Friday, December 20, 2013

Astronomical Predictions for the New year

Since the start of a new year often brings prophecies of the upcoming trip around the sun, here are some space-related predictions. These won’t necessarily come true in 2014, but I am confident all will occur eventually, most, I believe, in the lifetimes of the readers of this article.

Mars once had abundant liquid water on its surface. We have lots of intriguing, if inconclusive, evidence of liquid water still appearing seasonally in places on Mars where one might reasonably expect it to be. Photos of the same region, taken over time, show dark streaks running down the sides of cliffs and crater walls. It looks for all the world like liquid water running down slope. These have been explained as CO2, which is heavy and rolls down hills. Frozen subsurface dry ice sublimates to gaseous CO2 and carries darker material from just below the surface with it, creating the stains.

  Streaks seen in Newton Crater could be due to liquid water (Image: NASA/JPL/University of Arizona)

I predict that NASA or another space agency from Europe, India, China or wherever, will sometime soon send a probe to one of these locations and verify that is liquid, albeit very salty, water.

Mars isn’t the only non-terrestrial location with liquid water. Jupiter’s moon Europa has a surface layer of ice, perhaps 10 miles thick. Below that is a liquid ocean, 60 to 100 miles thick, if the spotty gravity/density data we have from Europa is correct. And just to bolster that nearly universally-accepted assumption, in mid-December of 2013, the Hubble Telescope captured what are almost certainly erupting geysers on Europa. Europa’s subsurface ocean is kept liquid by tidal stresses on the moon from Jupiter and Ganymede, the next Jovian moon beyond Europa, and the largest moon in our solar system. They constantly squeeze and pull on Europa’s crust, which generates tectonic activity that heats the ocean, keeping it liquid.

This is an artist's concept of a plume of water vapor thought to be ejected off the frigid, icy surface of the Jovian moon Europa, located about 500 million miles (800 million kilometers) from the sun.
Image Credit: NASA/ESA/K. Retherford/SWRI

Not long after the Casini probe arrived at Saturn, it discovered mineral-laden water ice geysers blasting off the tiny moon Enceledus. It’s not clear if tidal stress comes into play here, as on Europa; it may be that subsurface the liquid water on Enceledus is transitory, and the geysers may stop any time.

Enceladus Ice Geysers. Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

What makes all three cases for liquid water interesting and prediction-worthy, is this: On Earth, almost without exception, where there’s water, there’s life. Even in cracks in rock a few miles below the surface of Earth, microbes can live in tiny water pockets.

I predict that we will find non-terrestrial life elsewhere on our solar system, probably in one of these three places.

Actually, I should write that as “non-terrestrial.” The quotations marks are there because Martian, Europan or even Eceledun life may well be related to Earth life. Planets and moons in our solar system are somewhat promiscuous; they are constantly swapping spit, as asteroids slam into these bodies and knock hunks of them into space. Any hitchhiking microbes may actually survive this unintended space flight, to populate any other world with supportive conditions, meaning liquid water, it might later land on. Whichever of these four bodies – Earth, Mars, Europa, or Enceledus – first developed life very likely spread it like a cosmic cold to the other three. And if that is true, that all life in our solar system is related, any microbes from another location in our solar system could cause deadly epidemics on Earth.

Several state of the art telescopes are now under construction, seeking funding or in the design stages. Some, like the James Webb Space telescope, Hubble’s successor, will be in space. Some, like Large Synoptic Survey Telescope, Giant Magellan Telescope, Thirty Meter Telescope, and the European Extremely Large Telescope, will be ground based, but dwarf in size and resolving power anything that exists today.


 Hubble’s successor, the James Webb Space Telescope, Credit

The Thirty Meter Telescope from above, Courtesy TMT Observatory Corporation.

Some, like the eLISA (Evolved Laser Interferometer Space Antenna) will search for gravity waves instead of light waves. Gravity waves represent the only direct source of information from the Big Bang itself. All forms of electromagnetic radiation were blocked during the first roughly 400,000 years after the Big Bang.

LISA Gravity Wave Te3lescope, Credit ESA.

Several neutrino telescopes now routinely survey space, and more sophisticated ones being designed promise to provide greater sensitivity and spatial resolution. Neutrinos represent the only direct evidence from the core of stars, where all the exciting stuff occurs.

I predict that over the next several decades, one or all of these telescopes will discover something that will turn astronomy and physics on their collective ears.

If I knew what that discovery was to be, I’d be writing my Noble Prize acceptance speech.

Several tens of thousands of objects baseball-sized and larger orbit Earth, the missions, but also the detritus of the dozens of space launches we humans do every year. The largest object currently in orbit, the international Space Station, dwarfs a football field in size.

Every one of them will eventually fall back to Earth.

Only one person, a woman in Tulsa, OK, is known to have been hit by returning space debris. She was jogging one morning when she felt a hard tap on her shoulder. She looked and found…something. It turned out to be a hunk of insulation from the second stage of a Russian rocket that launched a satellite a couple of weeks earlier. She was unnerved, but otherwise unhurt.

Stuff in orbit falls back to Earth all the time. Much of it burns up from friction with our atmosphere due to reentering at 17,000 miles per hour. But large, metallic hunks of satellites routinely survive this reentry and crash down. Two-thirds of our planet is water, so most of the stuff lands in the ocean. A significant fraction of the remaining land surface consists of rain forests, deserts and other uninhabited areas. So far, we humans have been lucky from this rain of space debris. That won’t always be the case.

I predict that some time in the near future, and major hunk of space debris will hit a populated area, causing destruction and injuring or killing humans on the ground.

My crystal ball reveals other space-related predictions, but the most significant of those involve timescales far beyond our individual lifetimes. And most are a lot scarier than any I listed above.