Showing posts with label european space agency. Show all posts

Thursday, 1 July 2010

Were Venus and Mars Once Habitable Planets?

And Did a Mega Collision Alter Venus?

The European Space Agency's Venus Express is helping planetary scientists investigate whether Venus once had oceans. If it did, it may even have begun its existence as a habitable planet similar to Earth.
These days, Earth and Venus seem completely different. Earth is a lush, clement world teeming with life, whilst Venus is hellish, its surface roasting at temperatures higher than those of a kitchen oven.
But underneath it all the two planets share a number of striking similarities. They are nearly identical in size and now, thanks to ESA's Venus Express orbiter, planetary scientists are seeing other similarities too.
"The basic composition of Venus and Earth is very similar," says Håkan Svedhem, ESA Venus Express Project Scientist. Just how similar planetary scientists from around the world will be discussing in Aussois, France, where they are gathering this week for a conference.
One difference stands out: Venus has very little water. Were the contents of Earth's oceans to be spread evenly across the world, they would create a layer 3 km deep. If you were to condense the amount of water vapour in Venus' atmosphere onto its surface, it would create a global puddle just 3 cm deep.
Yet there is another similarity here. Billions of years ago, Venus probably had much more water. Venus Express has certainly confirmed that the planet has lost a large quantity of water into space.
It happens because ultraviolet radiation from the Sun streams into Venus' atmosphere and breaks up the water molecules into atoms: two hydrogens and one oxygen. These then escape to space.
Venus Express has measured the rate of this escape and confirmed that roughly twice as much hydrogen is escaping as oxygen. It is therefore believed that water is the source of these escaping ions. It has also shown that a heavy form of hydrogen, called deuterium, is progressively enriched in the upper echelons of Venus's atmosphere, because the heavier hydrogen will find it less easy to escape the planet's grip.
"Everything points to there being large amounts of water on Venus in the past," says Colin Wilson, Oxford University, UK. But that does not necessarily mean there were oceans on the planet's surface.
Eric Chassefière, Université Paris-Sud, France, has developed a computer model that suggests the water was largely atmospheric and existed only during the very earliest times, when the surface of the planet was completely molten. As the water molecules were broken into atoms by sunlight and escaped into space, the subsequent drop in temperature probably triggered the solidification of the surface. In other words: no oceans.
Although it is difficult to test this hypothesis it is a key question. If Venus ever did possess surface water, the planet may possibly have had an early habitable phase.
Even if true, Chassefière's model does not preclude the chance that colliding comets brought additional water to Venus after the surface crystallised, and these created bodies of standing water in which life may have been able to form.
There are many open questions. "Much more extensive modelling of the magma ocean-atmosphere system and of its evolution is required to better understand the evolution of the young Venus," says Chassefière.
When creating those computer models, the data provided by Venus Express will prove crucial. #

Did A Mega-Collision Alter Venus?

A mega-collision between two large embryonic planets could have created Venus as we know it, according to a new paper by a Cardiff University scientist.
Venus is a sister planet to Earth. It is nearly the same size and density yet it has a surface temperature of 720 K, an atmosphere dominated by carbon dioxide and no evidence of oceans or ridges. It has been described as “Earth’s evil twin”.
Dr Huw Davies, of the School of Earth and Ocean Sciences argues that a mega-collision could explain these differences. In particular the collision could explain why the interior of Venus is dry, the odd rotation of the planet and the carbon dioxide atmosphere.
Dr Davies of the School of Earth and Ocean Sciences said: “A collision theory has been explored by scientists previously but was abandoned as the planet Venus has no moon usually expected from such an impact. However, a mega-impact could have created Venus, since the head-on collision I propose does not produce a moon.”
The hot ball of gas and liquid that would result immediately following the collision would allow iron to react away the water, leaving Venus a dry planet. Significant suggested consequences of a dry planet include the lack of plate tectonics, continents and life.
Dr Davies’ research is published in the journal Earth and Planetary Science Letters. *

Mars Was Wet, Globally

The picture of an ancient Mars that looked a lot more like Earth came into sharper focus with a new study showing that the planet’s northern regions apparently shared a proclivity for water.

Kudos to a team of French and American scientists who found the north’s first telltale clay mineral deposits, which form in water’s presence. Thousands of similar deposits have been found in the planet’s southern highlands... The detections by Europe’s Mars Express and NASA’s Mars Reconnaissance orbiters are the first time the minerals have been found in the north, which has younger surface rocks due to more recent volcanic activity.
Writing in this week’s Science, the researchers explain that the minerals were found in some large craters that had cut through the younger, overlying rocks. In nine of 91 craters scanned, clay-like minerals called phyllosilicates, which on Earth form in wet environments, were found. The discovery raises the prospect that early Mars had water on a global scale.^%

NASA report: Hydrated Minerals Exposed at Stokes, Northern Mars

Stokes Crater, pictured here, is one of at least nine craters in the northern lowlands of Mars with exposures of hydrated minerals detected from orbit, according to a June 25, 2010, report.

These minerals, including phyllosilicates, have previously been found in thousands of small outcrops in the southern highlands of Mars, but had not previously been identified in the northern lowlands, which cover nearly half of the planet. The numerous outcrops in the south have been interpreted as evidence that early Mars -- about 4 billion years ago -- had wet conditions necessary for producing phyllosilicates and possibly conducive to life.

The exposures in some northern craters indicate these minerals are in an older layer underneath the younger surface of northern Mars and are made visible where crater-forming impacts have exposed the underlying material. The new report in the journal Science by John Carter of the University of Paris and his co-authors says that the northern finds suggest the ancient, wet conditions extended globally. Their report draws upon observations by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard NASA's Mars Reconnaissance Orbiter and the OMEGA spectrometer orbiting aboard the European Space Agency's Mars Express.

Stokes spans 66 kilometers (41 miles) in diameter, centered at 55.6 degrees north latitude, 171.2 degrees east longitude.

The image on the right shows an area near the center of the crater, with color coding for where CRISM observations have shown exposures of three types of hydrated minerals and nearby exposures of two volcanic minerals unaltered by water: pyroxene and olivine. The scale bar is 2 kilometers (1.2 miles).

The context map on the left indicates the location of that CRISM footprint within Stokes Crater. It is a mosaic of images taken by the Context Camera on Mars Reconnaissance Orbiter and the High Resolution Stereo Camera on Mars Express. The scale bar is 25 kilometers (15.5 miles).

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the spacecraft. The Johns Hopkins University Applied Physics Laboratory led the effort to build the CRISM instrument and operates CRISM in coordination with an international team of researchers from universities, government and the private sector. Malin Space Science Systems, San Diego, provided and operates the Context Camera.

The European Space Operations Centre in Darmstadt, Germany, operates the European Space Agency's Mars Express mission. The High Resolution Stereo Camera was developed by a group with leadership at the Freie Universitat Berlin.

- NASA report @ http://www.nasa.gov/mission_pages/MRO/multimedia/gallery/mro20100624-b.html
# Via ScienceDaily (June 24, 2010) — http://www.sciencedaily.com/releases/2010/06/100624091753.htm
* Via ScienceDaily (Feb. 27, 2008) -http://www.sciencedaily.com/releases/2008/02/080226160017.htm

% Analysis by Irene Klotz from http://news.discovery.com/space/mars-was-wet-globally.html

For more material on past habitability of nearby planetary companions see http://newilluminati.blog-city.com/index.cfm?search=velikovsky

For further enlightenment see –

The Her(m)etic Hermit - http://hermetic.blog.com

New Illuminati – http://nexusilluminati.blogspot.com

http://newilluminati.blog-city.com

New Illuminati on Facebook - http://www.facebook.com/pages/New-Illuminati/320674219559

The Prince of Centraxis – http://centraxis.blogspot.com

This material is published under Creative Commons Copyright (unless an individual item is declared otherwise by copyright holder) – reproduction for non-profit use is permitted & encouraged, if you give attribution to the work & author - and please include a (preferably active) link to the original along with this notice. Feel free to make non-commercial hard (printed) or software copies or mirror sites - you never know how long something will stay glued to the web – but remember attribution! If you like what you see, please send a tiny donation or leave a comment – and thanks for reading this far…

From the New Illuminati – http://nexusilluminati.blogspot.com

http://newilluminati.blog-city.com

Thursday, 24 June 2010

NASA's great gravity mystery

An unexplained force [or field] appears to be acting against identical Pioneer probes - and at least four others

NASA

An artist's interpretation of NASA's Pioneer 10 probe looking back at the sun as it leaves the solar system.

It’s been years since NASA last heard from either of its two Pioneer probes hurtling out of the solar system, but scientists are still debating the source of an odd force pushing against the outbound spacecraft.

Dubbed the Pioneer Anomaly, the unexplained force appears to be acting against NASA’s identical Pioneer 10 and 11 probes, holding them back as they head away from the sun.

Whether that force stems from the probes themselves, something exotic like dark matter, or some new facet of physics or gravity, remains in doubt.

But a wealth of newly recovered data and telemetry, spanning decades of observations by both Pioneer 10 and 11, may yield the final answer to whether conventional physics or perhaps something new is at work on the two spacecraft…

“I would like to see this story reach its finality,” said Slava Turyshev, an astrophysicist with NASA’s Jet Propulsion Laboratory (JPL) who has spent the last 14 years—some of it on his own time—studying the Pioneer Anomaly. "So if it’s conventional physics, that’s fine and we can all go about our daily business. But if it’s something else, there may be another page.”

He and other fellow devotees discussed the astrophysics oddity… during the Seventh Annual Asimov Debate at the American Museum of Natural History.

Turyshev’s international team includes researchers from all Pioneer Anomaly camps, with some learning towards a conventional physics explanation while others trend toward the unknown fringe. Still other researchers have their own opinions.

“If I were a betting man, which I am not, I would bet a whole case of cranberry juice that the Pioneer Anomaly will have an ordinary explanation that is within known physics,” said Irwin Shapiro, an astrophysicist at Harvard University unaffiliated with the Pioneer Anomaly research team, during the debate.

Shapiro said that the number of actual instances in which oddities like the Pioneer Anomaly have opened pathways to fundamentally new physics are rare, and that ongoing studies may yet yield a conventional explanation.

Perplexing push

Launched in 1972 and 1973, Pioneer 10 and 11 are both billions of miles from Earth as they zoom out of the solar system in opposite directions.

As of Feb. 6, Pioneer 10 was about 92.12 astronomical units (AU) from the sun and headed towards the constellation Taurus. One AU is the distance between the Earth and sun, or about 93 million miles (150 million kilometers).

Researchers first noticed the Pioneer Anomaly as a navigation discrepancy while bouncing microwaves off each Pioneer probe as they moved farther from Earth. They found an unexpected drift in each probe’s Doppler frequency, one so small that the three-axis stabilized probes like NASA’s Voyager spacecraft—also headed out of the solar system—may have drowned it out with their in-flight activities.

The Doppler effect is the shortening or lengthening of waves, such as the pitch change of an ambulance as it approaches, races past, then heads away from you “We had a fitting model and it had all the effects in it that would influence the spacecraft out in interstellar space, except that it didn’t work,” said John Anderson, a retired JPL researcher who first discovered the Pioneer Anomaly. “And all we had to do to make it work was to add a constant acceleration towards the sun.”

The discrepancy found that Pioneer 10 and 11 were each about 240,000 miles (400,000 kilometers) closer to the sun than they should be according to the current understanding of gravity. Isaac Newton described gravity as a force that weakens with distance, and the Pioneer probes are speeding out of the solar system at about 30,000 miles (48,280 kilometers) per hour...

From http://www.msnbc.msn.com/id/17815839/

Five spacecraft experience unexpected anomalies in their motions

U.S. researchers are now collaborating with German colleagues to search for possible anomalies in the Rosetta probe’s second flyby of the Earth on November 13.

Mysteriously, four spacecraft that flew past Earth have each displayed unexpected anomalies in their motions.

These newfound enigmas join the so-called "Pioneer anomaly" as hints that unexplained forces may appear to act on spacecraft.

A decade ago, after rigorous analyses, anomalies were seen with the identical Pioneer 10 and 11 spacecraft as they hurtled out of the solar system. Both seemed to experience a tiny but unexplained constant acceleration toward the sun.

A host of explanations have been bandied about for the Pioneer anomaly. At times these are rooted in conventional science — perhaps leaks from the spacecraft have affected their trajectories. At times these are rooted in more speculative physics — maybe the law of gravity itself needs to be modified.

Now Jet Propulsion Laboratory astronomer John Anderson and his colleagues — who originally helped uncover the Pioneer anomaly — have discovered that five spacecraft each raced either a tiny bit faster or slower than expected when they flew past Earth en route to other parts of the solar system.

‘Humble and perplexed’

The researchers looked at five deep-space probes — Galileo to Jupiter, the NEAR mission to the asteroid Eros, the Rosetta probe to a comet, Cassini to Saturn and the Messenger craft to Mercury. Each spacecraft flew past our planet to either gain or lose orbital energy in their quests to reach their eventual targets. (Galileo made two flybys.)

The scientists confirmed anomalies in five of the six flybys, involving four of the five spacecraft.

"I am feeling both humble and perplexed by this," said Anderson, who is now working on the anomaly as a retiree. "There is something very strange going on with spacecraft motions. We have no convincing explanation for either the Pioneer anomaly or the flyby anomaly."

In the one case where researchers did not confirm a noticeable anomaly, Messenger's flyby, the spacecraft approached Earth at about latitude 31 degrees north and receded from Earth at about latitude 32 degrees south. "This near-perfect symmetry about the equator seemed to result in a very small velocity change, in contrast to the five other flybys," Anderson explained. The change in velocity was so small no anomaly could be confirmed.

The five other flybys involved flights whose incoming and outgoing trajectories were asymmetrical with each other in terms of their orientation with Earth's equator.

For instance, the NEAR mission approached Earth at about latitude 20 south and receded from the planet at about latitude 72 south. The spacecraft then seemed to fly 13 millimeters (a half-inch) per second faster than expected. While this is just one-millionth of that probe's total velocity, the precision of the velocity measurements was 0.1 millimeters per second, carried out as they were using radio waves bounced off the craft. This suggests the anomaly seen is real — and in need of an explanation.

The fact this effect seems most evident with flybys most asymmetrical with respect to Earth's equator "suggests that the anomaly is related to Earth's rotation," Anderson said.

As to whether these new anomalies are linked with the Pioneer anomaly, "I would be very surprised if we have discovered two independent spacecraft anomalies," Anderson told Space.com. "I suspect they are connected, but I really do not know."

Unbound idea

These anomalies might be effects we see with an object possessing a spacecraft's mass, between 660 and 2,200 pounds (300 to 1,000 kilograms), Anderson speculated.

"Another thing in common between the Pioneer and these flybys is what you would call an unbound orbit around a central body," Anderson said. "For instance, the Pioneers are flying out of the solar system — they're not bound to their central body, the Sun. For the other flybys, the Earth is the central body. These kinds of orbits just don't occur very often in nature — it could be when you get into an unbound orbit around a central body, something goes on that's not in our standard models."

The researchers are now collaborating with German colleagues to search for possible anomalies in the Rosetta probe's second flyby of Earth on Nov. 13.

"We should continue to monitor spacecraft during Earth flybys. We should look carefully at newly recovered Pioneer data for more evidence of the Pioneer anomaly," Anderson added. "We should think about launching a dedicated mission on an escape trajectory from the solar system, just to look for anomalies in its motion."

Montana State University physicist Ronald Hellings, who did not participate in this study, said, "There's definitely something going on. Whether that's because of new physics or some problem with the model we have is yet to be worked out, as far as I know. A lot of people are trying to look into this."

Anderson and his colleagues will detail their latest findings in an upcoming issue of the journal Physical Review Letters.

Images - http://www.space.com/scienceastronomy/080229-spacecraft-anomaly.html

For further enlightenment see –

The Her(m)etic Hermit - http://hermetic.blog.com

New Illuminati – http://nexusilluminati.blogspot.com

http://newilluminati.blog-city.com

New Illuminati on Facebook - http://www.facebook.com/pages/New-Illuminati/320674219559

The Prince of Centraxis – http://centraxis.blogspot.com

From the New Illuminati – http://nexusilluminati.blogspot.com

http://newilluminati.blog-city.com