Windy Friday
February 24th, 2012 at 12:58 pm by David Mazza under Weather
A strong cold front blasted through our area last night bringing temps down almost 30 degrees from yesterday. It should be noted our high temp yesterday was 25 degrees above normal, and today’s forecast high is 5 degrees below normal. Besides the much colder air, we also have had some strong winds today. The Wind Advisory from this morning has expired, but we could still see some wind gusts in excess of 30mph. On a day like today when the winds are stronger than normal, it is caused by areas of high pressure and low pressure being closer together than normal, and our backyards are the playground for the pressure. The air molecules from the high pressure center move away towards the center of the low pressure trying to equalize the overall pressure in the area. Another way of thinking of this, imagine you are on a bike and you do not want to peddle the wheels. So if you want to move from point a to b, again without having to do work, you would start on top of a hill (high pressure) and end at the bottom (low pressure). The closer together the top and bottom of the hill are, the faster you will travel (like faster winds). If the top and bottom of the hill are far apart, you will move slower.
If you thought the winds today were strong in our area, look at what the folks at NASA have found, a black hole with a wind speed that clocked in around 20 million miles per hour!!!!
(The image and the story come from the NASA website)
Chandra Finds Fastest Wind From Stellar-Mass Black Hole
This artist’s impression shows a binary system containing a stellar-mass black hole called IGR J17091-3624, or IGR J17091 for short. The strong gravity of the black hole, on the left, is pulling gas away from a companion star on the right. This gas forms a disk of hot gas around the black hole, and the wind is driven off this disk.
New observations with NASA’s Chandra X-ray Observatory clocked the fastest wind ever seen blowing off a disk around this stellar-mass black hole. Stellar-mass black holes are born when extremely massive stars collapse and typically weigh between five and 10 times the mass of the Sun.
The record-breaking wind is moving about twenty million miles per hour, or about three percent the speed of light. This is nearly ten times faster than had ever been seen from a stellar-mass black hole, and matches some of the fastest winds generated by supermassive black holes, objects millions or billions of times more massive.
Another unanticipated finding is that the wind, which comes from a disk of gas surrounding the black hole, may be carrying away much more material than the black hole is capturing.
The high speed for the wind was estimated from a spectrum made by Chandra in 2011. A spectrum shows how intense the X-rays are at different energies. Ions emit and absorb distinct features in spectra, which allow scientists to monitor them and their behavior. A Chandra spectrum of iron ions made two months earlier showed no evidence of the high-speed wind, meaning the wind likely turns on and off over time.
Image Credit: NASA/CXC/M.Weiss
