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Thursday, 7 December 2017

'Liquid' - in deep frozen interstellar ice.

The rings of Saturn, made of trillions of ciy particles loaded with organic matter - how far can chemical evolution get in such places? 

Life arose here on Earth... but how far did purely chemical evolution get towards life, on the planetoids and protoplanets of the early solar system? New research from Hokkaido University implies it might have been further than we thought. 

Meteorites dating from long before Earth have been found to contain the chemical components of proteins, cell walls, and even building blocks of DNA. Exactly how that happens is badly understood. We know these meteorites are fragments of ancient proto-worlds - worlds which were surprisingly planet like, with liquid water percolating through their rocks, planet like cores and volcanism, out gassing driving short lived atmospheres, and magnetic fields. They could have provided the right environments to process the more primitive chemistry in the Sun's protoplanetary disk.

But some meteorites contain relatively advanced pre-biotic chemistry despite showing no sign of ever having gotten above freezing. So where did it come from?

Now a surprising explanation has been discovered: Researchers from Hokkaido University in Japan have discovered that simple organic compounds, frozen in interstellar ice, start reacting with each other as if they are in a liquid, when exposed to ultraviolet light. The interstellar ice itself, despite being far below freezing, seems to behave like a super cold fluid - somehow. 

Above: Deep frozen, artificial, 'interstellar ice' bubbling like boiling water under UV light.

That's plenty of a mystery itself, but discovering that this kind of chemistry can take place in the ice grains floating in space (instead of a planetary environment) literally opens up a sky full of new possibilities: Across large parts of the universe worlds could be forming with half the chemical steps towards starting life already done.

Our skies might just have become a lot more crowded. For the original paper click here.

Thursday, 23 November 2017

Did Earth just get buzzed by an alien starship?

 
If it was one of these then we're all in trouble.


To answer the question in the title....No. 

Well. Almost certainly no.

But hang on, I should fill in the back-story here.... the object causing all this fuss is pretty odd. Called 'Oumuamua' it's (we think) an asteroid... although it's probably the weirdest, most scientifically compelling, asteroid we've ever found. 

Oumuamua was spotted in mid October of 2017. At first it was a fairly unremarkable spot of light: Probably some small, dim comet that no-one had ever picked up on before, was what most astronomers thought. 

Then they plotted its course backwards, to see where it had originated from: Oumuamua came from outside our solar system - from interstellar space. And, if it came from outside our solar system then it was, originally, a piece of another star system. No-one has ever seen such an object before - a natural interstellar traveller. Computer simulations have tentatively suggested that about one such object should pass through our solar system every year, but to actually spot one was like actually filming a Sasquatch - a mythic beast, captured on film.  

  
Above: The course Oumuamua took through our solar system, passing right by Earth.

The weirdness then got weirder, turning from " minor but historic discovery" to "whoa.. what?". Firstly this asteroid had, as you can see in the video above, swung relatively close by Earth. That's interesting, but maybe not very surprising - if it hadn't been in our neighbourhood we might well have never spotted it. 
But its shape is what has got everyone's heads a-scratching: Asteroids and comets range from potato to ball shaped. But Oumuamua is a stick shape: Ten times as long (about 800 meters long) as it is wide. 

Sasquatch has sprouted a third leg, and wings.*  



Above: The odd shape of Oumuamua. 

The colour of the asteroid (which can be broken down to reveal clues to it's surface composition) is reddish. that implies the surface is covered in the same kind of organic molecules - the same kind implicated in the origin of early life on Earth - that we see on the surface of comets. But, unlike a comet, this object has no trace of vapour coming from it, or of any ice. That suggests it's a rocky or metallic object beneath the organics... but how that squares with its strange shape, extreme origin point, is anyone's guess. 

So we get to the crux of the question: This looks like no natural object we've ever seen. So could it be an artificial one? it's extremely unlikely. At present there is no news of any heat signature, radio or microwave emissions, or other behaviour suggesting technology. Its speed, whilst very high (26 km/ sec) is still very slow for an interstellar probe - although that is assuming any probe building aliens would have similar life spans to ours (and there's no reason to assume that really, they could live much longer and be much more patient). 

But none of that is confirmation of a natural origin either - and while that's the most likely scenario by a long way, it must still be a spectacularly unusual natural origin to have produced such a strange object. That means it could a be a window into some truly alien geological processes, happening far, far across the universe from us.... Not aliens, but very, very alien natural processes. For that reason the astronomical community is gathering all the information it can on this object, before it disappears beyond the range of our telescopes. And, just in case, Centauri dreams website reports that SETI (Search for Extra Terrestrial Intelligence) and Breakthrough Listen organisations are/have been keeping Oumuamua under observation. 

As they say, watch this space.... 

UPDATE: To make things even more interesting a mission to hunt down and examine Oumuamua (or any other interstellar asteroids) is being proposed - some details here.

Sunday, 12 November 2017

The Universe in 101 words: Will we return to Saturn's moon Enceladus?

Above: Enceladus, an ocean world covered in ice.

Our solar system is awash* with ocean worlds. And thanks to the Cassini missionary we've gotten to know one, Enceladus a 500km wide moon of Saturn, really well.

So what's it ocean like?

Dark - the ocean's covered in 20km of ice - but maybe not totally black: There's volcanic activity on the ocean floor, possibly like the white smoker vents of Earth, so there'd be the dim carmine glow of volcanism. More importantly the salty, alkaline, water contains organic chemicals and hydrogen - food for possible micro-life.

Cassini's mission is over - but its now hard to imagine us not returning to Enceladus....

*Sorry.


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Above: The geysers of Enceladus, backlit: The ocean is literally leaking into space!

Sunday, 22 October 2017

Answers for students: What is a light year?

Above: A nebula. The smallest part of this picture you can see in this picture is thousands of times bigger than our whole world - so normal measurements of distance just don't work. Unless you're a linguistic masochist who likes having to saying "billion trillion trillion trillion quadrillion" after everything.

This one comes up a lot - It comes up in exam questions, and everyone seems to stumble over it: What are these 'light years' that keep being mentioned by astronomers and sci-fi shows? Do you have to eat less calories, or keep at least one house light on nonstop for 365 days to make them?

And the answer is: No. I eat however many calories I like (to be fair I'm starting to get a bit fat and have to go for runs) and I leave all the lights on in my house all the time anyway.

I'm not scared of the dark. I never admitted to that. Ahem

Anyway...

A light year is NOT a measure of time. Yes, I know it has the word 'year' in it's name. Yes, that's a pretty dumb and confusing thing to name a measure of distance. No, I can't do anything about it.

The important bit is that we understand the dumbness: It's called a 'light-year' because it is how far a beam of light will travel in one year (if it doesn't hit anything). So, to the astronomers that first came up with it, 'light-year' seemed to fit.

So, how far is it? Well we can convert light years to meters like this: 

A beam of light travels at 300,000,000 meters per second. To work out how many meters are in a light year, we just need to work out how many seconds are in a year and multiply that number by 300,000,000 meters.

Seconds in a minute = 60
Minutes in an hour = 60
Hours in a day = 24
Days in a year = 365.25*

So the number of seconds in a year is 60 x 60 x 24 x 365.25 = 31557600. 
And, for our grand finale, the number of meters in a light year is 31557600 x 300,000,000 = 9,467,280,000,000,000 meters.

Or, in other words, a very, very long way. It's the absurdly big size of the distances out in space that makes astronomers use light years as their units of distance.

Above: This is the Pleides star cluster, which is 43 light years across. Work that out in meters, using the method above - how many millions of millions of millions is it? And how much longer does it take you to say "Captain the engines cannae take it for another (insert millions of meters)" than "Captain the engines cannae take it for another 43 light years"?

Where things get  kind of crazy is when you think about what those huge distances mean for how we see the Universe: We see stars with light, which is the fastest thing we've ever discovered. The nearest star to Earth (after the Sun) is four light years away. That means it takes light from it four years to reach us - when you see it in the sky you are seeing it as it was four years back. Most stars are much further away, hundreds or thousands of light-years. Which means that, if you look up at the night sky, you are not seeing those stars as they are today but as they were hundreds or thousands of years ago. 

When you look at a star you are, very literally, looking hundreds or thousands of years into the past.


So... yes Doctor: Time travel is possible - in this limited way at least.

A really good example of this is the star Betelgeuse, in the constellation of Orion. Betelgeuse is unstable, and in danger of going supernova. But, because it is 650 light years away, it might already have exploded in a supernova. Right now it could well be a huge cloud of debris. If that had happened anytime over the last 650 years we wouldn't know about it yet, because the light that makes up the image of  the explosion wont have reached us yet. 

When you see Betelgeuse in the sky, you might actually be looking at its ghost.

So cut astronomers a bit of slack. Yes they're a bit odd and out of this world. But if your job started at that level of weird (and it gets a lot worse from there, with hairy black holes, lenses made of empty space, and invisible matter that passes through us all the time like ghosts) you'd be a bit odd to by the time you hit retirement.


* The 0.25 is because each orbit of Earth around the Sun doesn't quite match a whole number of days, leaving us with a quarter of a day over. For this reason every four years we have a leap year, with an extra day, to compensate and keep the calenders in line with what Earth is actually doing.

Saturday, 14 October 2017

Sound In Space: The Song of Jupiter

Above: The chaotic, Shoggoth inspired, swirl of massive storm systems at Jupiter's pole. Courtesy of NASA/JPL
The JUNO space probe has been wowing the Earth as it returns astounding images of the beautiful and titanic weather systems that shroud Jupiter - but there's another side to the exploration of the King of the Giant Planets: Jupiter's song. 

While space probes cannot pick up the actual sounds in Jupiter's clouds, (due to there being the vacuum of space between them and the planet), their radio antenna can pick up the natural radio transmissions from the giant world's immense magnetic field. 
So, for the full 'Jupiter experiance' try playing the two videos below - one a high def flyby of Jupier's cloud tops and one a recording of its eerie radio song - at the same time....





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Sunday, 1 October 2017

Five of the strangest asteroids and dwarf planets...

Above: Pluto, a world half the size of the US but stranger than anything dreamed up by sci-fi writers.

Most people thinking of space exploration think of the planets - Mars, Venus, even Jupiter and its Moons. But that's missing something - hundreds of somethings in fact: The large asteroids and dwarf planets make up a collection of worlds as varied and compelling as the terrestrial planets. So here are a few of the oddest...

Ceres:
The king of the asteroid belt, Ceres is a dwarf planet nearly a thousand kilometres across. It's also one of the relatively few asteroids to have been visited by a human space craft - in fact the Dawn space probe is still in orbit, surveying this small world. Despite its small size Dawn has shown that there's still recent signs of geologic activity on that 4 billion year old surface, and perhaps even hints of subsurface water.

Above: A simulated flight over Ceres, assembled from data supplied by the Dawn probe.


Vesta:
The first small world visited by the Dawn probe, Vesta proved to be a world with a history of cataclysmic violence. Already suspected to have been a hot, churning, volcanic world in its youth, Dawn found that the tiny world’s entire South Pole had been obliterated, not once but twice, by gigantic asteroid impacts. The largest of these was so huge it left the 'ripples' caused by the shockwave permanently imprinted in the Vestan rock.

 
Above: Dawn's greatest finds at Vesta

Psyche:
Although we've only ever seen this world at a distance, through telescopes, it is due to be visited by a unique space probe (also called 'Psyche') in 2026. Why? Because it's a solid chunk of metal the size of the state of Massachusetts. The only sensible explanation anyone has come up with (so far) is that Psyche was once the core of a planet - a planet that suffered some terrible fate which stripped down to its metal core...

 Above: The bizarre metal asteroid Psyche, and the mission to explore it.

Sedna:
It's unlikely that Sedna, a world 8 billion kilometres from Earth with a year over 11,000 Earth years long, will get a visit from any spacecraft soon. Even so, it's playing a pivotal role in our exploration of the dim outer reaches of our solar system. The dwarf planet's odd shaped orbit could be the result of the gravity of a ninth major planet, far out in space. Or, perhaps even more intriguingly, it could be a sign that Sedna is not really a member of our solar system at all: It could have been a loosely bound dwarf planet of another star, kidnapped by our sun during a rare stellar flyby.

Above: Think you know how far a long way is? Well take a look at the orbit of Sedna...

Pluto:
I take it you've heard of this one? Although the debate still rages in parts as to whether its demotion from planet to dwarf planet was a fair one, I really don't think this immense and incredibly complex ice world cares. From it's weird hundred meter blades of ice, to its nitrogen ice glacier ocean on which mountains float like ice bergs, to the hints that rivers of liquid nitrogen once flowed on its surface and might well still run beneath its subsurface, Pluto has every reason not to give a damn what we teeny humans classify it as. But, thanks to the New Horizons space probe, this beautifully weird world has, been opened up to human eyes...

 
Above: A virtual fly over of Pluto, assembled using data from the New Horizons mission.


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Wednesday, 12 July 2017

Sound in Space: The drumbeats of pulsars

The Allen Antenna array.

The stars are beautiful, or at least very sparkly. But most people will tell you they're not much to listen to - after all, in space no-one can here you scream, so how would you hear the stars? But there are signals out there - radio wavelength signals - that we can listen to with the right equipment.

So, if you wore radio dishes on your ears, what would you hear?*

Not a peaceful sky, or even a snatch of Beethoven. No, you'd hear a Milky Way echoing to the buzzing, humming, and drumming sounds of pulsars. These are incredibly dense objects, forged from the collapsing cores of supernova - and spun up to incredible speeds by them. Never more than twenty kilometres across, a new born pulsar can spin hundreds times a second. They give out intense beams of radiation, including radio waves, so as they spin radio antenna on Earth hear the click of the beam briefly sweeping over us.

There are old, slow ones that drum like a runners footsteps...


... and there are fast young ones that swarm in star clusters like 47 Tucanae, filling the sky with a whine like the universe's most terrifying cloud of mosquitoes...


But a universe full of strange knocking and humming sounds isn't the odd bit. The odd bit is that you can buy an album of music made using them.

*Given my knowledge of fashion this could actually be a thing for all I know



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