Things in Space that Shouldnt Be
A history of astronomy and a history of surprise discoveries in space would track pretty well. Recent stories show that the trend continues even today.
- Wet moon: The moon was thought to be depleted of volatiles – until now. According to PhysOrg, “Researchers discover water on the moon is widespread, similar to Earth’s.” Shouldn’t all this have been known since the Apollo astronauts brought back rocks from the moon? Well, researchers at the University of Tennessee in Knoxville have re-analyzed some samples and are “once again turning what scientists thought they knew about the moon on its head,” the article exclaimed.
They don’t mean they found lakes and oceans there (despite the Latin root for Mare, ocean). Instead, they detected molecular water elements or “lunar dew” in apatite similar to amounts in Earth basalts. Their paper, published in Nature,1 said, “Here we report quantitative ion microprobe measurements of late-stage apatite from lunar basalt 14053 that document concentrations of H, Cl and S that are indistinguishable from apatites in common terrestrial igneous rocks.”
What does this mean? “One possible implication,” the abstract stated, “is that portions of the lunar mantle or crust are more volatile-rich than previously thought.” And if volatiles are rich, the leading theory for the moon’s formation becomes poor. PhysOrg explained:
The finding of volatiles on the moon has deep implications for how it, and the Earth, formed. It is generally believed that the moon was created when the early Earth was hit by a Mars-sized proto-planet called Theia, melting and vaporizing itself and a large chunk of the Earth. The cloud of particles created by the impact later congealed to form the moon, which supposedly was devoid of highly volatile elements such as hydrogen and chlorine. However, the researchers’ discovery of these volatiles challenges this theory.
“If water in the Moon was residue water kept during the giant impact, it is surprising that water survived the impact at all because less volatile elements, such as sodium and potassium, are strongly depleted. The details of the impact theory need to be re-examined,’ [Yang] Liu [U Tennessee] said.
Theia appears poised to join Nemesis in the arsenal of imaginary terrorists (see 07/21/2010).
- Mercurial sleeper awakes: “Every time we’ve encountered Mercury, we’ve discovered new phenomena.” That’s PhysOrg quoting says MESSENGER principal investigator Sean Solomon [Carnegie Institution]. “We’re learning that Mercury is an extremely dynamic planet, and it has been so throughout its history.”
That’s a very different picture than a few years ago, when Mercury was supposed to be a dead world, long ago frozen into silence. Solomon was remarking about Mercury’s young volcanism, magnetic substorms and ionic emissions from its thin atmosphere, discovered during two previous flybys. The spacecraft will go into orbit around Mercury next March: “we’ll be in for a terrific show,” remarked Solomon.
See the pictures on BBC News about the youngest volcano found on Mercury so far. Science Daily surveyed the most surprising finds, and National Geographic News focused on huge “curious” power surges detected in the planet’s atmosphere. “There’re some things here we clearly do not understand,” said one scientist.
- Quakers in space: Ever heard of spacequakes? Those are impacts of plasma blobs from the sun on the Earth’s magnetic field. Big ones can push the field all the way down to Earth’s surface, Space.com said, then they bounce like a tennis ball with decreasing amplitude. The THEMIS spacecraft “discovered something new and surprising” in this “long suspected” phenomenon, the article said: “The surprise is plasma vortices, huge whirls of magnetized gas as wide as Earth itself, spinning on the verge of the quaking magnetic field.”
There are other quakers that have been discovered in space, too. “Spacequakes aren’t the only unearthly temblors around,” Space.com said. “Scientists have also discovered starquakes (violent trembling inside stars), moonquakes and asteroid quakes (seismic tremors on the surface of the moon and asteroids, respectively).” Whole lot of shaking going on out there.
- Rings and hexagons: Scientists from the Cassini mission orbiting Saturn shared a 6th anniversary CHARM teleconference this week (Cassini-Huygens Analysis and Results from the Mission). Two Powerpoint presentations about the rings and atmosphere are available for download in PDF form (audio files may be posted later on). An account of the number of surprises and phenomena not understood in the 100+ slides is left as an exercise; as teasers, they admitted that the B-ring edge is more dynamic and complex than can be understood (ditto for the F-ring), the rings may be much younger than Saturn, and the hexagon-shaped cloud pattern at Saturn’s north pole can only partially be modeled in the lab (audio is needed for full discussion).
- Super star: According to theory, stars can only grow to about 150 times the mass of the sun, partly because they would burn out too quickly to be seen, partly because the winds would tear them apart, and partly because there is not enough gas and dust in most locales to gravitationally contract into a star much bigger than 150 solar masses.
Doubters, behold R136a1: a blue giant almost twice the theoretical size limit. It is currently 265 times the sun’s mass, but astronomers estimate at birth it was a whopping 320 solar masses. And talk about sunburn: its luminosity has been estimated at 10 million times brighter than our sun. The BBC News said its radius is 30 times greater than our sun. A diagram on National Geographic News illustrates the size difference.
Science Daily described the puzzle of this star: “Understanding how high mass stars form is puzzling enough, due to their very short lives and powerful winds, so that the identification of such extreme cases as R136a1 raises the challenge to theorists still further.” Was it born big, or did it collect smaller stars into its household? Astronomers were “really taken aback” by the discovery, National Geographic said, adding: “The discovery could rewrite the laws of stellar physics, since it’s long been thought that stars beyond a certain mass would be too unstable to survive.”
- The big burst: Gamma ray bursts have been known since 1967, but an “extraordinary” one detected on June 21 was off the charts. National Geographic News said that “Until now, scientists thought the brightest gamma-ray bursts sent out a maximum of 10,000 x-ray photons a second.” Here’s the measured flux from this one: “145,000 photons a second… making this gamma-ray burst 10 to 15 times brighter than anything previously seen by Swift’s x-ray telescope. It was so bright it “blinded” the Swift orbiting space telescope temporarily, saturating its detectors: the “rush of light from a minute-long gamma-ray burst proved so overwhelming that Swift’s data processing software temporarily shut down.”
Swift normally catches light from about two gamma ray bursts per week. Space.com said this super-bright one is stirring theories: “Just when we were beginning to think that we had seen everything that gamma-ray bursts could throw at us, this burst came along to challenge our assumptions about how powerful their X-ray emissions can be,” said Neil Gehrels, principal investigator for Swift.
A new mission named Xenia is being planned to watch for these cosmic beacons. “The newfound burst, he said, means that Xenia mission designers will have to go back to the drawing board to make sure the probe will be able to handle the brightest flashes the universe can dish out.” And speaking of explosions, Science Daily reported earlier this month that among the best-understood ones, Type 1a supernovae, the “Origin of Key Cosmic Explosions [Is] Still a Mystery.”
There’s no indication that the number of surprising discoveries will decrease over the next few years. Quite the contrary; an article on PhysOrg about early results from the Herschel Space Observatory with its SPIRE camera quoted Ian Smail of Durham University, who analyzes results from the mission: “It is already clear that we live in a changing Universe and, thanks to Herschel and SPIRE, few things are changing faster than our perception of it.”
Looking back over 400 years of astronomy since Galileo and Kepler, Joseph Burns of Cornell University surveyed the many surprising discoveries made in space, especially in the last 5 decades of the space program: the Van Allen belts; Venus’s young surface; old, cold moons that proved surprisingly active; old, cold comets that showed evidence of hot formation; asteroids thought to be hard rock that turn out to be rubble piles; remarkable dynamism in Saturn’s rings; chaotic motions of moons; and more. “Few scientists envisaged that the neighbouring worlds explored by space missions would be so diverse, nor how entrancing many are.” Publishing his account in Nature,2 (see also summary on Space.com), using the word “surprising” a number of times, he quoted a character from Tom Stoppard’s novel Arcadia in his conclusion talking about scientific revolutions: “It’s the best possible time to be alive, when almost everything you thought you knew is wrong.”
1. Boyce, Liu et al, “Lunar apatite with terrestrial volatile abundances,” Nature 466, pp 466�469, 2 July 2010, doi:10.1038/nature09274.
2. Joseph Burns, “The four hundred years of planetary science since Galileo and Kepler,” Nature 466, pp 575�584, 29 July 2010, doi:10.1038/nature09215.
If some scientists want to celebrate their ignorance, some of us will be happy to supply the conical hats and party blowers. To Joe’s list we can add many more surprises that, within the living memory of many of us, hit the astronomers broadside: quasars, pulsars, blazars, gamma-ray bursts, the cosmic microwave background radiation (partly predicted, but not to the expected values; see 06/12/2008), mature galaxies at the farthest distances (04/02/2009), gravitational lenses (partly predicted), silence from SETI, transient lunar phenomena, Io’s volcanoes, the Enceladus geysers, the inhospitable surfaces of Venus and Mars (civilizations were expected there into the 1960s), Ganymede’s magnetic field, the Kuiper belt, minor planets beyond Pluto, the lack of organics and carbonates (and life) on Mars, the tilted magnetic fields of Uranus and Neptune, the rings of Jupiter and Uranus and Neptune, the F-ring of Saturn, the geysers of Triton, binary asteroids… where could we stop? It’s hard to find any object in space that closely matched what astronomers expected. While we share the thrill of surprising discoveries with the astronomers, we should not treat them as prophets. They have a lot of whiz at math (01/08/2010) and access to great equipment (12/08/2009), but are as fallible as the rest of us – though occasionally, the luck of discovery comes to the prepared minds.
Astronomy proceeds along two tracks: the theory track, and the data track. Physicists at chalkboards derive equations that predict what might be found or try to explain what is found (03/28/2010, 01/20/2010, 01/13/2010). Observational astronomers gather the raw data with telescopes. Sometimes these tracks intersect. Sometimes one precedes the other. One might expect that observation would lead theory, trying to make sense of new observations. Often, though, theory leads to discoveries. Theory can even determine what observations get made, and what an astronomer “sees” with the senses – as when today’s astronomers pursue their mad quest (08/03/2009) for dark matter (02/28/2008) and dark energy (07/17/2010, 10/08/2009). If the observations in the past 5 decades have been surprising, the theories have been even more so (06/30/2008): inflation (02/24/2009, 04/18/2008), black holes with universes inside them (04/10/2010), parallel universes, and the multiverse (02/22/2010, 12/05/2008). While one would hope observations would constrain theory (08/26/2009), some of the latest theoretical speculations seem like acts of desperation to maintain beliefs in spite of the observations (03/19/2010, 10/28/2009, 09/28/2009, 11/17/2008; cf. 10/29/2007).
We’re all together for the ride on our planetary spaceship. We have been given a phenomenal platform for scientific discovery (watch The Privileged Planet on YouTube). Fallible as we all are, it should not be surprising to be surprised by what we find, as we peer farther into the unknown with better instruments. What is surprising is for any of us to grant prophetic powers (both in terms of prediction and understanding) to a class of fellow mortals (06/23/2009, 10/16/2008), just because they label themselves scientists (03/10/2010, 01/15/2008). The spirits of the prophets are subject to the prophets. As new data comes rolling in from Kepler, MESSENGER, Herschel, Planck and future missions, let’s keep the marketplace open and a lively place for debate and critical thinking.