Tag Archives: Discovery

Water, water everywhere!

12 Mar

Over the past week or so we’ve seen a few stories regarding wet bodies in our solar system.

First, there was news about water on Mars. Now the news wasn’t so much that there was water on Mars, since that’s been pretty well understood for a while now (thanks in large part to the rovers Spirit, Opportunity, and Curiosity), rather how much water there was – and it’s plentiful to say the least.

Mars with a vast Northern Ocean (NASA/Goddard Space Flight Center)

Mars with a vast Northern Ocean (NASA/Goddard Space Flight Center)

Using land-based infrared telescopes (the ESO’s VLT and NASA’s Keck), NASA was able to measure the hydrogen isotopes in Mars’ atmosphere. The results indicate that Mars one had 20 million cubic kilometers of water – more water than is in the Arctic Ocean here on Earth today. Astronomers are also currently suggesting that the Martian water was contained, mainly, in one large ocean surrounding the Red Planet’s north pole. It would have covered proportionally more of the planet’s surface than the Atlantic Ocean does here.

Nowadays on Mars it’s bone-dry, quite a bit different from ~4 billion years ago. Current estimates suggest that Mars’ ancient ocean contained about 6.5 times more water than what is currently observed in Mars’ polar ice caps, meaning that a great deal was likely lost into space as the Martian atmosphere thinned 2-4 billion years ago (though some water could still possibly be trapped in a permafrost layer).

The next news item this week is regarding Enceladus, an icy moon of Saturn. Now again, we’ve understood for a while that this moon had a sub-surface ocean of liquid water, trapped beneath an icy crust, but the news this week is tantalizing: the possibility of active hydrothermal vents in the moon’s southern ocean.

Hydrothermal activity on Enceladus (NASA/JPL-Caltech)

Hydrothermal activity on Enceladus (NASA/JPL-Caltech)

Announced just a couple days ago thanks to data from the Cassini spacecraft, astrophysicists have been able to pinpoint the origin of tiny particles of silica that the spacecraft had been detecting in space as it orbits in the area. And the origin appears to be the southern ocean of Enceladus, a 10km deep body of water. How the silica particles form is a chemical process that takes places when ocean water interacts with volcanic activity on the ocean floor.

Precisely the same process has been observed in only one other place so far: right here on Earth. And on our world, hydrothermal vents are teeming with life.

Jump ahead to today, and NASA announces, using Hubble data, that the largest moon in our solar system has a sub-surface ocean of liquid water of its own.

Ganymede, a moon of Jupiter, has been theorized to have a sub-surface ocean since the Galileo probe visited the area in 2002. Shifting magnetic fields were a major clue indicating the presence of water, though the data at the time was inconclusive. But now a novel idea has allowed a team of astronomers to make use of the Hubble Space Telescope to study Ganymede’s shifting magnetic fields from afar: patterns in the moon’s auroras.

An illustration of Ganymede's auroras (NASA/ESA)

An illustration of Ganymede’s auroras (NASA/ESA)

By understanding how different materials impact magnetic fields, and how auroras present themselves through those magnetic fields, the astronomers were able to understand Ganymede’s make-up by studying the auroras using Hubble. What they found is an ocean of water. (Edit: not only an ocean of water, but a large ocean. Ganymede could have more water in its salty subsurface ocean than Earth does in all our oceans combined.)

With all this in mind – and not to mention other wet worlds, like Europa – the solar system is starting to look a little more damp than it was once thought to be. And here on Earth at least, it is well understood that anywhere you can find water – in any form – you are virtually guaranteed to find life as well.

So how do these discoveries impact the prospects for finding life in our solar system beyond Earth?

On Mars, I’m not sure it changes much. It’s been understood that the planet was once wet, that it was wet for hundreds of millions of years (if not a billion or more), and that the environment was once life-friendly. This week’s discovery drives home the idea that there was plenty of water, but I don’t know that it’s a game-changer.

For Enceladus, this is a significant discovery. Adding in the fact that geysers have been previously detected with organic chemicals, this icy world now has to be considered one of (if not the most) likely places to harbour life in our solar system. As we understand life, it needs water and an energy source; Enceladus now seems to have both. Contemplating what might be swimming around in that alien ocean right now is an intriguing thought. (Maybe Enceladus leap-frogs Europa as the target for a robotic submarine mission?)

Ganymede? Add it to the list of worlds with liquid water that require more study. (I would similarly categorize Europa.) Questions abound as to the nature of their oceans, if there is any volcanic activity, do they cover the entire world, and could there be life?

Clearly we have some exploring to do.

Astronauts on board the International Space Station capture an image of the Space Shuttle Endeavour prior to docking during the mission STS-130 in February 2010 (NASA).

Astronauts on board the International Space Station capture an image of the Space Shuttle Endeavour prior to docking during the mission STS-130 in February 2010 (NASA).

Robin Williams amazing space shuttle wake-up call from 1988

12 Aug

Reprising his role from “Good Morning Vietnam”, Robin Williams made the inaugural wake-up call to the Space Shuttle Discovery in 1988 during the mission STS-26.

Williams’ wake-up call was the first of the mission, and the flight was the first space shuttle flight since Challenger exploded during launch in 1986.

In the video of the wake-up call from NASA, flight controllers can be seen laughing along with the recording from Williams.

“Gooooood morning Discovery! Rise and shine, boys. Time to start doing that shuttle shuffle. You know what I mean. Hey, here’s a little song coming from the billions of us to the five of you,” Williams is heard saying.

Williams died on August 11 after an apparent suicide.

He was 63.


As we sail into the unknown

13 Sep

This is a big moment in human history, though like many moments it probably won’t sink in for years to come. Nevertheless, humanity – with the reach of the incredibly long-lived Voyager 1 space probe – is now a civilization of the stars.

The official announcement came from NASA yesterday (September 12, 2013) after careful data analysis from Voyager 1’s Plasma Wave instrument: the spacecraft has passed though the heliopause (the bubble that separates the inside of our solar system from the outside) into the interstellar medium.

To watch the full press conference, hit play here:

NASA scientists were able to confirm Voyager 1’s exit from the heliopause by measuring a significant change in the plasma density that surrounds the probe. And interestingly, the change they noted was a marked increase in density. This may seem counter-intuitive, but as the plasma temperature of the interstellar medium is significantly cooler than the solar system’s plasma, the increased density makes sense – and was in fact expected.

(Warning, the following is a simplification: All things being equal, cool objects have a higher density than warm objects, as their molecules have less energy and pack closer together. This is why solids are denser that liquids; liquids denser than gases; gases denser than plasma – in each state of matter transition energy is added, which causes a decrease in density.)

“Exploration is in our nature. We began as wanderers, and we are wanderers still. We have lingered long enough on the shores of the cosmic ocean. We are ready at last to set sail for the stars.” ― Carl Sagan

The other interesting thing to note is that Voyager 1 , it appears, actually entered interstellar space on August 25, 2012 – more than a year ago! But it took until now to make sense of the data the probe was sending back. But I kind of like this. When we as a species are going somewhere and doing something no one has ever done before, it takes time for us to understand what we’re seeing and what’s happening. Exploration and discovery doesn’t happen in 20 seconds – it takes years (and historically speaking, many years) of concerted human effort to accomplish these amazing firsts – whether we’re talking about crossing the oceans, inventing medicines, sailing around the globe, building landmarks, landing on the moon, and now leaving the solar system.*

Voyager 1 is right now about 19 billion kilometers from the Earth, or 125 times further from the Sun than we are, and getting ever further away at a speed of about 60,000 kilometers per hour – or roughly 500 million km per year! A little perspective: we think of the dwarf planet Pluto as “far away” but Voyager 1 passed the orbit of Pluto in 1989 – 24 years ago!

And let’s not forget about Voyager 2 either. It is still within the heliopause, and will also cross into interstellar space in the coming years. Voyager 2 is on a different – slower – trajectory than Voyager 1 and so it is about 5 billion kilometers behind its twin sister, on a southbound course away from the Sun.

The Voyager mission will, I expect, to continue to deliver more discoveries. As the probe continues to sail into the unknown I look forward to it sending back new data that will continue to answer questions – and perhaps more importantly – raise new questions, in order to push our understanding of the universe forwards.

To read more about the Voyager mission, check out these other posts I’ve written on the subject over the last couple years.

* While Voyager 1 is now travelling through interstellar space, it technically hasn’t left the solar system. I know this might sound bizarre, but it’s due to the fact that the Sun’s gravitational influence reaches far beyond the influence of its plasma. There are (at minimum) billions of chunks of rock and ice in the Oort Cloud that orbit our Sun over thousands of years that are still many times further away from the Sun than Voyager 1 is. It may be in fact thousands of years before Voyager 1 passes the last of the Oort Cloud objects. All that having been said, the heliopause is accepted as the limit between inside our solar system and “amongst the stars” in interstellar space, just as Oort Cloud objects are “among the stars” even while being bound by gravity to our Sun. Phil Plait also wrote on this subject here.