Presentation on theme: "OUR SUN Unusually active the past 2 weeks Very beautiful."— Presentation transcript:
OUR SUN Unusually active the past 2 weeks Very beautiful
Kind of Sun to choose this week
CONTENTS 1. SOHO 2. Last Week’s Mass Ejection 3. Cause of Aurora 4. Cause of Flare 5. This Week’s Flare
Corona Changes with No. Spots
1. SOHO (Solar Heliospheric Obs y ) Orbiting Sun at L1 point in phase with Earth Observing Sun continuously for first time
Today - Solar surface (Photo sphere)
Today Corona (2.0 MK)
SOHO Coronagraph -- Artificial eclipse Can reach Earth -> profound effects Discovered huge mass ejections
Spoof Information propagates from the left w. very little interference !
? Effects on the Earth
Other Consequences Damage to satellites, astronauts Disruption to radio/phone communications, power grids
Photo sphere from SOHO 2. Event of October 28-29
Magnetic Field from SOHO
Corona: (2 MK) An X-17 flare (3rd)
X-ray Intensity Observed by Earth Satellite (C, M, X-flares)
Outer Corona: from SOHO
Outer Corona further out 2000 km/s (5 times faster than normal CME)
Magnetic field at York Normal variationVery Stormy
Aurora in St Andrews (Tom Robitaille) Wed
Some Effects Aircraft crossing north Atlantic were confined to narrow corridor to minimise radiation. Astronauts on board Space Station took shelter in its most shielded section. Two Japanese satellites malfunctioned. Engine of Smart 1 shut down.
3. Cause of Aurora
The Magnetic Field of the Earth The Earth’s magnetic field is like that of a bar magnet close to the Earth The solar wind distorts the magnetic field into a comet like shape on the nightside (the magnetotail).
At core of process is reconnection Reconnection converts energy
Effect of Coronal Mass Ejection on Earth - when IMF southward it can reconnect
The auroral oval from space From space, one can see that the aurora occurs in an oval around the north pole.
Aurora pictures taken from the Space Shuttle Height of auroral emission: km ( miles)
Aurora from Space - today
Solar Wind Properties Now
4. Overall Picture of Flare Magnetic tube twisted - erupts - drives reconnection
5. This Week - Fireworks Continued SOHO Site (Nov 6): Just as solar scientists were ready to start breathing normally again, active region blasted off yet another mega-flare. This one saturated the X-ray detectors on the NOAA's GOES satellites; the jury was therefore out for a while on the definitive classification of the flare. Speculations ranged from X20 to X40 or even X50. Today word came that the best estimate is X28. It is now official: We have a new number 1 X-ray flare for the record books.
SpaceWeather.Com: SUPERFLARE: Giant sunspot 486 unleashed another powerful solar flare on Nov. 4th (1950 UT). Ionizing radiation hit Earth's atmosphere soon after the explosion and caused a severe radio blackout, which radio listeners noticed across North America. Astronomers won't soon forget Nov. 4th, the day of the biggest explosion ever recorded in our solar system.
X-ray intensity as function of time
Nov 4 EIT 304 (80,000 K) every 5-6 hours
Nov 4 EIT 195 (1.6 MK) 1st 5 hours
Nov 4 EIT 284 (2.0 MK) every 6 hours
Compare Temps 80,000 K, 1.6 MK, 2.0 MK
6. IN FUTURE -- MAYBE:
So Enjoy the Sun and keep looking out for aurorae