Last Shuttle Mission Waiting for Launch

July 8, 2011

The last NASA Space shuttle mission is on the launch pad with the countdown continuing at T minus 3 hours. Whether or not it flies today depends on the appraisal of the weather which is currently very overcast on the Florida coast. If you want to watch it you can go via the web to NASA TV

The mission is to fly to the International Space Station to deliver supplies and spare parts for the next year. After that they hope to find some new way to keep the ISS going. The Shuttle has just a four person crew, the smallest since some of the earliest flights. This is because there is no backup shuttle to rescue the astronauts if Atlantis is damaged and unsafe to return. Instead the crew would have to wait on the space station to be returned up to a year later on Russian craft.

Update: 


Lunar Eclipse in Progress

June 15, 2011

This is how the Moon looks near maximum eclipse as seen on Google/Slooh. Still a little time left to view it. Hope some of you have clear night skies unlike us!

In case you haven’t noticed you can see the eclipse live on the main google search page.

The intense red colour of the moon is due to light being refracted through the Earth’s atmosphere which scatters the blue light leaving just the red end of the spectrum to bathe the moon in a warm glow. The colour is said to have been deepened by dust from recent volcanoes.

In 2009 Japan’s Kaguya lunar orbiter took some spectacular pictures of a similar eclipse from lunar orbit. The Earth passes in front of the Sun making it look like a solar eclipse except that the Earth is bigger than the Moon so the Sun disappears for much longer. The atmosphere of the Earth continues to be illuminated by the Sun from behind like a continuous ring of twilight. In this sequence the eclipse was rising above the moon’s surface which blocked the beginning of the eclipse as aseen from the orbiter. In the final frame the Sun emerges again from behind the Earth.


Shaw Prizes for Enrico Costa, Gerald Fishman, Jules Hoffmann, Ruslan Medzhitov, Bruce Beutler, Demetrios Christodoulou and Richard Hamilton

June 7, 2011

Today seven scientists are up to $500,000 minus tax richer for having won this years Shaw Prizes.

Astronomy

First up are Enrico Costa and Gerald J Fishman for leading the NASA mission that resolved the origin of gamma ray bursts. It does not seem to many years ago since gamma-ray bursts were regarded as one of the great unsolved mysteries of science. They had first been detected in 1967 by the Vela satellites which had been placed in orbit by the US military to check that the USSR was not detonating nuclear weapons in contravention of the 1963 partial test ban treaty. Nuclear explosions would send gamma rays into space where the satellites would detect them. Instead they observed gamma ray bursts coming from space.

From 1973 when their existence was declassified until 1997, these events were so mysterious that astronomers could not even tell if they came from nearby in our galaxy or billions of years away across the universe. NASA launched the BeppoSAX satellite to try to resolve the question, In 1997 it observed a powerful gamma ray burst which left an afterglow long enough for Earth based telescopes to lock onto its location just 8 hours later. Now they could see that it came from a very distant galaxy.

The gamma rays are so bright at that distance that it is inconceivable that they are being radiated equally in all directions in such a short space of time. The amount of energy that would have to be concentrated into a small volume is juts not possible. It is thought that they come from energetic supernovae with a rapidly rotating remnant that focuses the gamma rays into a tight beam. we only see the burst for the small fraction of events where we happen to lie in the direction of the ray.

Life Science and Medicine

Next were Jules A Hoffmann, Ruslan M Medzhitov and Bruce Beutler for uncovering the biological mechanisms for innate immunity. When an animal or plant is infected it deploys a number of mechanisms to defend itself. One of the first is the innate immune system, thought to be one of the earliest mechanisms to evolve because it is so widespread across diverse forms of life. In plants it remains the dominant immune system, but advanced animals have developed more effective systems of adaptive immunity that can change to attack specific viruses or other contagents.

Understanding all forms of immunity is vital to medicine because it provides the knowledge needed to find drugs that help us fight diseases.

Mathematics

Finally, Demetrios Christodoulou and Richard S Hamilton won the mathematics prize for work on differential manifolds with implications for general relativity and the Poincaré conjecture.

When Grigori Perelman famously turned down the Fields medal and the million dollar Clay prize for resolving the Poincaré conjecture, he said that his reason was that other mathematicians such as Richard Hamilton has contributed just as much to the proof. He need not have been so concerned since Hamilton has now himself been recognized with a lucrative award.

It was Hamilton who discovered the theory of Ricci flow on differential manifolds that lead Perelman to his proof of the Thurston geometrization conjecture that was known to imply the truth of the Poincaré conjecture, a mathematical problem that had remained unsolved for a hundred years.

Demetrios Christodoulou is a mathematical physicist who worked for his doctorate at Princeton under the direction of John Wheeler. He is known for his extraordinarily difficult proof of the unsurprising fact that flat empty Minkowski space is stable under the action of nonlinear gravitational dynamics as described by general relativity.


Shuttle Endeavour ready to Launch

May 16, 2011

Endeavour is preparing to launch for its last mission of 16 days in which it will deliver CERNs Alpha Magnetic Spectrometer to the International Space Station. This experiment will measure cosmic ray fluxes and should be able to tell us if there is any antimatter at all in space. Within the Earth’s atmosphere we can detect only the byproducts of most cosmic ray collisions with the atmosphere or Earth itself. Only weakly interacting particles such as neutrinos can be detected directly. In space it is possible to measure directly the energy of cosmic ray particles before they collide, but you have to wait a long time to get a good sample.

The launch can be watched on NASA TV and is due soon

Update: the shuttle has launched on time.


How Earthlike are Kepler’s Latest Exoplanets?

February 3, 2011

I am sure everyone is aware of the latest release of exoplanet data from Kepler that has multiplied the number of known exoplanet candidates by a factor of about five. Kepler detects its exoplanets by looking for stellar transits so it is only going to see them in the rare cases where we are in alignment with the plane of the stars planetary system. Luckily it can look at a lot of stars in a patch of the sky all at the same time. In its first few months it has found well over a thousand by this method. Some of these may prove to be glitches and must be verified either by land-based observations of by repeat transits observed from Kepler.

So which is the most Earthlike  planets they have seen? To answer this you need to peruse the full set of data which can be found here. Even then the answer depends on what you consider to be the most important parameters to define an Earthlike planet. After due consideration I am going to go for Keplar-268 which has an estimated radius of 1.75 times the Earth, a year of 110 days and it sits at 0.41 astronomical units from its parent star. This should give it an estimated surface temperature of 295 degree Kelvin or 22 degrees Celcius. Admittedly it is a bit large so its gravity is going to be stronger than  we would probably enjoy.

The estimated temperature that NASA uses is based on the amount of received radiation. I’m not sure if there is any correction for greenhouse effects which depend on the density and content of its unknown atmosphere. In any case it is at least reasonable to assume that its rotation will not be locked to its star so it has a chance of being habitable with liquid water present. On the other had it’s high gravity may mean it retains too much atmosphere and suffers from permanent clouds making its surface very hot and high pressured.

This is just the first big release of data from Kepler and more can be expected, especially since many Earthlike planets will not have done a full revolution of their star in the time it has been l0oking. The results so far suggest that when all data is collected there should be some candidates for really Earthlike planets, at least in terms of size and ambient temperature. Once their location is known it will be the job of other telescopes to look at them in more detail. This will include the best Earth-based telescopes using adaptive optics and interferometry to focus in on the systems. A little later the James Webb Space Telescope should take over, if and when it successfully reaches its position to start observing in space.


First Earth-Like Planet Discovered!

January 15, 2011

So How often do we think we are going to see the headline announcing the discovery of the “First Earth-Like Planet” ? The latest example (CoRoT-7 b) came just as the New Year arrived. It turned out to be a firey world with temperatures ranging between -210 to 2000 degrees centigrade because it is tidally locked with its star. That’s not what most of us would consider Earth-Like. It earned its dubious title by being a rocky planet not very different in size than Earth.

Even as the news broke the sense of deja-vu was overwhelmingly strong. The previous “First Earth-like planet” (Gliese 581g) had been discovered just four months previously. This one is in the Goldilocks zone of its star meaning that it is at the right distance for liquid water to form on the planet. However, water would only actually form if it was rotating to give the surface an even temperature, but this one is probably tidal locked too.

Looking back through the news archives it is no surprise to find that news of the first Earth-like planets first appeared as far back as 1998 when just a handful of exoplanets were known. since then there have been a number of candidates, hopefully with each one being a little bit more Earth-like than its predecessor, although it is also the case that some of these discoveries later turn out to be errors.

At viXra log we confidently predict that the next collection of such headlines will hit us when the next major update from the Keplar mission is released on February the first, if not before. The pre-release of info about CoRoT-7 b may however signal that nothing much better has been found. In any case we can be sure that planets described as more and more Earth-like will be appearing for many years to come.

So what do we really think should be counted as an Earth-like planet? The data we get from Keplar and other observations should tell us about the planet’s size, mass, and distance from its star. From this information we can infer its average temperature, whether it is likely to be tidally locked, the strength of its surface gravity. Then from this we can make a guess about whether it could support liquid oceans of water, and an atmosphere of the right density as well as whether it has a molten iron-rich core. the latter is important because it could give the planet a magnetic field that protects it from radiation.

If “Earth-like” means a planet could support an ecosystem like ours it will need to be in the Goldilocks zone of a star that is not too dim so that it does not tidally lock and liquid water can exist. It will also need to have a size and density reasonably close to Earth’s. That will ensure that it can retain its atmosphere without it becoming too dense. It also means that large land based animals will not be hindered by excess gravity and the molten core will not solidify to remove the magnetic field as it did on Mars.

It follows form these considerations that the star around which the planet orbits must also be like our Sol. If it were less bright the planet would need to get nearer and would be tidally locked. Bigger stars tend not to last long enough to provide a stable environment in which life can evolve. Other types of star may be too variable in brightness, or may have regular deadly flares that could strip any nearby planet of its atmosphere, even with the protection of a magnetic field.

Taking these things into consideration, the parameters that we can currently measure of exoplanets and the stars they orbit need to be very close to those of Earth and our Sun.

Apart from these considerations, an important feature of our planet is its large moon. Without it there would be no tides and these have surely been very important in promoting the evolution of live. The Moon is also said to keep our planet’s rotation axis stable. If it were otherwise we might suffer catastrophic changes in climate that would ruin the atmosphere of our planet. There may be an outside chance that Kepler could see the presence of such a moon as the system transits in front of its star.

Even if a star meets these requirements it really just makes it potentially Earth-like. The planet also needs to have the right chemical mix of elements in the right quantities to make oceans and an atmosphere that would support rather than poison life. Will we ever be able to detect their presence?

After Keplar has made a long (hopefully) list of potentially Earth-like exoplanets the next step will be to examine them more closely using other observatories. The best hope of being able to do this in the foreseeable future lies with the James Webb Space Telescope that is due for launch in 2014. The JWST will have spectrometers sensitive enough to see the slight differences in a systems spectra when planets pass behind their stars. It will even have a special camera with a spot that can block out the light from a star so that some planets can be seen away from the glare. This should certainly be good enough to work for the gas giants but it may require the next generation of space telescope to be able to do the same for smaller (potentially) Earth-like planets.

In the long term the prospects for finding truly Earth-like planets can only get better. Just how fast depends on technological and economic developments that are hard to predict. Ultimately there is no reason why we should not be able to determine the chemical composition of the atmospheres of Earth-sized exoplanets and if they have the right proportions of oxygen and nitrogen we will know that Earth-like plant and animal life must be present. Perhaps we will even be able to see the tale-tale signature of chlorophyl or other molecules that can only be produced in quantity by vegetation. That’s  if such planets even exist nearby.

In any case one thing is for sure:  Headlines telling us of the “First Earth-like Planets” are going to be around for some time.


The NASA Astrobiology News Conference

December 1, 2010

Tomorrow (2nd December) at 2pm EST NASA will hold a press conference “to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life” This sounds fairly exciting and of course it’s an invitation to science bloggers to speculate about  what they might have discovered. At a previous press conference in 1996 NASA announced that it had found bacteria-like structures in a meteorite that had come to Earth from Mars. Could tomorrow’s announcement be something similar?

The only clue we get is a list of scientists who will attend the press conference and who are probably the authors of a paper to be published in Science on the discovery, whatever it is. Here is a brief summary of their profiles

  • Mary Voytek: A microbiologist interested in aquatic microbial ecology and biogeochemistry. She has studies life in extreme conditions on Earth suxh as deep-sea hydrothermal vents and terrestrial deep-subsurface sites and is an Interim Senior Scientist for Astrobiology in the Science Mission Directorate at NASA HQ.
  • Felisa Wolfe-Simon:a NASA Astrobiology Research Fellow through the NAI and Exobiology at NASA. She has studied (hypothetical) life forms with unusual chemistry including arsenic-based life.
  • Pamela Conrad: Works at NASA’s Virtual Planetary Laboratory and studies signatures for life and planetary habitability assessment.
  • Steven Benner: A biochemist who runs a laboratory that aims to create artificial life. The lab also studies bio-signatures from planets other than Earth and is working with NASA to deign the next generation of probes to Mars
  • James Elser: A researcher in the field of biological stoichiometry, the study of balance of energy and multiple chemical elements in living systems. Currently, he is an active member of the ASU’s NASA-funded Astrobiology project “Follow the Elements”

So what do we think this is about? The intriguing possibility is that the team has indeed found some biological signature indicating the possibility of extraterrestrial life. It could be something as simple as oxygen or an amino acid. This could be an observation from a probe looking at a planet or moon in the solar system such as Mars, Titan, Europa or Rhea. Alternatively it could be from another metiorite found on Earth, or a comet. A discovery related to exoplanet searches is also possible but does not seem to be such a good fit.

Of course it is also possible that the discovery is something less extraterrestrial, such as an unusual life-form found on Earth. It is not likely to be the discovery of a radio signal from extraterrestrials because the expert profiles are wrong, but who knows?

Update (2-Dec-2010): The announcement turns out to be that the scientists have taken a microbe from the arsenic rich waters of lake Como and put it in a soup which is rich in arsenic and low in phosphorus.

Arsenic is highly poisonous to us because it is chemically similar to phosphorus and replaces phosphorus in the molecules in our body, but it is not close enough for this to work. However, what was found was that there is one bacteria from the lake that takes in the arsenic and continues to live and subdivide. In particular the phosphorus in the DNA of the bacteria gets replaced with arsenic.

This is interesting because it means that DNA based extraterrestrial life might evolve in environments that don’t have phosphorus.

Some websites are still reporting that they have discovered a completely new type of lifeform that uses arsenic instead of phosphorus. This is not quite the situation. Instead it is a conventional microbe with a remarkable ability to use arsenic instead of phosphorus when necessary.

Update (3-Dec-2010): There was an interesting moment in the press conference when Benner tried to explain why he is so sceptical about this discovery. He said that phosphor gets incorporated into life’s molecules through a complex sequence of 14 enzyme catalysed reactions. Although arsenic is chemically similar to Phosphorus, it is not so similar that it could substitute into such a reaction sequence, therefore it is hard to see how it could get into DNA.

Wolfe-Simon came back with a simple response. While phosphor based chemicals are hard to produce, their arsenic based counterparts form spontaneously in a testtube when you mix the chemicals together!

Of course this does not completely answer the objection, it is still hard to see how an alternative chemical pathway can exist inside these bacteria, but if Wolfe-Simon has done her work well, that is exactly what is happening.

If we speculate a little beyond what was said the implication for the formation of life both on Earth and extraterrestrial is startling. It is one of the great puzzles of science that basic life arose spontaneously from the primordial soup on Earth. If the chemical reactions that life uses are so complex how could they have arisen naturally?

Suppose the Lake Como bacteria is not just a remarkable micro-organism that has adapted to an arsenic based environment. Could it be a throw-back to an earlier form of life that evolved from scratch in a chemical soup where the molecules for life could form spontaneously using arsenic instead of phosphor?

Arsenic based molecules are less stable than their phosphorus equivalents, so if an arsenic based micro-organism could adapt to using phosphorus it would be able to make the leap to water dominated environments where evolution can progress. So the Como Lake bacteria may not be phosphorus based life that adapted to arsenic at all. It could be arsenic based life that adapted to use phosphorus, but unlike other more evolved cells, it retains the mechanisms needed to live off arsenic.