The word “exoplanet” is foreign to most non-astronomers reading that name. Exoplanet is simply any planet not in this solar system. Do any exoplanets have similar characteristics to earth? Are any in that “goldilocks zone,” which give the capability of harboring life as we know it? Can we even see it, given its immense distance?
The “goldilocks zone” [Habitable zone – Wikipedia, the free encyclopedia] is considered a habitable area just far enough away from its sun, where life can be warm enough to flourish, but not too cold to freeze water. That means the temperature has to be between 32- 212o Fahrenheit, at which water exists in the liquid state.
Astronomer Michael Hart’s computer simulations are quite telling. For a habitable planet in the “goldilocks zone,” its orbit must be almost circular, and must make the right sized orbit. Calculations indicate a 5% smaller orbit point to a runaway “greenhouse effect,” or a 1% larger orbit would have resulted in a glacier effect-the freezing of all oceans.
The solar system must be free of large planets with elliptical orbits, which would eject or destroy other planets. Large planets with circular orbits are needed to clear out rogue asteroids that would strike inner planets much more frequently.
A planet that could be inhabited has to be large enough to hold an atmosphere, while small enough so its gravity doesn’t crush inhabitants. In addition, a planet must have a moderate temperature. A planet must have a mass in between 0.85 and 1.33 of earth’s mass, or within 2 billion years temperature variations would render the planet uninhabitable? [Extraterrestrials, Where Are They?, Second Edition, Edited by Ben Zuckerman and Michael Hart (Cambridge, England: Cambridge University Press, 1995), p. 217].
More importantly, a habitable planet must have some mechanism to keep CO2 from disappearing from the atmosphere. Liquid water begins a chain reaction depleting the atmosphere of CO2 [Ron Cohen, “Interplanetary Odyssey,” Science News (September 28th, 1996), p. 205].
Parts of earth’s surface continually sink where carbonate decomposes to CO2. It then recycles to the surface from volcanic activity, where it refills the atmosphere. We haven’t observed any other planet with similar tectonic activity.
Most extrasolar planets are too distant to detect their weather. Scientists utilize temperature variations over the surface of the giant gas planet [HD 189733b] revealing it’s likely whipped by savage winds. Scientists believe those winds are probably spreading the heat from its permanently sunlit side around to its dark side, where they might scream across the surface up to 6,000 mph.
Because exoplanets are invisible to the telescope “eye,” any atmosphere is examined by its infrared light, or heat. Infrared measurements from a quarter-million data points are used to map the temperature of the entire surface. The *Spitzer Space Telescope* is used with its extremely high infrared sensitivity.
But an observable exoplanet has got to be a *transiting* planet-it has to cross directly in front and behind its star when viewed from Earth. As an extrasolar planet passes in front of its star, it blocks out a small fraction of the star’s light, and a host of information about the exoplanet can be learned: size, temperature, orbit, and etcetera. Billions of exoplanets cannot be detected yet because the orbit of a host star may not be positioned correctly.
Over 300 extrasolar planets have been located and measured by this method, and are called “hot Jupiters” for a reason. Jupiter has many characteristics similar to exoplanets. It is a gas giant, with gas found down many miles to a hard surface.
The Coriolis Effect causes cyclones and anti-cyclones on Earth. Greatly magnified on Jupiter, these cyclones have a revolution 2.5x faster than Earth. Sheer distance makes cyclones on any exoplanets invisible.
Jupiter has many atmospheric disturbances, with stronger ones absorbing the weaker ones. This may explain the size of the largest spot on Jupiter-the Great Red Spot (GRS). Man has observed this spot for almost 400 years, or as long as the telescope existed. Over two earths would fit within this storm.
The GRS is anti-cyclonic in Jupiter’s southern hemisphere, and high pressure. It seems to be about 5 miles higher than other cloud tops. A hurricane on earth rotates clockwise, being low pressure. GRS however, has been shrinking at 230 miles/yr.
But at half the size of the GRS, Jupiter also has the “Oval BA,” which appeared in 2000. This was the result of three smaller spots merging. Scientists determined the Oval BA has winds up to 384 miles per hour. They believe environmental conditions, and dredging material close to the surface, turns red by UV light when brought to the top of the storm.
A much smaller red spot (Little Red Spot [LRS]) seen in the below picture, has merged with other storms. After 70 years, it was decimated by other merges, and by 2000 became non-existent as a third red spot.
[Image: See Explanation. Clicking on the picture will download the highest resolution version available.
Jupiter’s Three Red Spots (5/23/08)
*Credit NASA, ESA, M. Wong, I. de Pater (UC Berkeley), et al.
All three spots are in this image made on 5/9/98 (Hubble Space Telescope). Jupiter’s formation of spots is probably indicative of large scale climate change. It is getting warmer near the equator. The GRS is also warmer. “Warm,” in this case, translates to -250 oF. Surrounding temperatures are colder at -256 oF. Even that difference generates questions concerning global warming. Changes in Jupiter’s weather give rise to debate over perceived climate change on earth.
In 1998, scientists decided to launch an atmospheric probe into Jupiter. It finally crumpled to 23x higher pressure than earth’s atmosphere.
On Earth, anticyclones usually indicate fair weather. Jupiter’s anticyclones are also high pressure centers, while cyclones are low pressure. Jupiter is shrinking in size due to gravity. Actually a heat source, it radiates 1.6x more energy than it receives from the Sun.
Juno launched from Cape Canaveral on 8/5/2011, to begin its five-year journey to Jupiter. In 2016, many questions will be answered from Juno’s Jupiter encounter.
Is climate change a normal result of CO2 activity on Jupiter? Obviously not because of CO2, with almost “zero” content. Runaway “greenhouse effects” can occur with a 5% smaller orbit in a “goldilocks zone” but it’s never due to CO2. It’s always due to distance from the host sun.
One almost has to be an [exo-atmospheric meteorologist] to study this kind of weather. Stay tuned, because the science has changed since this was last printed.