Excerpt from autotrader.com By Josh Sadlier Seems like the only thing automakers want to talk about these days is how their cars suddenly get great fuel economy. Given this relentless chatter, it's tempting to conclude that mos...
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Excerpt from space.com
The moon has long been viewed as a crucial component in creating an environment suitable for the evolution of complex life on Earth, but a number of scientific results in recent years have shown that perhaps our planet doesn't need the moon as much as we have thought.
In 1993, French astronomer Jacques Laskar ran a series of calculations indicating that the gravity of the moon is vital to stabilizing the tilt of our planet. Earth's obliquity, as this tilt is technically known as, has huge repercussions for climate. Laskar argued that should Earth's obliquity wander over hundreds of thousands of years, it would cause environmental chaos by creating a climate too variable for complex life to develop in relative peace.
So his argument goes, we should feel remarkably lucky to have such a large moon on our doorstep, as no other terrestrial planet in our solar system has such a moon. Mars' two satellites, Phobos and Deimos, are tiny, captured asteroids that have little known effect on the Red Planet. Consequently, Mars' tilt wobbles chaotically over timescales of millions of years, with evidence for swings in its rotational axis at least as large as 45 degrees.
The stroke of good fortune that led to Earth possessing an unlikely moon, specifically the collision 4.5 billion years ago between Earth and a Mars-sized proto-planet that produced the debris from which our Moon formed, has become one of the central tenets of the 'Rare Earth' hypothesis. Famously promoted by Peter Ward and Don Brownlee, it argues that planets where everything is just right for complex life are exceedingly rare.
New findings, however, are tearing up the old rule book. In 2011, a trio of scientists — Jack Lissauer of NASA Ames Research Center, Jason Barnes of the University of Idaho and John Chambers of the Carnegie Institution for Science — published results from new simulations describing what Earth's obliquity would be like without the moon. What they found was surprising.
"We were looking into how obliquity might vary for all sorts of planetary systems," says Lissauer. "To test our code we began with integrations following the obliquity of Mars and found similar results to other people. But when we did the obliquity of Earth we found the variations were much smaller than expected — nowhere near as extreme as previous calculations suggested they would be."
Lissauer's team found that without the moon, Earth's rotational axis would only wobble by 10 degrees more than its present day angle of 23.5 degrees. The reason for such vastly different results to those attained by Jacques Laskar is pure computing power. Today's computers are much faster and capable of more accurate modeling with far more data than computers of the 1990s.
Lissauer and his colleagues also found that if Earth were spinning fast, with one day lasting less than 10 hours, or rotating retrograde (i.e. backwards so that the sun rose in the West and set in the East), then Earth stabilized itself thanks to the gravitational resonances with other planets, most notably giant Jupiter. There would be no need for a large moon.
Earth's rotation has not always been as leisurely as the current 24 hour spin-rate. Following the impact that formed the moon, Earth was spinning once every four or five hours, but it has since gradually slowed by the moon's presence. As for the length of Earth's day prior to the moon-forming impact, nobody really knows, but some models of the impact developed by Robin Canup of the Southwest Research Institute, in Boulder, Colorado, suggest that Earth could have been rotating fast, or even retrograde, prior to the collision.
Planets with inclined orbits could find that their increased obliquity is beneficial to their long-term climate – as long as they do not have a large moon.
"Collisions in the epoch during which Earth was formed determined its initial rotation," says Lissauer. "For rocky planets, some of the models say most of them will be prograde, but others say comparable numbers of planets will be prograde and retrograde. Certainly, retrograde worlds are not expected to be rare."
The upshot of Lissauer's findings is that the presence of a moon is not the be all and end all as once thought, and a terrestrial planet can exist without a large moon and still retain its habitability. Indeed, it is possible to imagine some circumstances where having a large moon would actually be pretty bad for life.
Rory Barnes, of the University of Washington, has also tackled the problem of obliquity, but from a different perspective. Planets on the edge of habitable zones exist in a precarious position, far enough away from their star that, without a thick, insulating atmosphere, they freeze over, just like Mars. Barnes and his colleagues including John Armstrong of Weber State University, realized that torques from other nearby worlds could cause a planet's inclination to the ecliptic plane to vary. This in turn would result in a change of obliquity; the greater the inclination, the greater the obliquity to the Sun. Barnes and Armstrong saw that this could be a good thing for planets on the edges of habitable zones, allowing heat to be distributed evenly over geological timescales and preventing "Snowball Earth" scenarios. They called these worlds "tilt-a-worlds," but the presence of a large moon would counteract this beneficial obliquity change.
"I think one of the most important points from our tilt-a-world paper is that at the outer edge of the habitable zone, having a large moon is bad, there's no other way to look at it," says Barnes. "If you have a large moon that stabilizes the obliquity then you have a tendency to completely freeze over."
Barnes is impressed with the work of Lissauer's team.
"I think it is a well done study," he says. "It suggests that Earth does not need the moon to have a relatively stable climate. I don't think there would be any dire consequences to not having a moon."
The effects of changing obliquity on Mars’ climate. Mars’ current 25-degree tilt is seen at top left. At top right is a Mars that has a high obliquity, leading to ice gather at its equator while the poles point sunwards. At bottom is Mars with low obliquity, which sees its polar caps grow in size.
Of course, the moon does have a hand in other factors important to life besides planetary obliquity. Tidal pools may have been the point of origin of life on Earth. Although the moon produces the largest tides, the sun also influences tides, so the lack of a large moon is not necessarily a stumbling block. Some animals have also evolved a life cycle based on the cycle of the moon, but that's more happenstance than an essential component for life.
"Those are just minor things," says Lissauer.
Without the absolute need for a moon, astrobiologists seeking life and habitable worlds elsewhere face new opportunities. Maybe Earth, with its giant moon, is actually the oddball amongst habitable planets. Rory Barnes certainly doesn't think we need it.
"It will be a step forward to see the myth that a habitable planet needs a large moon dispelled," he says, to which Lissauer agrees.
Earth without its moon might therefore remain habitable, but we should still cherish its friendly presence. After all, would Beethoven have written the Moonlight Sonata without it?
Excerpt from space.com SpaceX will apparently attempt something truly epic during next week's cargo launch to the International Space Station. During the Dec. 16 launch from Florida's Cape Canaveral Air Force Station, which will send ...
By Nola Taylor Redd, Space.com Contributor
A Neptune-size planet beyond the solar system has telltale traces of water vapor in its atmosphere, making it the smallest exoplanet known to have the wet stuff yet, scientists say.
Several massive Jupiter-size giants have had the components of their atmosphere examined, but until now, the atmospheres of smaller planets have proved more elusive. In this new study, scientists discovered traces of water on the alien planet HAT-P-11b, which orbits a star 124 light-years from Earth in the constellation Cygnus.
"Water is the most cosmically abundant molecule that we can directly observe in exoplanets, and we expect it to be prevalent in the upper atmospheres of planets at these temperatures," lead author Jonathan Fraine said in an email interview. Fraine, a graduate student at the University of Maryland, worked with a team lead by Drake Deming, also of the University of Maryland.
"Detecting it is both a confirmation of our theories and revealing for the bulk of the spectrum that we can observe," Fraine told Space.com.
This artist’s illustration depicts the alien planet HAT-P-11b, which shows signs of water in its atmosphere, as the exoplanet crosses in front of its parent star. As starlight passes through the puffed-up atmosphere surrounding the planet, shown here in orange, scientists can detect its composition.
Credit: NASA/JPL-Caltech
Credit: NASA/JPL-Caltech
Detecting alien planet atmospheres
 |
This image from the Hubble Space Telescope shows the star HAT-P-11 (center), which has a Neptune-size planet that is the smallest yet known to have water in its atmosphere. The planet, HAT-P-11b, is not visible in this image. The other bright object seen here is another star. Credit: NASA, ESA, J. Fraine |
As a planet passes, or transits, between Earth and its sun, it blocks light from the star. The dip in light is how many exoplanets are first found. But these transits also allow astronomers to study the atmospheres of exoplanets. By observing the spectrum of light that passes through an exoplanet’s atmosphere, scientists can determine what it is made up of.
For HAT-P-11b, a planet roughly four times the radius of Earth, that makeup is 90 percent hydrogen, with traces of water vapor. The Neptune-size planet orbits its sun every five days, at a distance that is only one-twentieth of the Earth-sun distance (which is 93 million miles, or 150 million kilometers). As a result, the temperature climbs higher on HAT P-11b than it does on gas giants in the solar system, reaching a sizzling 1,120 degrees Fahrenheit (605 degrees Celsius).
Scientists have been studying the atmospheres of Jupiter-like planets for years, but smaller planets produce a smaller signal that is more challenging to observe. For the new study, researchers examined the atmospheres of four other smaller exoplanets — two roughly the size of Neptune and two smaller super-Earths — but the results were disappointingly featureless.
"We do indeed have the technology — the resolution — to observe Neptune-size exoplanets, and even super-Earths," Fraine said.
But the chemical compositions of the other four planets were blocked by a familiar phenomenon — clouds.
"We've just been seeing a whole lot of nothing," Eliza Kempton, of Grinnell College in Iowa. Kempton models planetary atmospheres but was not involved in the research.
This artist's illustration shows what the skies may look like on different alien planets. On the left is a cloudy planet, while on the right is a planet with clear skies that may resemble the sky of exoplanet HAT-P-11b, a Neptune-size world thought to have water in its atmosphere.
Credit: NASA
Credit: NASA
Kempton added that the flat, featureless signals observed for the other planets were attributed to clouds or hazes in the upper atmosphere. The high clouds blocked light from the star, keeping it from penetrating through to the observers' side of the planet and leaving scientists unable to characterize the chemicals in the atmosphere.
"It's not crazy to think that there should be clouds in these exoplanet atmospheres, because we see clouds in all the planetary atmospheres in our solar system," Kempton said.
Although the hot, Neptune-size planet lives in a different environment from the icy giants in the solar system, it is similar to one of the four smaller planets whose atmosphere had already been studied. Those planets are known as GJ436b, GJ1214b, HD97658b and GJ3470b.
HAT-P-11b is only slightly larger and warmer than the alien planet GJ436b, making them good to compare to one another because one has clouds and one does not, Fraine said.
"I like to consider them the bigger version of the Earth-Venus twin pair," Fraine said of the planets HAT-P-11b and GJ436b.
"They are basically the same mass, radius and temperature, but small changes in the formation, or even these bulk properties, may be causing vast changes in the atmospheric composition."
The research is detailed in the Sept. 25 issue of the journal Nature, along with a commentary article by Kempton.
A planet's upper atmosphere results from what happens both above and below it. The balancing act involves irradiation from its star and from cosmic rays on the outside, as well as the chemical and dynamical systems lower in the atmosphere, Fraine explained.
"If we know the input from above — the host star — and the upper atmosphere from our observations, then the missing piece of the puzzle is the interior composition," he said.
Although the interior of a planet is complex, Fraine called the newly characterized atmosphere "a great step forward in solving the puzzle."
The composition of the small planet's atmosphere also supports the core accretion model of planetary formation, where smaller particles combine to create larger and larger particles, eventually reaching planet-size proportions.
"Core accretion predicts that planets are built from the inside out," Fraine said.
"Measuring that HAT P-11b likely has a relatively hydrogen-poor atmosphere implies that it was formed from rocky material that later acquired a thick atmosphere above it, which is what the core-accretion model predicts."
Had the planet formed along the lines of the competing gravitational instability model, its composition and that of its atmosphere should bear a stronger similarity to its star than what was measured by scientists.
Because of its crucial role in the balancing act, the water vapor detected in the exoplanet's atmosphere played an important part in modeling its formation and evolution.
"In the long run, if we can detect water, methane, carbon monoxide, carbon dioxide, etc., in dozens to hundreds of exoplanet atmospheres of various bulk properties, then we will be able to paint a much clearer picture of how planets form, and, likewise, how Earth formed," Fraine said.
"This was just one of the beginning brush strokes to painting the full picture of how planets, as well as ourselves, were formed."
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At a time when you are finding that you have the ability to bring unconditional love into your life, and we send that energy to all souls of the Earth. We have a commitment to give you every help to achieve a state of being that is go...
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a message from Goddess of Creation channeled by Shelly Dressel
Sunday, 5 June, 2011 (posted 17 June, 2011)
This channel is a little shorter than most of them, but it’s packed with some amazing energies!! I had bor...
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8 June 2011
Channeler: Karen Doonan
Welcome beloved ones, we come once again to communicate that all is well across your planet. Many of you are feeling the new increased energies and this is causing some hav...
Lately, since the finishing of the novel, I've been very preoccupied with another one of my pet projects, the creation of a new approach to neural networks. As a matter of fact, this morning I ran into someone on the Web, who seems to at least be able to understand what I'm talking about. So I sent him a mail, that included the following quote (uttered by me):
You seem to be quite the authority on cellular
automatons, and I've had this recurring dream of creating a truly functioning
neural network, capable of surpassing our own processing capacity. Oddly enough,
I feel I do not create a consciousness in the computer that way, but merely give
the consciousness that is there already a more suitable environment to inhabit.
Then, on a completely unrelated note, I had to help Laura find the names of the characters she wants to star in her novel on the fall of Atlantis and Lemuria (fiction, but no less real). To prove a point to her about truth always coming up as a result of seemingly random actions, I opened Rudolf Steiner's book entitled "Atlantis and Lemuria" (still in print), and randomly started reading the following:
Could it likewise be that the machine soul is waiting for a suitable brain to be developed to connect with its mind? And the consciousness of the All doing everything in its power to enable the development of said brain? Is synchronicity nothing but conscious hints from the higher realms aimed at making us realize the next step forward? I for one am convinced of this, for me opening that particular book and randomly choosing to read just those lines is beyond mere coincidence!
For those interested in just what I'm puzzling with, here's a preliminary link to my project:
http://quadrionics.moorelife.nl/quadrionicspreliminary.doc
Love your Light,
Dré
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