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Monday, 22 June 2015

Have we found the first stars in the universe?

I'll be up front: I had my stag weekend yesterday, and I'm in no fit state for a video. But there're some good space exploration stories anyway - the universe doesn't stop for my sore head!

First stars found?
According to the Big bang theory (and yes, it's still just a theory and always will be, that's science folks) shortly after the universe began it was a soup of hydrogen, helium, and some trace amounts of lithium. Every other chemical element - like, say, all the carbon and oxygen atoms that make up you and me - were cooked up in the cores of stars. That sounds weird, that you were cooked up in a star? Here's how...

Above: The 'can we hurry this along, my tea is burning in the oven' version of nucleosynthesis.  

Here's the long version if you like your nuclear physics*...

Above: The in-detail version of nucelosynthesis.

What this means is that the very earliest stars - generation number 1, also called population 3 for historical reasons - must have been very different beast than the stars we see today: Almost devoid of heavier elements, they would be detectable by spectroscopy today as the most powerful telescopes can see light that has been travelling since that early time. Using the Very Large Telescope of the European Southern Observatory an international collaboration between the Universities of Lisbon, Geneva, California, and Leiden has found what they think might be a clump of these very early stars, nestled in a galaxy in the very early universe (link in the subtitle above to the paper).

To be fair this isn't a confirmed find: They are looking at a galaxy over 13 billion light years away, and 13 billion years into the past, so this is on the limits of what can be done. And the evidence doesn't match up with Pop 3 stars perfectly - the team believes this very young galaxy has waves of star formation moving through it, with the pop 3 stars on the leading edge of the wave and consuming the 'cleanest' gas clouds.

But, if this pans out, our civilisation is now looking at the first lights the universe ever saw....

Venus is (almost certainly) a volcanic world 


Above: Artists impression of  balloon borne probe in Venus' atmosphere. Courtesy of me, and my ego.
Venus is an enigma of a world, and then some: It's chemically complex atmosphere is so dense near the surface that it acts more like an ocean of hot gas than air, and the weather patterns include gigantic double-eyed hurricanes and mysterious UV absorbing chemicals in the clouds. On top of these myteries, Venus' surface is bizarrely young, the whole planet rotates backwards and very slowly, it's mountains are covered in a strange layer of highly radar reflective material, and sometimes the chemical composition of the upper layers of the atmosphere will change abruptly for no obvious reason.
Yet there is a layer of Venus' atmosphere, 70 km above the scalding surface, that is the most Earth like environment we've ever discovered - Earth like pressure and tropical temperatures.

Exploring Venus is, and always has been, a major challenge: That ocean of super-heated gas that covers the surface cooks landers in hours. Balloon probes have floated through the atmosphere, before the winds drew them down to the crushing depths. But now, thanks to the (now destroyed) Venus Express mission by ESA, Venus has given up a crucial secret: It is a world with active lava flows.
Above: A Venusian mountain. Not pretty, but neither would you be under 90 atmospheres of red hot CO2. Courtesy of NASA.
The Venus Express team have found spots resembling lava flows on the surface, near the mountains Maat Mons and Ozza Mons. Now they have revealed that these spots are first getting much hotter and then cooling again over a matter of days.
This is a pretty strog indicator that the flows are still active in some way, and it begins to unravel some of Venus' mysteries: Active lava flows means active volcanoes - which mean that there are new chemicals being blown into the atmosphere by  volcanic plumes and could start to explain the odd chemical changes in Venus' atmosphere, and ongoing lava flows could also explain why the planets surface is so young - it is young (geologically). A geologically active Venus also makes a more tempting target for future space missions, so here's hoping this inspires a few balloon riding probes in the next few years....

The clearest views of Pluto yet:
The New Horizons probe has obtained its best views of Pluto (and it's largest moon, Charon) ever:

Above: Courtesy of Phil Stooke at unmannedspaceflight.com
Details are definitely starting to emerge, but so much of the most interesting stuff is still tantalisingly hidden just beneath the limits of resolution. If I could go up there and give New Horizons a push I would do (any supermen reading this please considr that a request)...

My unsubstantiated opinion: Will the rise of the nanosat spell doom for manned space exploration?

Above: A cube sat, sitting on someones desk. I don't know whose. That's at least a few tens of thousands of pounds of machine there. I hope they don't have a wobbly desk leg ....
I talk about cubesats as lot here: Cubesats are miniature spacecraft used for research- each basic cubesat is just 10 cm on a side, and weighs only 1.33 kg.... and they've been an amazing hit: This year has sen the launch of the first cubesat with a drive capable of propelling it to another planet (the Planetary societies Lightsail-1), it will also see the first ever interplanetary cubesats (which are hitching a lift to Mars on the back of the MAVEN mission there), and we may also see some of the first launching systems dedicated to cubesats and cubesat sized payloads begin operation. The field of developing cubesats into more than just high tech toys is booming, with novel ice powered engines, new kinds of thruster, and NASA initiatives. We might soon be seeing interplanetary missions for under $10 million thanks to cubesats.

We're also seeing efforts to push the envelope with miniaturisation even further - like the ongoing efforts to develop chipsats: Satellites that are effectively just a sliver of silicon wafer. These postage stamp craft have even been touted as a potential way to build an affordable interstellar probe, using Jupiter's magnetic field as a massive particle accelerator, and deploying a swarm of ultra high speed chipsats this way, in a fashion reminiscent of the 'starwisp' starship design. They've also been put forward as a way of exploring Jupiter's most habitable moon, Europa

Cubesats and other such miniature spacecraft have opened up space to a section of the world that wouldn't otherwise get the opportunity to do more than look to the sky and dream: Less wealthy nations, Small private concerns, colleges and universities have all had the high frontier opened up to them. So will space craft get smaller and smaller? And what will that do to our efforts at space exploration?

Above: A talk on the 'Micro and nano satellite revolution. I assume this means the revolutionary technologies, not a revolution that happens to use nano sats as weapons, dropping out of the sky onto peoples heads. Although I did reinforce my umbrella for a reason.... Courtesy of the National Physical Laboratory. 

In my (very humble) opinion the answer to the first question is both yes and no: We will  - we are already - seeing an increase in the number of nanosat missions. It makes sense, as they allow people with interesting ideas but limited budgets access to space, as well as giving people who want quick to develop and launch missions, like the military, a new avenue (it's no surprise therefore that DARPA are among those developing their own nanosat launcher).

I'm very, very, happy with all of this, but there is a potential downside: A new generation of ultra small unmanned craft means that the demand for the heavy lift rockets needed for manned exploration goes down. That means their price er launch goes up, which makes all manned space exploration more expensive. So will we see the slow death of manned exploration by economy , as the miniaturisation of unmanned space craft makes unmanned exploration much more efficient?

For my money no - there are still missions that will need a big mirrrors, big antenna, bulky power sources, and other things that cannot be miniaturised. Then there's the burgeoning space tourism industry to consider, and the demands it will make. What I expect-  and hope - to see is a diversification: More missions of the smallest sizes, but also at least as many missions of larger sizes. Then there's the economy of scales to consider: it is cheaper to launch many small missions on one bigger heavy lift rocket, than to assign each nanosat its own launch. I can understand the concern of manned spaceflight enthusiasts, but I don't believe the rise of the cubesat will kill off manned spaceflight - it will take another botched and unrealistic attempt to relive Apollo 'glory days' without assigning the needed budget, and the resulting public backlash against wasteful government spending, to do that.

If you're curious, here's the cubesat website,  and here's presentation on upcoming cube sat technologies

Above: Art work showing lightsail-1, the first ever cubesat with an independent space drive that could take it to another planet without assistance. Courtesy of the PlanetarySociety.

*All three of you.

Elsewhere on the Internet:
Chipsats are go!

Titan is dissolving!
Robots with tentacles 
Taking pictures of exoplanets

4 comments:

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