Although there is absolutely no chance that the 500 meter diameter NEO asteroid 2003 UV11 will hit the earth (the asteroid is now inside the Earth's orbit and on its way Venus), just for a hoot I ran it through the Earth Impacts Program online calculator for effects at 100km distant from the point of impact. While this asteroid has a period of about 625 days, it will not be this close to the earth again until after 2170. Clear Skies - Kurt ----------------- Earth Impacts Effect Calculator http://impact.ese.ic.ac.uk/ImpactEffects/ Your Inputs: Distance from Impact: 100.00 km ( = 62.10 miles ) Projectile diameter: 500.00 meters ( = 1640.00 feet ) Projectile Density: 1500 kg/m3 Impact Velocity: 20.00 km per second ( = 12.40 miles per second ) Impact Angle: 45 degrees Target Density: 2500 kg/m3 Target Type: Sedimentary Rock Energy: Energy before atmospheric entry: 1.96 x 1019 Joules = 4.69 x 103 MegaTons TNT The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 1.1 x 105years Major Global Changes: The Earth is not strongly disturbed by the impact and loses negligible mass. The impact does not make a noticeable change in the tilt of Earth's axis (< 5 hundreths of a degree). The impact does not shift the Earth's orbit noticeably. Atmospheric Entry: The projectile begins to breakup at an altitude of 75100 meters = 246000 ft The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 19 km/s = 11.8 miles/s The impact energy is 1.77 x 1019 Joules = 4.22 x 103MegaTons. The broken projectile fragments strike the ground in an ellipse of dimension 1.36 km by 0.959 km Crater Dimensions: What does this mean? Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed. Transient Crater Diameter: 5.13 km ( = 3.19 miles ) Transient Crater Depth: 1.81 km ( = 1.13 miles ) Final Crater Diameter: 6.39 km ( = 3.97 miles ) Final Crater Depth: 517 meters ( = 1700 feet ) The crater formed is a complex crater. The volume of the target melted or vaporized is 0.111 km3 = 0.0267 miles3 Roughly half the melt remains in the crater, where its average thickness is 5.37 meters ( = 17.6 feet ). Thermal Radiation: What does this mean? Time for maximum radiation: 275 milliseconds after impact Visible fireball radius: 4.42 km ( = 2.75 miles ) The fireball appears 10.1 times larger than the sun Thermal Exposure: 6.82 x 105 Joules/m2 Duration of Irradiation: 1.13 minutes Radiant flux (relative to the sun): 10.1 Effects of Thermal Radiation: Much of the body suffers first degree burns Seismic Effects: What does this mean? The major seismic shaking will arrive approximately 20 seconds after impact. Richter Scale Magnitude: 7.0 Mercalli Scale Intensity at a distance of 100 km: VI. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight. VII. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken. Ejecta: What does this mean? The ejecta will arrive approximately 2.4 minutes after the impact. At your position there is a fine dusting of ejecta with occasional larger fragments Average Ejecta Thickness: 6.2 mm ( = 2.44 tenths of an inch ) Mean Fragment Diameter: 3.98 cm ( = 1.57 inches ) Air Blast: What does this mean? The air blast will arrive approximately 5.05 minutes after impact. Peak Overpressure: 18600 Pa = 0.186 bars = 2.65 psi Max wind velocity: 40.8 m/s = 91.2 mph Sound Intensity: 85 dB (Loud as heavy traffic) Damage Description: Glass windows will shatter. About 30 percent of trees blown down; remainder have some branches and leaves blown off.