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NOTE: This gallery was originally posted on June 28, 2011 and was updated on Nov. 8, 2011
NASA warns that an asteroid named 2005 YU55 which is about the size of an aircraft carrier will safely fly past the Earth, closer than the moon's orbit. The closest the asteroid is expected to approach the Earth is 201,700 miles or 0.85 the distance to the moon. This is expected to occur at 3:28 p.m. PST on Nov. 8.
The last time an asteroid flew this close to Earth was in 1976 - although it went unnoticed at the time. The next close encounter with an asteroid this size is expected in 2028.
This image of 2005YU was taken on Nov. 7 about 860,000 miles from Earth.
This map shows the 2005YU's nearest approch to Earth.
2005YU is near its closest approach to the moon.
The more you study solar flares and asteroids, the more you want to run for cover. But the real threat isn't to human life, it's to our energy infrastucture and communications.
NASA scientists are predicting a below average solar cycle beginning in 2011, similiar to the one that existed in 1859 when massive solar storms sent a flare that lit up the skies and set fire to some telegraph offices - the communications system at the time. Imagine the problems if that happened now. Plus, an asteroid passed within 7,500 miles of the Earth - today.
Officials met last week at the Space Weather Enterprise Forum to keep the world aware and begin to prepare for similar storms and flares that would have a major impact on the Earth's technology - GPS, satellites, power grids - and even your cell phone. There's a much bigger threat to our technology than to you.
Right now, we're virtually defenseless to a solar flare but NASA scientists are proposing a string of satellites around the sun that could see a major eruption and predict its path. Also under consideration are plans to shut down electrical grids if a potential threat occurs.
In this gallery we'll look at some real solar flares and daily space weather tracking - including today's close encounter with an asteroid.
Credit: NASA/Martin Stojanovski
Here's the size of the Earth compared to a normal solar flare that occured in March 2010. Fortunately, we're 93 million miles away from the sun so the odds are very much in our favor.
The 1859 super flare is called the "Carrington event" after English astronomer Richard Carrington who was studying sunspots when "blinding white light" suddenly appeared over them in a kidney shape. See his diagram above.
The next day, telegraph offices reported sparks flying that caused some fires, and in some places electrical currents kept the equipment operating even after the batteries were disconnected. Auroras could be seen all over the planet, even in tropical latitudes such as Hawaii. Some were so bright that newspapers could be read at night.
Solar flares are a very common occurance. This one in 2006 damaged the X-ray Imager, which took this image, onboard NOAA's GOES-13 satellite. The Carrington event was most likely much brighter.
In 1989 a solar flare caused geomagnetic storms that shut down the power system in Quebec for 9 hours.
This amazing aurora in early June was a byproduct of the solar flare seen in the previous image.
Here's a solar flare from February 2011.
This solar flare is from December 2010.
Should a solar flare hit Earth directly, astronauts and satellites will be completely exposed. Their only hope is that they will be on the other side of the planet when it hits.
Both NASA and the National Oceanic and Atomspheric Administration (NOAA) operate sites that track space weather. Here is an image from the sun on June 27 that shows a "coronal hole." A solar wind from this hole should reach Earth on July 1 or July 2.
There is only one sunspot right now with no threat of a solar flare according to NASA.
Imagine my surprise upon visiting NASA's spaceweather .com, when I read that asteroid 2011MD was going to fly by the Earth within an hour. Upon further review, it is only about 10 meters wide and should pass about 7,500 miles away - actually not that far. If you're reading this, we must be OK.
This asteroid is just one of 1,237 potentially hazardous space rocks being tracked. The miss distance is tracked by LD which is the distance from the Earth to the moon. 2011 MD came within 0.05 LDs of the Earth. From that perspective, wow.
The space weather forecast for June 27 from the NOAA Space Weather Prediction Center.
Here's a chart of sunspots over the past few years. There actually have been many less than usual.
Xrays from space are tracked on a continual basis.