times, like other balck holes normally have, or even more than that...

Source: New Scientist Feb 5 2005, page 8