NICMOS image of the Hubble Deep Field. (Rodger I. Thompson, U. Arizona and NASA/STSCI)
Remember, when you come across a fantastical astronomical (or any other) story in the media, you should examine the evidence carefully and take claims with a grain of salt. An open but skeptical mind is best. You should be just as skeptical about my analysis of them as I am of the stories, and think for yourself!
For 10 days, the Hubble Space Telescope's NICMOS infrared camera stared at the patch of sky known as the Hubble Deep Field (HDF), which was imaged for 10 days in visible light by WFPC2 in 1995. The claim of "most distant galaxies" arises as a number of faint objects are seen in the NICMOS that were not present in the WFPC2 pictures, and thus they fit expectations for popular cosmological models. Note that no distances (ie. redshifts) were actually measured for these galaxies, nor are there likely to be in the future given how faint they are! The NICMOS-HDF, when combined with the WFPC2-HDF, will certainly continue to provide fodder for galaxy evolution studies for years to come, and the Next Generation Space Telescope (NGST) scheduled for a 2007 launch, will be eagerly awaited by astronomers tantalized by this view of the fringe of the Universe at the limits of the current HST capabilities.
NICMOS image of the Hubble Deep Field.
(Rodger I. Thompson, U. Arizona and NASA/STSCI)
Soapbox Editorial: Although these are certainly fantastic images and are likely to provide important clues to galaxy evolution (much as the original HDF images have done), one cannot help but feel a little queasy about the implications that these really are very distant galaxies, given the real lack of supporting evidence. A proper perusal of the actual press release gives a more balanced view, if you actually take the time to read it carefully. Again, it looks like NASA is pushing the envelope, in hype, if not in distance. Its really good work, and I would hate to see it sink under the weight of purple prose. IMHO.
In a May 28 press release, astronomers and NASA officials announced the possible discovery of another extrasolar planet. During an HST observation of a young binary system in the nearby Taurus molecular cloud region, a stellar (point-like) object was seen in the NICMOS image. This was interpreted as the first-ever image of a multi-Jupiter mass planet, this time in the process of being ejected from the binary system. If this explanation is correct, then this is an important step on the way to truly understanding the formation of planetary systems in our galaxy.
However, caution is in order. The only information available is the NICMOS (Near Infrared Camera) image itself, as no spectra are available for this object. You can make your own interpretation from the images - it is clear (from the diffraction pattern seen in the raw images, though hard to see in the press release photos) that there is indeed a stellar object, and there is a filamentary arm, the the stellar object is aligned with it. It is therefore natural to associate the object with the binary system (and thus, given the known distance to the binary, its young age, and the observed brightness, to derived a 2-3 Jupiter mass). But it should be noted that these sorts of juxtapositions were used not so long ago to associate very distant quasars with nearby galaxies, which was touted as evidence for quasars being ejected from galaxies! This was demonstrated to be false, and due to chance superposition and erroneous statistics. One serendipitous observation does not justify this claim, and though it is an intriguing possibility, it should be treated with skepticism. (Some questions: could this be a more distant star? How about dust obscuration? What are the chances of catching the ejected planet given its velocity and distance (compared to the age of the system)? How does this compare to the chance of an unrelated superposed star?)
Still, this shows, along with other recent and better supported discoveries (see below), that we are making great strides toward the understanding of the origins of stars, planets, and life in the Universe. I hope that in its fervor to publicize its Origins program and garner public support, NASA doesnt go too far and trample on the truth. For example, there is concern in the community that this particular press release was made before the paper was submitted for publication, let alone peer-reviewed. This was not made clear to the press or public. Furthermore, some members of the press who upon discovery of this made their unhappiness clear were taken to task by NASA. Badly done, NASA, badly done.
But thats just my opinion, I could be wrong.
In March 1998, we were treated to prognostication of impending doom from above, and then less than a day later assured us that it would be only a near miss. Whats up with this?
Well, its true - the Earth will be hit sometime, and has been in the past. Big impacts seem to occur every 60,000 to 100,000 years, so it would be odd if we were pummeled a mere half century after we began to realize the danger! Still, it is worth keeping an eye on the Earth-Crossing Asteroids. In fact, there is much we still need to know about them, hence the current interest among astronomers.
Of course, calculation of orbits for these inner solar system objects is difficult (this was the main problem leading to the erroneous doomsaying). Perturbations by the Earth, its Moon, and other inner planets cause havoc with the computations. In fact, the orbits may be "semi-chaotic".
On the soapbox: IMHO, it was somewhat irresponsible on the part of those astronomers who originally issued the press release, to make such a big deal of the limited first predictions. It was also somewhat peculiar that a big part of the initial press came from scientists at Los Alamos who may well have an interest in receiving funding for their research and related projects and applying star-wars tech to blowing up asteroids. Badly done.
For more info and related stories:
NASA reported last year that Martian meteorites contain possible microfossils. Much of the recent interest in Mars stems from the discovery of small carbonaceous nodules in a meteorite of Martian origin that may be signs of bacterial life earlier in the planet's history. This evidence is suggestive, though not conclusive, and is currently being disputed by several research groups. As with many difficult problems in science, the debate continues on. It is generally agreed that conclusive evidence one way or another must await a sample return mission in the next decade.
Closeup of Europa's surface, courtesy JPL/NASA
The Galileo spacecraft has been beaming back fantastic images of the satellites of Jupiter as it orbits within the Jovian system. Some of the latest press on the grooved surface of Europa has a flavor of Arthur Clarke's Space Odyssey series about it. Take a look for yourself and see what you think ...
The Hipparcos Satellite, which has measured accurate parallaxes for a large number of stars, has recently produced some results which have refined the distance scale, and more fundamentally, claimed to have brought the ages of globular clusters in line with the expansion age of the Universe as determined by the standard cosmological parameters (Hubble constant and density).
Some preprints related to this topic:
The links to preprints may not work from all sites. Sorry.
Astronomers from the Harvard-Smithsonian Center for Astrophysics have discovered a tiny (300 miles dia.) icy body with an orbit outside that of Pluto. It is not clear whether to classify this as a cometary object, or a planetoid. There are likely to be a large number of other such objects, also made mostly of volatiles like water ice, in the cold outer reaches of our solar system.
For a number of years now, Prof. Louis Frank of the University of Iowa has claimed that observations using instruments on board Earth-orbiting satellites have shown that our planet is being continuously bombarded by small ice comets. Over the course of billions of years, these would have provided the water in our oceans and thus the key to life. Crazy? It certainly has received some skepticism and ridicule in the scientific circles.
Actually, this is surprising close to our "standard" picture of the deposit of volatiles, the hydrosphere and atmosphere, on a terrestrial planet. Early in its history, the Earth would have been extremely hot, and any indigenous water would have likely boiled away, along with gases. As far as I know, the best theory for the origin of our oceans and atmosphere is that cometary objects during the period of intense bombardment (that cratered the moon for example) brought them to Earth. It would be natural then to observe a residual bombardment, just like we still observe occasional asteroid and meteoroid bombardment. The fact that water has been found on the moon supports this also.
See the CNN story for more details.
A new satellite, combined with ground-based optical and radio measurements, may have discovered the "smoking gun" that will identify the source of the mysterious Gamma-Ray Bursts (GRBs).
In a May 14 press release, a team of Caltech astronomers has reportedly clinched the identification of the source of the mysterious gamma-ray bursts (GRBs) as cosmological - originating in distant galaxies as opposed to in our own galaxy or in the outer reaches of our solar system as some competing models would have it. The identification of spectral features and determination of its redshift, and hence distance, is the smoking gun for a cosmological origin model.
The leading model for the origin of these bursts is a merger between two neutron stars (or perhaps black holes) where because of the liberation of vast amounts of gravitational potential energy the object can outshine an entire galaxy for a short time. Note that a supernova, due to the core collapse inside a massive star, is powered by graviational binding energy also (though the luminosity comes from a different mechanism).
It really looks like these observations have hit the target. Note that there is a whole network of supporting observations here, not just one "fantastic" claim. This is how science works at its best, with predictions and confirmations between independent scientists and teams.
Some links:
The Comption Gamma Ray Observatory is a satellite that was launched in 1991 and has been observing the sky at the extremely short wavelength of gamma-ray light that is produced in some of the most energetic events in the Universe.
This last week (28Apr97) it was reported that clouds of "antimatter" have been found in the direction of the galactic center. This in itself is only mildly surprising, since it has long been believed that "jets" of electron-positron (anti-electron) pairs are produced and accelerated by supermassive black holes like that believed to be at the center of our own galaxy. What is surprising about this is the most confusing way this report has been presented to the media. I am having a hard time figuring out exactly what is going on, but my guess is some annhililation lines (at 511 keV, the mass-energy of the electron) is seen the the GRO data. Have to wait for the paper I guess.
Some links to this story and related sites:
This is one of the more annoying stories to hit the news lately. These two physicists publish a paper in the journal Physical Review Letters (after several years of trying to get it past referees according to rumor), push it in the New York Times, and within a week of the hoo-ha there are several refutations appearing on physics bulletin-boards. This was, in my humble but unfavorable opinion, a truly shoddy analysis of data. One of the authors says "We never know, right?" - I guess he doesn't.
The jist of the claim was that there is some preferred direction in the sky, which manifests itself in a correlation of angles of polarization of radio emission in distant radio galaxies. It should be pointed out that this sort of funny business is predicted by the authors' own pet theory, which isn't mentioned in the news articles I've seen by the way. The authors took archival data and did a "statistical" analysis on it. It was the statistical analysis that was faulty, and I should point out that looking for this effect is a reasonable test to make on the universe. It is just that if a correct analysis is done, as has been pointed out in a counter-paper, no such signal is seen.
I should make it clear that it is not the claim of a discovery that challenges the orthodoxy that is the problem - this is the way science progresses after all - but the lack of careful analysis and the failure of the refereeing process that are worrisome. However, in the end (within a week in fact), the truth wins out.
Some links to the tempest in a teapot:
The links to preprints may not work from all sites. Sorry.
The SOHO spacecraft detected a large solar flare, which impacted the Earth late Wednesday April 9. It was small enough that communications were not significantly disrupted. This flare is part of the increase in solar activity associated with the 11-year solar cycle. SOHO will be in good position to study solar activity over the next cycle.
For coverage and further details (as well as a fascinating glimpse into how a science story progresses in the media :)
Astronomers are now debating whether the extrasolar planetary system candidate 51 Pegasi is indeed a 4 day period binary with a planetary mass companion, or a bizarre example of a pulsating star. The star 51 Pegasi is perhaps the strangest example of a planetary system, since the period is only around 4 days, which implies an extremely close orbit yet a companion the size of a large gas-giant (like Jupiter). See the CNN coverage of the debate.
Some extrasolar planet links:
I should mention that I think the CNN online news site is great. As you see I link to it alot. Their cross-links also are useful, and surpass what the print media can do in background material. I would like to see more follow-up, but the CNN online does a much better job than the NYT for example where you are alway left wondering "what ever happened to ...". The CNN reporting is pretty high quality also.
Kudos to CNN.
Today's Sci-Tech news from CNN
A back-listing of some CNN Sci-Tech highlights:
Scientists again dispute meteorite claim (CNN 1/16/98)
Asteroid Imact killed dinosaurs?
Black holes do exist?
A grim end to the Universe?
Solar Flare kills satellite!
The press releases from NASA are a special case. There are indeed truly exciting results being uncovered by the numerous satellites, space probes, shuttle missions, and in particular the wonderful Hubble Space Telescope. However, it must be understood that the press releases not only serve the purpose of sharing the excitement with the public, but to propagandize and keep up support for these endeavours. The press releases are not intended to be evenhanded, objective accounts of the results, but to present these with the most positive spin they can.
Again, keep an open mind, and be skeptical. This is mostly really good stuff, but the actual impact of the research on the field is often somewhat exaggerated.
Today @ NASA - press releases from NASA HQ
The latest images
and Press
Releases from Hubble Space Telescope
smyers@nrao.edu Steven T. Myers