Washington, January 23: Scientists say the sun that threatens the safety of multi-million dollar satellite systems has the wonderful side effect of helping mankind with an increasingly pressing problem: the specter of space junk.
Ever since mankind launched the first rocket into space, we''ve left trash floating aimlessly in low-Earth orbit. Today, 55 years after the launch of the Soviet Sputnik 1 (the worlds first artificial satellite), we are fast approaching an untenable situation.
The space junk problem is reaching epidemic proportions where it may soon become impossible to launch spacecraft without them being damaged or destroyed by an errant chunk of Space Age trash -- a situation known as “Kessler Syndrome.”
But a report (PDF) released by the NASA Orbital Debris Program Office this week suggested that solar activity might be able to help alleviate the space debris issue.
“Although high levels of solar activity are a bane to spacecraft operators, the consequent increase in the density of the Earth''s atmosphere is a welcome, albeit brief, respite from an otherwise growing orbital debris population,” the Discovery news quoted Nicholas Johnson, NASA Chief Scientist for Orbital Debris, as saying.
They say solar activity may be helping to “scrub” space trash from orbit.
During periods of increased solar activity -- like now -- the sun turns into a passive vacuum cleaner of sorts.
As magnetic activity inside the sun amps-up toward peak activity in its 11-year solar cycle (known as solar maximum, predicted to occur in 2013), there is a higher frequency of solar flares and coronal mass ejections (CMEs). This increased energy output energizes the outer layers of the Earth''s atmosphere, and through the laws of basic thermodynamics, it causes the atmosphere to expand.
This expansion pushes some of the gas to higher altitudes. Back in orbit, this tenuous gas creates drag on orbiting space debris, causing it to slow down.
As the debris slows, Earth’s gravity pulls it to lower altitudes where the atmosphere is even thicker. Thicker atmosphere = more drag = slower debris. Eventually the debris reenters the atmosphere sooner than it would do without the solar influence, burning up safely (for the most part).
“The number of cataloged debris in Earth orbit actually decreased during 2011 as solar activity increased toward an anticipated maximum in 2013,” adds Johnson.
“Smaller, uncataloged debris are even more affected by the changing atmosphere, causing even greater of their numbers to fall back to Earth,” he explained.
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