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Earth is a pale blue dot when viewed from space. Now astrobiologists have worked out the likely colours of Earth-like planets orbiting other stars

Astronomers hunting for another Earth have found what may be the closest match yet, a potentially rocky planet circling its star at the same distance as the Earth orbits the Sun, NASA said Thursday.

so it took us 70% of the time Earth is in the habitable zone to develop, would this be normal or could it be much faster? In other words, would all forms of life that started on a planet that originated at a 'similar' point in time like us, be equally far developed?

That is actually quite tricky to estimate rly. If for no other reason than the fact that all of the mass extinctions we had over the Earth's history basically reset the evolutionary clock. Assuming 2 Earths identical in every way but one did not have the dinosaur wipe-out impact, that would've given non-impact Earth 60million years to evolve a potential dinosaur intelligent super race.

The opposite might be true - or might not be ;-). Since usually the rate of evolution increases after major extinction events the chance is higher to produce 'intelligent' organisms if these events happen quite frequently. Usually the time of rapid evolution is only a few million years - so Earth is going quite slow. Certainly extinction events don't reset the evolutionary clock - if they would never have happened Earth gene pool would probably be quite primitive. By the way: dinosaurs were a quite diverse group and large dinosaurs might well have had cognitive abilities that come close to whales or primates - the difference to us might be that we have hands to manipulate our environment and vocal cords to communicate in very diverse ways. Modern dinosaur (descendents), i.e. birds, contain some very intelligent species - especially with respect to their body size and weight.

Let's all start up some crazy space companies together: harvest hydrogen on Jupiter, trap black holes as unlimited energy supplies, use high temperatures close to the sun to bake bread! Apparently it is really easy to do just about anything and Deep Space Industries is really good at it. Plus: in their video they show Mars One concepts while referring to ESA and NASA.

hmm aside from the technological feasibility, their approach still should be taken as an example, and deserve a little support. By tackling such difficult problems, they will devise innovative stuffs. Plus, even if this doom-to-fail endeavour may still seem you useless, it creates jobs and make people think... it is already a positive! Final word: how is that different from what Planetary Resources plan to do? It is founded by a bunch of so-called "nuts" ... (http://www.planetaryresources.com/team/) ! a little thought: "We must never be afraid to go too far, for success lies just beyond" - Proust

I don't think that this proposal is very different from the one by Planetary Resources. My scepticism is rooted in the fact that - at least to my knowledge - fully autonomous mining technology has not even been demonstrated on Earth. I am sure that their proposition is in principle (technically) feasible but at the same time I do not believe that a privately funded company will find enough people to finance a multi-billion dollar R&D project that may or may not lead to an economically sensible outcome, i.e. generate profit (not income - you have to pay back the R&D cost first) within the next 25 years. And on that timescale anything can happen - for all we know we will all be slaves to the singularity by the time they start mining. I do think that people who tackle difficult problems deserve support - and lots of it. It seems however that up till now they have only tackled making a promotional video... About job creation (sorry for the sarcasm): if usefulness is not so important my proposal would be to give shovels to two people - person A digs a hole and person B fills up the same hole at the same time. The good thing about this is that you can increase the number of jobs created simply by handing out more shovels.

Sometime in the last few billion years, disaster struck one of Earth's nearest neighbours. Planetary geologists think there is good evidence that Venus was the victim of a runaway greenhouse effect which turned the planet into the boiling hell we see today. A similar catastrophe is almost certain to strike Earth in about 2 billion years, as the Sun increases in luminosity.

the actual paper: http://arxiv.org/abs/1201.1593 just wondering if their conclusion that the long term solution is to change the orbit of Earth is really the ultimate wisdom ...

Another underestimated source of CO2, are turbulent waters. "The stronger the turbulences at the water's surface, the more CO2 is released into the atmosphere. The combination of maps and data revealed that, while the CO2 emissions from lakes and reservoirs are lower than assumed, those from rivers and streams are three times as high as previously believed." Alltogether the emitted CO2 equates to roughly one-fifth of the emissions caused by humans. Yet more stuff to model...

Nasia, I thought about your statement carefully - and I cannot agree with you. Water is not a greenhouse gas. It is instead a liquid. Also, I can't believe you keep feeding the troll! :-P But on a more topical note: I think it is an over-simplification to call water a greenhouse gas - water is one of the most important mechanisms in the way Earth handles heat input from the sun. The latent heat that you mention actually cools Earth: solar energy that would otherwise heat Earth's surface is ABSORBED as latent heat by water which consequently evaporates - the same water condenses into rain drops at high altitudes and releases this stored heat. In effect the water cycle is a mechanism of heat transport from low altitude to high altitude where the chance of infrared radiation escaping into space is much higher due to the much thinner layer of atmosphere above (including the smaller abundance of greenhouse gasses). Also, as I know you are well aware, the cloud cover that results from water condensation in the troposphere dramatically increases albedo which has a cooling effect on climate. Furthermore the heat capacity of wet air ("humid heat") is much larger than that of dry air - so any advective heat transfer due to air currents is more efficient in wet air - transporting heat from warm areas to a natural heat sink e.g. polar regions. Of course there are also climate heating effects of water like the absorption of IR radiation. But I stand by my statement (as defended in the above) that rain cools the atmosphere. Oh and also some nice reading material on the complexities related to climate feedback due to sea surface temperature: http://journals.ametsoc.org/doi/abs/10.1175/1520-0442(1993)006%3C2049%3ALSEOTR%3E2.0.CO%3B2

I enjoy trolling conversations when there is a gain for both sides at the end :-) . I had to check upon some of the facts in order to explain my self properly. The IPCC report states the greenhouse gases here, and water vapour is included: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-2-1.html Honestly, I read only the abstract of the article you posted, which is a very interesting hypothesis on the mechanism of regulating sea surface temperature, but it is very localized to the tropics (vivid convection, storms) a region of which I have very little expertise, and is difficult to study because it has non-hydrostatic dynamics. The only thing I can comment there is that the authors define constant relative humidity for the bottom layer, supplied by the oceanic surface, which limits the implementation of the concept on other earth regions. Also, we may confuse during the conversation the greenhouse gas with the Radiative Forcing of each greenhouse gas: I see your point of the latent heat trapped in the water vapour, and I agree, but the effect of the water is that it traps even as latent heat an amount of LR that would otherwise escape back to space. That is the greenhouse gas identity and an image to see the absorption bands in the atmosphere and how important the water is, without vain authority-based arguments that miss the explanation in the end: http://www.google.nl/imgres?imgurl=http://www.solarchords.com/uploaded/82/87-33833-450015_44absorbspec.gif&imgrefurl=http://www.solarchords.com/agw-science/4/greenhouse--1-radiation/33784/&h=468&w=458&sz=28&tbnid=x2NtfKh5OPM7lM:&tbnh=98&tbnw=96&zoom=1&usg=__KldteWbV19nVPbbsC4jsOgzCK6E=&docid=cMRZ9f22jbtYPM&sa=X&ei=SwynUq2TMqiS0QXVq4C4Aw&ved=0CDkQ9QEwAw

website of the project working on the 'Living Earth Simulator': http://www.futurict.ethz.ch/FuturICT five page summary of the FuturICT Proposal: http://www.futurict.ethz.ch/data/FuturICT-FivePageSummary.pdf

Did you know about this Weather Modification Office? Promising or dodgy?

Yes. In China it happens apparently quite often that weather is regionally modified, e.g. in order to have good weather conditions during certain events (like olympics in Beijing). But also in other countries weather modification is applied, for reasons of agriculture, pollution, skiing, etc. Obviously, one wonders on the environmental impact of such an artificial cloud feeding process with silver iodide. I just googled, stumbling upon this report http://www.weathermodification.org/AGI_toxicity.pdf which published the result: no environmentally harmful effects...

and w.r.t. ur question: I mean different weather conditions which we experience locally (like droughts or other extreme weather events) are (often) due to large-scale/global climatic changes. Hence, cloud seeding just describes a local, short-term mitigation of these events. However, there is a geoengineering proposal (so climate modification) which also suggests to seed clouds above the sea (i.e. increase cloud coverage, e.g. by using seaspray as cloud condesation nuclei), thereby increasing the planetary albedo (Earth reflectance) and reducing the energy reaching the Earth surface. If this idea is promising or not, I couldn't judge upon, but for sure it is worthwhile to take a closer look at.

An international team of researchers have developed a new type of gyroscope that is the first to measure the "wobble" in the rotational axis of the Earth from a ground-based laboratory. Astronomers normally track this wobble by continuously monitoring the position of distant objects, such as quasars. But this new method will provide a much simpler and cheaper alternative to these large-scale astronomical readings, the scientists claim.

is this of any use for spacecraft?

mmm it's like saying that you can replace satellite tracking by accelerometers on-board satellites... for Leo: you'd better put an atomic gyro on a spacecraft these laser gyro are huge !

nice movie

At the link below you find additional information about the projects: Education: Ten weeks to save the world http://www.nature.com/news/2010/100915/full/467266a.html

well, most good ideas probably take only a second to be formulated, it's the details that take years :-)

I do not think the point of the SU is to formulate new ideas (infact there is nothing new in the projects chosen). Their mission is to build and maintain a network of contacts among who they believe will be the 'future leaders' of space ... very similar to our beloved ISU.

Let's start betting which party Aliens vote: GREEN, BLUE, RED, BLACK?

http://astrobiology.nasa.gov/ for the moment is down. My bet, the microbe they found notified its cousins and they are currently invading the US

you can still see the rest of it here: http://www.nasa.gov/multimedia/nasatv/index.html a good link with a summary and discussion on the announcement is here: http://www.guardian.co.uk/science/2010/dec/02/nasa-life-form-bacteria-arsenic

also interesting (for the Earth Science girls): Nilton Renno of the University of Michigan, who studies how rocket plumes from Mars landers affect the Martian surface.

Anyone out there still doing propulsion stuff? Two more papers just waiting to get busted... http://arxiv.org/abs/0908.1429v1 http://arxiv.org/abs/0908.1803

One reply to Pacome, though the discussion exceeds by far the relevance of the topic already. Baryonic DM is strictly limited by cosomology, if one believes in these models, of course. Anyway, even though most DM is cold, we are constantly bombarded by some DM particles that come together with cosmic radiation, solar wind etc. etc. If DM easily interacted with normal matter, we would have found it long ago. In the paper they consider DM as neutralinos, which are neither baryonic nor strongly or electromagnetically interacting.

well then I agree, how the fu.. they want to collect them !!!

This look like a perfect ACT project :)

That is about € 14e9 - enough to pay more than a million YGTs for half a year. Could we use maybe just half a million YGTs for half a year to build a similar platform and keep the remaining € 7e9 for ourselves? Keep in mind that WhatsApp only has 45 employees (according to AllThingsD: http://goo.gl/NtJcSj ). So we would have an advantage > 10000:1. On the other hand does this mean that every employee at WhatsApp gets enough money now to survive comfortably for ~5000 years or will the inevitable social inequality strike and most people get next to nothing while a few get money to live comfortably for ~1000000 years? Also: Does Facebook think about these numbers before they pay them? Or is it just a case of "That looks tasty - lets have it"? Also (2): As far as I can see all these internet companies (Google, Facebook, Yahoo, WhatsApp, Twitter...) seem to make most of their income from advertising. For all these companies together that must be a lot of advertising money (turns out that in 2013 the world spent about $ 500 billion on advertising: http://goo.gl/vYog15 ). For that money you could of course have 20 million YGTs roaming the Earth and advertising stuff door-to-door... ... ...

The whole valuation of those internet companies is a bit scary. Things like the Facebook and Twitter ipo numbers seem just ridiculous.

Facebook is not really so much buying into a potential good business deal as much as it's buying out risky competition. Popular trends need to be killed fast before they take off the ground too much. Also the amount of personal data that WhatsApp is amassing is staggering. I have never seen an app requesting so many phone rights in my life.

Interesting read if you're interested on the kind of coding that goes into something like the Curiosity rover. :) btw.. nice fill-packet being sent by Curiosity: "Elvis has Spirit. The answer is 42....END\r\n"

Redshift in this model is partially produced by a change in the masses of elementary particles (and atoms)

It should not be impossible to verify a change in mass(es) over time. For example the electron cyclotron frequency scales ~e/m while the Hydrogen emission frequencies scale with ~m*e^4. Using multiple relationships like that which can be easily and accurately measured an increase in the mass of fundamental particles should - in principle - be detectable (even if the mass of the earth increases at the same time changing the relativistic reference frame).

The Watt balance and a definition using the Planck's constant seems to do the trick and is currently being discussed. Would the electron charge not be problematic as it is related to Coulombs which depends on Amperes which is defined by Newtons which hence depends back on the mass again?

Seems a little speculative but pretty interesting thoughts. In regards to terraforming Mars this might be of interest: "During the daytime, plant-like microorganisms on a Martian-like surface could photosynthesize hydrogen peroxide. At night, when the atmosphere is relatively humid, they could use their stored hydrogen peroxide to scavenge water from the atmosphere, similar to how microbial communities in the Atacama use the moisture that salt brine extracts from the air to stay alive."

...and hitting the news in the same day: A Rocket Built from U.S. and European Parts "A new rocket that would combine parts from NASA's canceled Ares I rocket as well as the Ariane 5 , a well-proven European satellite launcher, could provide a low-cost option for taking crew and cargo to the space station. The rocket proposal was announced this week by ATK, an aerospace and defense company that manufactures the solid rocket motors for NASA's space shuttles, and Astrium, the European company that makes the Ariane 5. They say the rocket, called Liberty, would be ready for flight by 2015." "Other commercial companies, including Boeing and Orbital Sciences Corporation, are looking to use low-end versions of the Atlas V to carry the capsules they are building. Liberty could carry any capsule at a cost less than that of the Atlas V, according to ATK." Look! Competition! :)