It was from this morning, about 6 hours ago. I think Mylan posted it.<quoted text>
The other black hole, GRS 1915+105, is estimated to be about 14 times the Sun's mass, which is nearing the upper limit for a black hole formed from the collapse of a single star. Using NASA's Rossi X-ray Timing Explorer (RXTE), astronomers were able to determine that IGR J17091-3624 was much, much smaller. In fact, it's probably only three times as massive as the Sun, which is dangerously close to the minimum amount of mass needed to create a black hole in the first place.
The former (GRS 1915+105 ) is stated as an UPPER LIMIT for a black hole formed from the collapse of a SINGLE STAR.
The latter ( IGR J17091-3624) speaks to MINIMUM limits (for formation from stellar collapse).
Both speak of limits for *formation* of black holes, via a specific mechanism.
Where are you getting mass of a mountain from? What article?