Astronomy

Google Contributes Funding to NASA Space Science Technology + Mission

Matt Daniels — Tue, 10 Jun 2008 00:21:21 -0700

Description

Google has contributed funding to the Transiting Exoplanet Survey Satellite (TESS), a NASA spacecraft (smallsat) in cooperation with MIT and the Harvard Smithsonian Center that could potentially be launched in 2012.

Google, the Internet search powerhouse that in recent years has expanded to include mapping of the stars as well as the surfaces of the moon and Mars and which has an ongoing collaboration with NASA's Ames Research Center, provided a small seed grant to fund development of the wide-field digital cameras needed for the satellite. Because of the huge amount of data that will be generated by the satellite, Google has an interest in working on the development of ways of sifting through that data to find useful information.

It's interesting that private companies seem to be increasingly funding large science projects.... (N.B., I've noticed this mostly in the physical sciences...)

Engineering & Design

Source

http://web.mit.edu/newsoffice/2008/google-planets-tt0319.html

Juan Collar on Dark Matter Detection | Response to Italian DAMA Experiment

Matt Daniels — Tue, 29 Apr 2008 10:15:49 -0700

Description

Criticism of the DAMA/LIBRA collaboration's conclusions regarding dark matter detection

From Cosmic Variance: You may have heard some of the buzz about a new result concerning the direct detection of dark matter particles in an underground laboratory. The buzz originates from a new paper by the DAMA/LIBRA collaboration; David Harris links to powerpoint slides from Rita Bernabei, leader of the experiment, from her talk at a meeting in Venice.

The controversy surrounding the DAMA/LIBRA collaboration points to the fact that the search for evidence about the nature of dark matter (and WIMPs) is still wide open... particle physics has a ways left to go in unraveling this (despite claims made by the Italian/Chinese DAMA/LIBRA collaboration).

Selections from Juan Collar's guest post on Cosmic Variance regarding the claims made by DAMA/LIBRA collaboration (some editorials left intact):

* The modulation is undeniable by now. I don’t know of any colleagues who doubted these data were blatantly modulated already back in 2003, when “the lady” (DAMA) decided to keep mum for a while. However, to conclude from something this mundane that the experiment “confirms evidence of Dark Matter particles in the galactic halo with high confidence level” or that there is “an evidence for the presence of dark matter particles in the galactic halo at 8.2 sigma confidence level” is simply delusional. There is evidence for a modulation in the data at 8.2 sigma, stop. Compatible with what would be expected from some dark matter particles in some galactic halo models, full stop. Anything beyond this is wanting to believe, and it smears on the rest of us in the field.

* Someone should take the DAMA folks aside for a beer, make them see the following. If one day soon we are all convinced that this effect was DM-induced (see below for what that will really take), they will be recognized for one of the greatest discoveries in the history of science, without them having to look desperate or foolish today. Or making the rest of us in the field do, by association: thanks DAMA, for cheapening the level of our discourse to truly imbecilic levels.

* It is not DAMA’s fault that there is a penury of signatures in this field of ours, laboratory searches for particle dark matter. The one possible exception to this is a detector with good recoil directionality and sufficient target mass to be truly competitive, but we don’t know of a good enough way to do this as of today (“good enough” folds in the price tag). People are still trying. The diurnal modulation in the DM signal that would be sensed by such a device is wickedly rich in features, extremely hard for nature to imitate with anything else. The annual modulation resides on the other side of this spectrum of complexity. It is the poor man’s smoking-gun to DM “evidence”. Inspected carefully, it is disappointingly feeble: different models of the halo can shift the phase of this modulation completely, turning expected maxima into minima and vice-versa, changing the expected amplitude as well. Add to this the fact that essentially every possible systematic effect able to pass for a “signal” can be yearly-modulated, for one reason or another. That’s the ones we can presently think of, and the ones yet to be proposed. To grow convinced that we have observed dark matter in the lab we’ll require a number of entirely different techniques, using a variety of targets, all pointing at the same WIMP (mass, cross sections), with additional back-up information from accelerator experiments and from gamma-ray satellite observations (so-called indirect searches). All of those lines crossing at one point, so to speak. This I (for one) will call “evidence”. I know of no single existing or planned DM experiment, including those I participate in, that would be able to make anything close to a bulletproof claim on its own.

* I try to teach my students that a good experimentalist does not need any critics: he or she is his/her own worst enemy. If you don’t feel a sincere drive to debunk, test and revise your own conclusions, you should be doing something else for a living. This intent is seemingly absent from the DAMA collaboration. Sure, some obvious environmental parameters are kept constant and logged. But this is simply not enough. Again we see, like the last time, that the subject of a modulation in the photomultiplier (PMT) noise contaminating the data, which is on everyone’s mind, is treated in a quite unsatisfying, suspiciously ad hoc fashion.

* More rigorous versions: concentrate on blank runs with low-background non-scintillating or low-scintillation materials (synthetic quartz, acrylic, undoped NaI, etc.) in place of the sodium iodine crystals. The materials should still be as close as possible, optically speaking, to the original scintillator, to allow for PMT cross-talk effects such as dynode glow, etc. Acquire data (PMT noise, Cerenkov light in the envelope, and other known nuisances in this case) and demonstrate that the modulation is absent then, that the effect was in the NaI scintillation. Another possible test: you are sitting on almost 1000 kg-yr of data. This should provide DAMA with a sensitivity to diurnal modulations smaller than ~0.1%. It then seems statistically possible to find weak additional DM effects originating exclusively from the rotational speed of the laboratory around the Earth’s axis (see footnote in astro-ph/9808058v2), a far more complex piece of “evidence”. Such effects depend on the sidereal day (as opposed to the solar day) and are hard to mask by anything not of a galactic origin. Try, doggammit, try to put your experiment to the acid test instead of serving yesteryear’s cold leftovers again! DAMA can now proceed to do with this free advice the same as with the rest received from others. Too crude to print in this distinguished forum.

* Kudos to DAMA on more than a couple of fronts: they have really made it very hard for other experiments using the same target (ANAIS, NAIAD, etc.) to match their sensitivity. It seems urgent by now to repeat the experiment independently, using the same detection medium. DAMA has done an extraordinary job in removing radioactive contaminants from NaI, better than anyone else to date. I do go out and defend DAMA (believe it or not) when folks too far afield attempt to criticize the quality of the experiment itself. They have done a phenomenal job (the experiment is a class act, their reasoning and public relations…). Another area where they excel is in reminding us that the dark matter possibilities are actually many, and that not all doors are closed on a real effect. Not nearly. Through the years they have proposed and compiled dark matter alternatives capable of explaining their effect but not yet tested by other experiments. Nothing wrong with this, as long as you don’t confuse it with “evidence” for anything. This should encourage creative approaches in a field that is not particularly notorious for them: we are all looking for the same type of particle, focusing on a particular region of WIMP phase space, relying on the same mode of interaction. If anything, the history of particle physics teaches us that surprises abound: often, whenever a natural hypothesis prevailed (relatively heavy SUSY WIMPs or light axions in our case) incoming experimental data forced the community to regroup, rethink and come up with other explanations. These always look evident with the privilege of hindsight. We are a certifiable ship-o-fools, let us not forget.

Physics & Space Science

Source

Cosmic Variance post: http://cosmicvariance.com/2008/04/21/guest-post-juan-collar-on-dark-matter-detection/

More on dark matter: http://cosmicvariance.com/2008/02/27/whats-the-dark-matter/

DAMA: http://en.wikipedia.org/wiki/DAMA/NaI
DAMA Paper: http://arxiv.org/abs/0804.2741

NYT: Physicists Renew Claim, in New Experiment, of Detecting Dark Matter Particles

Next Generation of Astronomical Observatories in Chile

Matt Daniels — Thu, 03 Apr 2008 12:12:46 -0700

Description

Several of the world's most prominent next generation observatories are being planned for construction in Chile's high desert regions. The dark skies, high fraction of clear nights, and ability to acquire high-quality images make Chile an ideal location for large telescopes.

Planned observatories include:

Atacama Large Millimeter/Submillimeter Array: ALMA

The Atacama Large Millimeter Array (ALMA) is an international astronomy facility. ALMA is an equal partnership between Europe and North America, in cooperation with the Republic of Chile, and is funded in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC), and in Europe by the European Southern Observatory (ESO) and Spain. ALMA construction and operations are led on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI), and on behalf of Europe by ESO.

ALMA Science:
The Atacama Large Millimeter Array (ALMA) will be the forefront instrument for studying the cool universe - the relic radiation of the Big Bang, and the molecular gas and dust that constitute the very building blocks of stars, planetary systems, galaxies, and life itself. This material typically resides at temperatures of 3-100 K, resulting in spectral energy distributions peaking at submillimeter through to far-infrared wavelengths. Most of the energy in the Universe lies in two thermal components - the cosmic background and the far infrared background - whose Earth-accessible spectrum lies within the ALMA frequency coverage. Indeed, the peak of the spectral energy distribution for dusty objects in the distant universe becomes redshifted entirely to submillimeter wavelengths. While a number of current and future telescopes will operate at submillimeter wavelengths in order to exploit the wealth of information available in this part of the electromagnetic spectrum, none will have the combination of sensitivity, resolution, and frequency coverage of ALMA.

From: http://www.alma.nrao.edu/

Giant Magellan Telescope: GMT

The Giant Magellan Telescope (GMT)—the product of more than a century of astronomical research and telescope-building by some of the world’s leading research institutions—will open a new window on the universe for the 21st century. Scheduled for completion around 2017, the GMT will have the resolving power of a 24.5-meter (80 foot) primary mirror—far larger than any other telescope ever built. It will answer many of the questions at the forefront of astrophysics today and will pose new and unanticipated riddles for future generations of astronomers. ...The GMT project is currently focused on sites in central and northern Chile.

GMT Science:
The GMT will produce images up to 10 times sharper than the Hubble Space Telescope.
Presently we are able to detect planets only by indirect means. The GMT will allow us to make images of planets around nearby stars and, possibly, discern their chemical compositions. Designed with high contrast imaging in mind, the GMT will have the ability to detect faint terrestrial-like planets in the presence of enormous glares from their parent stars. ...[Likewise,] the GMT, operating with adaptive optics to achieve its maximum resolving power, can probe the centers of distant galaxies in unprecedented detail.

Current ground-based telescopes cannot probe supernovae to sufficient distances to provide a definitive test of competing models of the Dark Energy. The GMT will allow us to observe Supernovae to the highest redshifts and will aid in the full characterization of the expansion history of the Universe.

From: http://www.gmto.org/

Physics & Space Science

Source

Atacama Large Millimeter/Submillimeter Array:
http://www.alma.nrao.edu/

Giant Magellan Telescope:
http://www.gmto.org/

Methane Discovered in Exoplanet Atmosphere

Matt Daniels — Thu, 20 Mar 2008 15:11:31 -0700

Description

Researchers report in tomorrow's issue of Nature that a 40-minute gaze with the Hubble Space Telescope last May [2007] has revealed methane in the atmosphere of HD 189733b, a Jupiter-size planet orbiting close to its very bright parent star located 63 light-years away. The observation also confirmed last year's discovery by the Spitzer Space Telescope of water vapor in the planet's atmosphere (see: ScienceNOW, 11 July 2007).

ESA calls this a breakthrough [that] is an important step in eventually identifying signs of life on a planet outside our Solar System.

Science/AAAS News:

Astronomers have detected the organic molecule methane in the atmosphere of an extrasolar planet for the first time and have confirmed earlier observations of water vapor. Alas, the findings don't come close to suggesting that life has emerged on this other world, but they do contribute to a growing body of data about planetary evolution outside our own solar system.

Co-author Mark Swain of NASA's Jet Propulsion Laboratory in Pasadena, California, emphasized that HD 189733b is far too hot--average atmospheric temperature about 1000°C--to support life as we know it. But the presence of methane raises intriguing questions, he said, because the high temperature should have sequestered all of the carbon in the planet's atmosphere in the form of carbon monoxide (CO), not methane (CH4). That suggests a currently unknown chemical process is at work, he said.

Physics & Space Science

Source

http://sciencenow.sciencemag.org/cgi/content/full/2008/319/2

http://www.esa.int/esaSC/SEMTZ1N5NDF_index_0.html

GRAVITAS: Portraits of a Universe in Motion

Matt Daniels — Wed, 27 Feb 2008 09:37:56 -0800

NOTE: This content was aggregated from RSS feed. Original source is http://arxiv.org/abs/0802.3664

GRAVITAS: Portraits of a Universe in Motion
Authors: John Dubinski, John Kameel Farah
(Submitted on 25 Feb 2008)

GRAVITAS is a self-published DVD that presents a visual and musical
celebration of the beauty in a dynamic universe driven by gravity. Animations
from supercomputer simulations of forming galaxies, star clusters, galaxy
clusters, and galaxy interactions are presented as moving portraits of cosmic
evolution. Billions of years of complex gravitational choreography are
presented in 9 animations - each one interpreted with an original musical
composition inspired by the exquisite movements of gravity. The result is an
emotive and spiritually uplifting synthesis of science and art. The GRAVITAS
DVD has been out for two years now but I am now making the DVD disk image
freely available for personal and educational use through a bittorrent
download. Download and burn at your leisure. The animations are also
downloadable in various video formats.

Check it out!
http://www.galaxydynamics.org/gravitas.html

Physics & Space Science

Modified Newtonian Dynamics in Galactic Rotation as an Alternative to "Dark Matter"

Matt Daniels — Mon, 18 Feb 2008 21:34:35 -0800

Description

A simple definition of MOND from Wikipedia:

In physics, Modified Newtonian dynamics (MOND) is a theory that proposes a modification of Newton's Second Law of Dynamics, to explain the galaxy rotation problem. When the uniform velocity of rotation of galaxies was first observed, it was unexpected because the Newtonian theory of gravity predicted that objects that are farther out will have lower velocities. For example, planets in the Solar System orbit with velocities that decrease as their distance from the Sun increases. The MOND theory explains the observed revolution curves, by suggesting that the acceleration of a particle is not linearly proportional to the force, at low values of acceleration. This theory does not have wide support among the scientific community, who currently prefer the alternative dark matter theory. This assumes that a halo of dark matter surrounds each galaxy, causing all the stars in the galaxy disc to orbit with the same velocity.

Personally (editorial), the dark matter hypothesis seems to be gathering a lot more evidence and have a lot more buy-in...

Physics & Space Science

Source

http://en.wikipedia.org/wiki/Modified_Newtonian_dynamics

Amateur satellite spotters

Alex Soojung-Kim Pang — Mon, 04 Feb 2008 19:31:34 -0800

Description

The New York Times reports on amateur "satellite spotters who, needing little more than a pair of binoculars, a stop watch and star charts, uncover some of the deepest of the government’s expensive secrets and share them on the Internet."

Thousands of people form the spotter community. Many look for historical relics of the early space age, working from publicly available orbital information. Others watch for phenomena like the distinctive flare of sunlight glinting off bright solar panels of some telephone satellites. Still others are drawn to the secretive world of spy satellites, with about a dozen hobbyists who do most of the observing....

John E. Pike, director of GlobalSecurity.org, a private group in Alexandria, Va., that tracks military and space activities, said the hobbyists exemplified fundamental principles of openness and of the power of technology to change the game.

“It has been an important demystification of these things,” Mr. Pike said, “because I think there is a tendency on the part of these agencies just to try to pretend that they don’t exist, and that nothing can be known about them."...

The Visual Satellite Observers Web site (http://www.satobs.org/satintro.html) describes the appeal of satellite spotting this way:

Amateur astronomers seeking new challenges, find that spotting faint, rapidly moving satellites, such as the tiny Vanguard 1 (America's second satellite), are comparable to spotting a distant galaxy. Tracking down a newly launched spy satellite in a secret orbit, tests analytical as well as observational skill. Observing the International Space Station transit the sun, moon or one of the planets, requires planning, perseverance, and often a bit of luck.

However, according to the Times, "The government’s relationship with the hobbyists is not a comfortable one. "

Spokesmen for the National Reconnaissance Office have stated that they would prefer the hobbyists not publish their information, and suggest that foreign countries try to hide their activities when they know an eye in the sky will be passing overhead.

The satellite spotters acknowledge that this may be so, though they doubt that such tactics are effective.... Mr. Pike said the officials who complained about the hobbyists “don’t like it, but they’ve got to lump it.” Despite the many clever ways that the spy agencies try to minimize the likelihood that their satellites will be spotted, he said, they will be. And that, he said, is a valuable warning: a world with so many eyes on the skies renders deep secrets shallow.

Amateur, DIY, and citizen science

Source

http://www.nytimes.com/2008/02/05/science/space/05spotters.html?_r=1&hp&oref=slogin
http://www.satobs.org/satintro.html

NASA Finds Direct Proof of Dark Matter: August, 2006

Matt Daniels — Thu, 31 Jan 2008 09:42:10 -0800

Description

Galactic Collision
NASA Finds Direct Proof of Dark Matter:
(August 21, 2006)

Dark matter and normal matter have been wrenched apart by the tremendous collision of two large clusters of galaxies. The discovery, using NASA's Chandra X-ray Observatory and other telescopes, gives direct evidence for the existence of dark matter.

"This is the most energetic cosmic event, besides the Big Bang, which we know about," said team member Maxim Markevitch of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

These observations provide the strongest evidence yet that most of the matter in the universe is dark. Despite considerable evidence for dark matter, some scientists have proposed alternative theories for gravity where it is stronger on intergalactic scales than predicted by Newton and Einstein, removing the need for dark matter. However, such theories cannot explain the observed effects of this collision.

IFTF Workshop January 31, 2008

Source

http://chandra.harvard.edu/press/06_releases/press_082106.html

China building two of the world’s largest telescopes

Philip Cho — Wed, 16 Jan 2008 07:12:50 -0800

Description

Under the National Major Scientific Projects program, the Chinese Academy of Sciences is building both the world’s largest spectroscopic and radio telescopes. With an investment of 230 million yuan, the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is a quasi-meridian reflecting Schmidt telescope with an optical axis fixed in the meridian plane. LAMOST will have an aperture of 4m, focal length of 20m, and focal plane of 1.75m giving it a 5 degree field of view containing approximately 4,000 optical fibers. The telescope will have the highest spectrum acquiring rate in the world and provide Chinese researchers cutting edge facilities for large scale observation of optical spectra and wide field astronomy important for studying the evolution of galaxies and the early universe. The project is near completion and will begin operation next year.

In 2007, the CAS also set aside 600 million yuan for the next 6 years to construct the Five-hundred-meter Aperture Spherical Telescope (FAST), surpassing the US’s 305m Arecibo in Puerto Rico as the world’s largest radio telescope. The receiving dish will be composed of 4,600 triangular panels suspended in a limestone karst depression in southwest Guizhou Province.

Both telescopes will of course be major assets for basic research in galaxy formation, pulsars and the early universe. They will also be important for China’s ambitious space programs, and more generally symbolize China's ambitions to move into the front ranks of global science. However, the Field of Dreams mentality of, “If you build it, they will come” may run into problems concerning fixed operating budgets. Building world-class facilities does not necessarily translate into producing world-class research, especially without the flexibility to fund innovative research that central planners had not foreseen.

http://www.bao.ac.cn/index_cn.asp#
LAMOST：http://www.lamost.org/xoops/
FAST：http://www.cas.ac.cn/html/Dir/2004/07/30/6959.htm
http://tech.enorth.com.cn/system/2007/08/02/001799835.shtml

Signals

Using satellites to comb for exoplanets and earth-like worlds

Matt Daniels — Tue, 04 Dec 2007 14:36:57 -0800

Description

An extrasolar planet, or exoplanet, is a planet outside our Solar System. Although evidence for 268 planets has been found around 260 other stars (as of December, 2007)[1], so far no one has been able to get a good look at any of them. The study of planets orbiting other stars is one of the most exciting areas of astrophysics today. Most exoplanets have been detected so far through 'indirect' observation -- spectroscopy measurements of parent stars which indicate planetary motion-induced "wobbling" -- rather than direct observation.

With a critical mass of theorists and attention in this area, satellite missions are being planned to find more planets that transit in front of their parent stars (from our vantage point) and enable astronomers to collect unusually rich data on their mass, atmosphere and other features. Transiting planets in particular yield a wealth of information: the depth of the dip in the light curve gives the size of the planet, and the fact that the orbit must be edge-on nails down the actual mass. Together the mass and radius yield the density and surface gravity. Spectroscopy during transit can provide information about the composition of the atmosphere. For only fourteen exoplanet candidates, a slight drop in the light from the parent star has been detected, indicating that the companion is actually a planet[2]. One planned mission, the Transiting Exoplanet Survey Satellite (TESS), hopes to locate as many as a thousand such 'transiting' systems -- these could be followed up on for more detailed study by later space telescopes.

Many think the field of exoplanet observation will progress quickly as a multitude of new projects push the technological envelope. For the first 'image' though, at least one person is willing to make a prediction:
"I think we are very close to having a picture of an exoplanet - maybe even within two years ... it's a race." (Ben Oppenheimer, American Museum of Natural History in New York) [3].
This may be a bit optimistic (depending on whom you talk to), but it is at least indicative of the rate at which the field is advancing.

Primary methods for detecting extrasolar planets:

Doppler spectroscopy ("wobble method"): Measures slight changes in position of star due to planetary orbit. Changes in direction can be detected by measuring the location of spectral emission lines in the star's light. By far the most successful method for detecting the effects of exoplanets.

Astrometry: Detecting similar movement of a star, using precise knowledge of background stars for reference.

Transit method: Measuring a dip in relative luminosity of a star as a planet (presumably) passes in front of the star.

Optical detection: Directly observing a planet, using a coronograph or interferometric methods to diminish the star's light.

The greatest impact: significantly increased fundamental understanding of planetary systems

Key questions that might be impacted:
Are terrestrial planets common or rare?
What are their sizes & distances?
How often are they in the Habitable Zone?
What are their dependencies on stellar properties?

Habitable Zone

[1] NASA Planet Quest

[2] Transiting Exoplanet Survey Satellite (TESS) information sheet.

[3] "Instrument to Unveil New Worlds by Blocking Out Starlight," NASA Lyot Project

[4] Wikipedia, Extrasolar Planets

[5] The first paper: Campbell, B.; Walker, G. A. H.; Yang, S. (1988). "A search for substellar companions to solar-type stars". Astrophysical Journal, Part 1 331: 902 – 921.

Signals

Instrument to Unveil New Worlds by Blocking Out Starlight

PlanetQuest: Exoplanet Exploration

Understanding dark matter and its place in the universe

Matt Daniels — Mon, 12 Nov 2007 09:18:36 -0800

Description

Progress is likely to be made in understanding the nature and effects of dark matter in our galaxy and elsewhere in the universe.

Most of the mass of our galaxy is dark matter -- the composition and origin of which is currently unknown. Objects known to us (humans, oceans, planets, stars) comprise less than 4% of the total mass of the universe. While ordinary matter determines gravity in our immediate neighborhood, therefore, dark matter controls the dynamic behavior of large objects, such as galaxies and superclusters of galaxies.
Cosmological Composition
Related to this strange situation is a second mystery: the presence of an invisible dark energy separate from dark matter, the gravitational force of which is repulsive, causing our universe to expand at an accelerating rate. The presence of these three key components of our universe (ordinary matter, dark matter, and dark energy) is not explicable by any current insight or theory. Improved theories regarding the total mass of the universe, therefore, have lent a fundamental significance to studies of 'dark matter.'

Given the current inability to observe directly dark matter, indirect observations through the measurement and quantification of galactic rotation present the most frequently-used methods for indicating the presence of non-luminous matter. Vera Rubin was one of the first to observe that the distribution of mass in many spiral galaxies does not necessarily correspond to either visible morphology or the distribution of luminous matter; she accomplished this through the use and study of galactic rotation curves (Rubin, 1985).

Studies of dark matter will clearly be important well into the future. New ways of detecting dark matter are also becoming available – such as observations of gravitational lensing to compare the total versus luminous mass of star clusters and other large objects (Rubin, 1998). As new methods for indirectly detecting dark matter increase in number, a correlated occurrence of attempts to put constraints on the nature of dark matter also increase. The current most widely-held theory for dark matter, for example, proposes the existence of massive exotic particles, which interact with normal matter only through gravitational forces (Clery, 2006).

It seems worth noting that even with substantial contributions since Vera Rubin's original work on the subject, establishing constraints on the nature of dark matter, before methods for direct observation and hypothesis-testing are available, will be approached with a fair degree of conservatism. This opens even greater importance, however, for further investigations into the subject.

This will be enabled by:
--Continuation and expansion of work by high-resolution optical, infrared, Radio, and X-ray observatories as well as high-energy particle detectors
--Continuing observation of radio emissions and cosmic background noise
--Advances in theoretical cosmology

Initial indicators include:
--Observations, from the structure and dynamics of galaxies, that in most galaxies the majority of mass consists of non-luminous matter (matter that neither emits nor absorbs radiation), rather than better-understood stars and nebulae

What to watch:
--Direct “observations” of dark matter, through effects such as gravitational lensing
--Theoretical breakthroughs leading to more accurate inference from optical observations.

Significantly improved cosmological models & understanding of universe
Improved ability to predict cosmic events
Possible discovery of new states of matter
Possible modification of general relativity

* Clery, Daniel. 2006, Science, 311, 758.
* Rubin, Vera. 1980, Astrophysical Journal, 238, 471.
* Rubin, Vera. 1985, Astrophysical Journal, 297, 423.
* Rubin, Vera. 1998, Scientific American (Special Edition Cosmos), 9, 106.
* Board on Physics and Astronomy, Connecting Quarks with the Cosmos: Eleven Science Questions for the New Century (2003) Link
* Horizon: Most of Our Universe is Missing BBC TV (broadcast 9 Feb. 2006) Link
* Pedro F. González-Díaz, "You need not be afraid of phantom energy", Physical Review D, 68, 021303 (R), Link
* Geoff Brumfiel, "Cosmology Gets Real," Nature 422, 108-110, 2003, Link
* J I Davies et al, "The Existence and Detection of optically dark galacies by 21cm surveys," Monthly Notices of the Royal Astronomical Society, 2005 Link

Signals

NASA Finds Direct Proof of Dark Matter: August, 2006

Understanding Dark Energy [draft]

Alex Soojung-Kim Pang — Tue, 23 Oct 2007 11:10:30 -0700

Description

Progress is likely to be made in understanding the dominance of dark energy in our universe.

Our universe is composed primarily of dark energy, the nature of which is not currently understood.

The objects known to us as ordinary matter (humans, oceans, planets, stars) comprise less than 4% of the total mass of the universe. While ordinary matter determines gravity in our immediate neighbourhood, dark matter controls the dynamic behavior of large objects, such as galaxies and superclusters of galaxies.

Related to this strange situation is a second mystery: the presence of an invisible dark energy separate from dark matter – the gravitational force of which is repulsive, causing our universe to expand at an accelerating rate.

The presence of these three key components of our universe (ordinary matter, dark matter, and dark energy) is not explicable by any current insight or theory.

This will be enabled by:
-Continuation and expansion of work by optical, infrared, Radio, and X-ray observatories as well as high-energy particle detectors
-Continuing observation of radio emissions and cosmic background noise
-Advances in theoretical cosmology

Early indicators include:
-Observations of the structure and dynamics of galaxies that have been found to be at odds with the distributions of galactic mass inferred from optical observations

What to watch:
-Theoretical breakthroughs lead to more accurate inference from optical observations.

Signals

Multidisciplinary astrobiology and the quest to find life beyond Earth

Alex Soojung-Kim Pang — Tue, 23 Oct 2007 11:10:29 -0700

Description

[Revising...]

Multidisciplinary efforts by astrobiologists may increase our understanding of the origins of life on this planet and could result in finding biospheres beyond Earth.

Astrobiology, is the study of life in the universe. The field is driven by fundamental questions that have fascinated scientists and lay people for millennia: Where did we come from? Where are we going? Are we alone? Astrobiology is necessarily a multidisciplinary field, drawing from astronomy, genomics, molecular biology, information technology, geology, paleontology, chemistry, physics, astronomy, and planetary science. Through collaborative efforts among these disciplines, scientists hope to understand the origin, evolution, and distribution of life. Astrobiologists start from the assumption that only by dentifying the 'conditions necessary for life to emerge' can scientists know how and where to look for life elsewhere in the universe, especially when habitable environments may be very different from our own home.

Some scientists, notably Jack Cohen and Ian Stewart, reject the term 'astrobiology' and the whole astrobiology programme along with it. For them, talk of 'conditions necessary for life' is both parochial and unimaginative. They dismiss astrobiology as, "the science of Earthlike planets supporting Earthlike life". In place of astrobiology, they speak about 'xenobiology' -- a science that restricts itself less than astrobiology, does not presume to be able to determine the conditions necessary for life and absolutely refuses to discuss 'habitable zones' (regions around stars that are conducive to Earth-type life -- not to hot nor too cold). In general use, the terms are interchangable, but the existence of an emerging coherent field (astrobiology) and a radical opposition to the growing consensus (xenobiology) is significant.

Because scientists have yet to prove the existence of life on other planets, most astrobiology is done on Earth. For example, researchers have been surprised to find life in such extreme environments as incredibly hot volcanic vents in the deep ocean, icy Antarctic lakes, and highly acidic water. These are the kinds of environments that may harbour life elsewhere in the universe, and studying life forms that thrive there opens our eyes to the robustness and adaptability of life. The search for life in the universe continues in biology laboratories too. All life we know about has a similar biochemical basis but it is currently unknown if DNA, etc. is a necessary condition for all life, or just an 'accident' of life on Earth. Attempts to create synthetic life forms will help answer this question. Advances in theoretical biology precipitated by new mathematical approaches are also helping to set the parameters for the search for life beyond Earth.

In our own solar system, scientists have found evidence of water on both Mars and Jupiter's moon Europa. The existence of water is a necessary condition of all life we know, so locations with water may be a good place to start the search for life. In the coming decades, astrobiologists may very well determine whether life exists there or did in the past. Meanwhile, astronomers continue to discover planets outside our solar system, and one of their goals is to find Earth-like planets with chemistry conducive to life as we know it.

The NASA Astrobiology Roadmap outlines seven scientific goals that are expected to be the most fertile ground for exploration in the coming years:

Understand the nature and distribution of habitable environments in the universe
Explore for past or present habitable environments, prebiotic chemistry, and signs of life elsewhere in our solar system
Understand how life originates from cosmic and planetary precursors
Understand how past life on Earth interacted with its changing planetary and solar system environment
Understand the evolutionary mechanisms and environmental limits of life
Understand the principles that will shape the future of life, both on Earth and beyond
Determine how to recognize signatures of life on other worlds and on early Earth

This will be enabled by:

Continued fostering of multidisciplinary science projects
Renewed interest in space exploration, driven by a desire to know if there's life 'out there'
Development of new biological, chemical, and geological tools for analysing samples brought back from space and extreme environments
Development of increasingly advanced telescopes, both terrestrial and space-based
Advances in A-Life that inform theoretical biology
Development of in the laboratory of synthetic micro-organisms
Development of synthetic organisms that use a mechanism other than DNA or RNA to encode information for reproduction

Early indicators include:

1977 discovery of life in hydrothermal vents
Development by James Lovelock of the Gaia Hypothesis from an attempt to determine if there was life on Mars by studying the planet's atmosphere
Discovery of more than 150 exoplanets
Discovery of evidence of liquid water on Europa and possibly Mars
Ongoing development of plans for a manned mission to Mars before midcentury
Founding in 1998 by US NASA of the NASA Astrobiology Institute (NAI), consisting of hundreds of astrobiologists at more than a dozen institutions around the US, from UC Berkeley to Pennsylvania State University to the SETI Institute
Launching of similar large-scale efforts around the world through such NASA partners as the Astrobiology Society of Britain, Australian Centre for Astrobiology, and the Centro de Astrobiologia
Founding of the International Journal of Astrobiology at Cambridge University
Development of A-life (simulated organisms that live in virtual environments)
Application of cellular automata to theoretical biology

What to watch:

New terrestrial planets like Mars and Earth are discovered.

Potential to discover extraterrestial life
Better understanding of the origins of life on Earth, past extinctions, and the possible future of life on this planet
Better understanding of the impact of space environments on human physiology and our own possible future in space
Potential for medical applications of astrobiology tools such as lab-on-a-chip and other bio-assays

Signals

Future of unmanned space exploration

Alex Soojung-Kim Pang — Tue, 23 Oct 2007 11:10:29 -0700

Description

[Revising...]

Improvement in the utility per kg for systems on robotic spacecraft make them increasingly attractive to space agencies for increasing numbers and types of missions.

Even as NASA concentrates its resources on manned lunar and Martian expeditions, unmanned space exploration may find new prominence and greater funding in an effort to replace more costly, less productive science performed on manned missions.

Though ESA's budget ($3.8 billion for FY2005) is roughly a quarter of NASA's ($16 billion for FY2006), ESA's agility and relative lack of legacy programs will help it to achieve more with less funding. Over the coming decade, ESA has concrete plans for unmanned missions to Venus, Mars, Mercury, and in conjunction with the Indian space agency, the moon. ESA will probably use knowledge developed in these programmes, and especially research on new propulsion technologies, to launch even more probes in the years up to 2020 and beyond. Unified platforms and systems of systems will reduce overall costs. Initial probe development promises to beget less expensive probes in the future.

Building upon programmes planned for the 2010 to 2020 timeframe, scientists hope to be able to construct 3D maps of the galaxy, gain a better understanding of the origins of the universe, and search for Earth-like planets. Microsatellites, launched for less than $10 million apiece (for example, Canada's MOST space telescope), will probably play an important role in these discoveries by allowing astronomers more time for otherwise low-priority experiments. Upon its launch around 2011, NASA's James Webb Space Telescope will study the origins of the universe using infrared sensors, if its progress is not hampered by further budget cuts and downsizing.

This will be enabled by:

Expense and inefficiency of scientific experimentation on manned missions

Early indicators include:

Construction by ESA of its Venus Express, using the same platform as the successful Mars Express
Testing of an ion propulsion system by ESA's SMART-1 probe
Wavering by NASA on rehabilitating the Hubble Space Telescope and its lack of planning for a direct replacement
Cutting from NASA's 2006 budget of its Jupiter Icy Moons Orbiter (JIMO), long planned as a testbed for advanced probe technology

What to watch:

An increasing number of scientific papers cite the Hubble Space Telescope rather than the International Space Station.
US cuts funding for deep-space exploration, unmanned programs, and 'blue sky' projects.

Better knowledge of our solar system and those yet unexplored
Potential for discovery of extraterrestrial life
Better understanding of the moments following the Big Bang
Better understanding of the composition and history of Mars, Mercury, and Venus