In silhouette against a crowded star field toward the constellation Scorpius, this dusty cosmic cloud evokes for some the image of an ominous dark tower. In fact, clumps of dust and molecular gas collapsing to form stars may well lurk within the dark nebula, a structure that spans almost 40 light-years across this gorgeous telescopic portrait. Known as a cometary globule, the swept-back cloud, extending from the lower right to the head (top of the tower) left and above center, is shaped by intense ultraviolet radiation from the OB association of very hot stars in NGC 6231, off the upper edge of the scene. That energetic ultraviolet light also powers the globule’s bordering reddish glow of hydrogen gas. Hot stars embedded in the dust can be seen as bluish reflection nebulae. This dark tower, NGC 6231, and associated nebulae are about 5,000 light-years away.
Here’s the Earth, the Solar System, our galaxy, our local group of galaxies, our local group of groups of galaxies, our local group of groups of groups of galaxies, and the observable universe, compared:
(Click for large version.)
Always takes a while to sink in. So hard to fathom!
Kudos to the U.S. congress. Its members can propose legislation that gives a trillion dollar tax break — that’s $1,000,000,000,000 — to the richest 1% of the population, but they can’t spend $5 million on keeping one of the most hopeful — and, potentially, one of the most important — scientific pursuits in the history of humankind alive.
Carl Sagan would be so disappointed.
The timing couldn’t be worse, say SETI scientists. After millenniums of musings, this spring astronomers announced that 1,235 new possible planets had been observed by Kepler, a telescope on a space satellite. They predict that dozens of these planets will be Earth-sized — and some will be in the “habitable zone,” where the temperatures are just right for liquid water, a prerequisite of life as we know it.
Just knowing SETI is there was significant for us. This is a setback.
If we miss a distant signal, it would be a terrible loss.
– Sarah Wiehe
All stars emit visible light, and Sun-like stars emit most of their electromagnetic radiation in the visible part of the spectrum. Sensing light is a much more effective way of understanding the environment at some distance; certainly much more powerful than olfactory cues. It’s hard to imagine a competent technical civilization that does not devote major attention to its primary means of probing the outside world. Even if they were mainly to use visible, ultraviolet or infrared light, the physics is exactly the same for radio waves; the difference is merely a matter of wavelength.
I do not insist that the above arguments are compelling, but neither are the contrary ones. We have not witnessed the evolution of biospheres on a wide range of planets. We have not observed many cases of what is possible and what is not. Until we have had such an experience–or detected extraterrestrial intelligence–we will of course be enveloped in uncertainty.
The notion that we can, by a priori arguments, exclude the possibility of intelligent life on the possible planets of the 400 billion stars in the Milky Way has to my ears an odd ring. It reminds me of the long series of human conceits that held us to be at the center of the universe, or different not just in degree but in kind from the rest of life on Earth, or even contended that the universe was made for our benefit. Beginning with Copernicus, every one of these conceits has been shown to be without merit.
In the case of extraterrestrial intelligence, let us admit our ignorance, put aside a priori arguments, and use the technology we are fortunate enough to have developed to try and actually find out the answer. That is, I think, what Charles Darwin–who was converted from orthodox religion to evolutionary biology by the weight of observational evidence–would have advocated.
– Carl Sagan
We conclude that skepticism regarding SETI is at best unfounded and at worst can seriously damage the long-term prospects of humanity. If ETIs exist, no matter whether friendly or adversarial (or even beyond such simple distinctions), they are relevant for our future. To neglect this is contrary to the basic tenets of transhumanism. To appreciate this, it is only sufficient to imagine the consequences of SETI success for any aspect of transhumanist interests; and then to affirm that such a success can only be achieved without trying if they come to us, which would obviously mean that we are hopelessly lagging in the race for Galactic colonization.
We find a streak of very subtle anthropocentrism hidden in the usual understanding of the “Great Filter”. Seemingly, we are led into a dilemma: either we are optimists about extraterrestrial life and SETI or we are optimists about our particular (human/posthuman) future. We find the dilemma false and a bit hypocritical, like all man-as-the-measure-of-all-things argument from Protagoras to this day. We can have both of the alternatives above; we can be optimists about life and intelligence in general. And only future astrobiological research can persuasively show to which degree our optimism in both directions is justified.
As all who have ever tackled this question agree, investments in SETI are invariably a minuscule fraction of any civilization’s scientific investments. Even the cost of the most ambitious SETI projects imagined so far (like CYCLOPS; see Oliver 1973) is negligible in comparison to such endeavors generally regarded as desirable and worthwhile like the development of artificial intelligence, setting up efficient defense against impacts, or building O’Neill colonies (not to mention more ambitious projects, like terraforming or uplifting of stellar matter). Thus, there is no real economic excuse for neglecting this field, as well as the general astrobiological enterprise, once prejudices and fallacious arguments are rejected. At least this argument applies as long as it is really necessary to influence public opinion at large to support this type of scientific research; it is to be hoped that in future rich societies such research could be performed by individuals even if the majority still continues to consider them irrelevant or even undesirable.
Of course, all this pertains to a long-term view. No theoretical model can guarantee the success of SETI on short timescales, certainly not on the scale of a present-day human lifetime. But, a healthy admixture of long-term views and long-term planning seems inescapable if we wish to leave to our descendants a prospect of living under the billion suns of the Milky Way.
– Milan M. Ćirković
Icelandic photographer Örvar Atli Þorgeirsson has been capturing some mesmerizing pictures of Iceland’s beautiful ice structures and auroras. You’ve probably seen the terrifying Pictures of Eyjafjallajökull, but get a load of these:
All images credit and copyright Örvar Atli Þorgeirsson.
Well over a thousand galaxies are known members of the Virgo Cluster, the closest large cluster of galaxies to our own local group. In fact, the galaxy cluster is difficult to appreciate all at once because it covers such a large area on the sky. Spanning about 5x3 degrees, this careful mosaic of telescopic images clearly records the central region of the Virgo Cluster through faint foreground dust clouds lingering above the plane of our own Milky Way galaxy. The cluster’s dominant giant elliptical galaxy M87, is just below center in the frame. Above M87 is the famous interacting galaxy pair NGC 4438, also known as The Eyes. A closer examination of the image will reveal many Virgo cluster member galaxies as small fuzzy patches. Sliding your cursor over the image will label the larger galaxies using NGC catalog designations. Galaxies are also shown with Messier catalog numbers, including M84, M86, and prominent colorful spirals M88, M90, and M91. On average, Virgo Cluster galaxies are measured to be about 48 million light-years away. The Virgo Cluster distance has been used to give an important determination of the Hubble Constant and the scale of the Universe.