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Hubble, a window in to the past

8/25/2018

(Hubble image found here)

There is a way of actually looking in to the past. We do it every time we look up at the sky at night. The star light that you see now was released from stars many years ago. If you look up at the Sun (highly un-recommended) you are viewing the light that it released 8 minutes ago (i.e. it is 8 "light minutes" away from us). If you look at Alpha Centuri (highly recommended), our next nearest star (actually a ~ binary star system), you are seeing the light that it released ~ 4 years ago (i.e. it is 4 light years away).

This very cool, and somewhat disconcerting. Where the heck are we in time?! There are some stars (like Betelgeuse, a super red giant in the Orion constellation) that are at the end of their stellar life cycle (don't worry... still another ~100,000 years). Betelgeuse is ~ 700 light years away and is in it's last stage in 'life'. Therefore, even if it exploded 600 years ago we wouldn't know it for another 100 years; it takes time for that light to reach us. Being relatively near, a Betelgeuse supernova, would shine as bright as a quarter Moon and would rise to peak brightness over a couple of weeks and then fade...

So the question/s is/are: how far back can we see? I see the Sun now as it was 8 minutes ago, Alpha Centuri as it was 4 years ago and Betelgeuse as it was 700 years ago. If we take very powerful telescopes, can we see the light from ancient galaxies? The early forming of galaxies? Or the beginning of the universe itself...

Now suppose you hold up a window at arm's length the size of a grain of sand. Suppose that window is a powerful telescope. One of those powerful telescopes is the Hubble telescope and it's observations are staggering. Using high magnification and a long exposure the Hubble telescope spends a couple of weeks gathering light from a minuscule portion of the sky. The images captured peer across time at some 15,000 galaxies. The red-shift (resulting from the expanding universe) of some of those galaxies are such that the light from them was formed ~ 13 billion years ago. That is a mere 500 - 700 million years after the start of our universe! Answer to our initial question: We can see galaxies now that are literally 13 billion years old! And that's not akin to 'a human memory' (an interpretive mapping of our current being to a past experience), what you see in that Hubble image above, is (for all intents and purposes) an image of the past.

So although there are ~100,000 stars in our galaxy, the Hubble image shown above looks past the stars in our galaxy only showing (at my counting... correct me if I'm wrong!) about 10 individual stars, the rest of those different coloured dots (15,000 or so) are galaxies. WOW.

But there is an elephant in the room. How are there 15,000 galaxies in the Hubble image of a region of the sky that is the size of an image through a grain of sand at arms length?! Conclusion: There are a vast number of galaxies in our observable universe estimated at 200 billion to 2 trillion galaxies.

This should lead us to wonder, speculate, ponder, fascinate at, revere, be astonish at, be curious at, amazed, dumbfounded, flabbergasted, impressed and truly humbled by it all.

The ability to peer in to the past, is an important tool in understanding the early universe and how it evolved. It is images like this that show a snapshot of galaxies through a continuum of time that are stretching the boundaries of frontiers in cosmology.

The universe. Our living quarters. Home. In a cosmic sea, living on our pale blue dot.

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The image above was released by NASA on 16.08.18 as part of the Hubble Ultra Deep Field project.
Another important early universe/Big Bang observation is the cosmic microwave background radiation, which detects the microwave remnants of energy released from the big bang. Stayed tuned, for another post on this soon (hopefully!).

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Pin a Spider Down, Harvest it's Silk... Not any more!

8/22/2018

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Spider's silk is one of the toughest and strongest materials around, outperforming many synthetic polymers and metal alloys in standard mechanical properties. Aside from being very strong, they are lightweight and very thin (!), typically a fraction of the width of a human hair. So whats the problem in using spiders' silk in high-durability medical bandaging, waterproof textiles and flexible mats for intergalactic space travel?!? Well... you try pinning down a spider and harvesting its silk. Actually, dont try that, its been done, by numerous groups! Silk is perhaps best known to be made by spiders, but, in fact, is also produced by bees, wasps, ants, silverfish (not actually a fish!), mayflies, thrips, leafhoppers, beetles, lacewings, fleas, flies, midges and others (from wikipedia).

An ultimate goal in the biomimetic community (the science that tries to mimic nature to solve human problems), is to synthetically make spiders silk, without the spiders. So what's stopping scientists doing this? Farming spiders to make silk is an arduous process. Best case scenario you could get ~ 100 ft of spiders silk in one session, but then the spider would need time to feed and regenerate it's silk reserves. Options? Genetically make a monstrous spider to harvest huge amounts of silk or breed billions of spiders to do the job, or...

Spiders' silk, like many biological materials, are composed of a hierarchical structure. In a simple sense, spiders' silk is a spun protein fibre. It has long been known that the size of the protein units within the silk correlates with the strength of the silk; larger proteins generally means stronger silk. However, natural silks have a limit in the size of the proteins that they use; for whatever evolutionary reason this has happened...

For human purposes, it was proposed to mutate the spiders' DNA, insert it in to bacteria (poor things) and force those bacteria to make the desired proteins (this actually happens routinely in a biological lab). However, bacteria (I don't blame them!) cannot make such large proteins; it's been a running problem in biochemistry for some time. What the scientists did, therefore, was insert a DNA segment that would chemically fuse two smaller silk proteins to form a single large protein unit. To their joy and adulation, they succeeded. With protein in hand (or actually 'in dish') they spun these synthetic proteins in to a silk and found that they performed as well as natural silk, in terms of tensile strength, toughness, elastic modulus and extensibility!

Being able to make silk without a spider is a really promising prospect. Now that scientists can modify the protein size (and composition) within the fibre and use bacteria to produce the desired silk it leads to a whole host of possibilities in making future materials with enhanced properties.

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The image above was taken from a Business Insider video over here.
An interview of those scientists can be found on Science Daily.

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Showering with Meteors

8/20/2018

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Last week I climbed atop a hill in a secluded country park and gazed skyward. The seemingly ever-static black canvas was anything but. To the untrained eye mere dots of white peppered the sky and that's that; a friend pointed out a plane (well done). To those with an astronomical bent: bright red Mars, Venus and Jupiter all came to say hello. Binoculars and telescopes pulled galaxies, stellar clusters, nebulae and an assortment of stars ever closer.

The prized guest, however, lay in the dead trails of an ancient icy beast. The Swift-Tuttle comet was 'discovered' in 1862 but possible reports of this comet come as early as 69 BC. With an orbital period of ~133 years this 26km diameter comet sheds it's icy shell when in close proximity to the sun; warming, melting and flaking. Comets' origins are not fully known although using the velocity, mass and trajectory of many known comets it has been shown that they emanate from two icy regions outside of our solar system known as the Kuipier belt (for short period comets) and the Oort cloud (long period comets). Projects are still underway to determine the nature of those regions, their structure and how they got there in the first place. (As a point of reference, Pluto (~1,200km diameter) was reclassified as a dwarf planet, and is the largest member of the Kuipier belt family).

And so, every 133 years Swift-Tuttle leaves a trail of dust and ice in it's wake and summarily returns to it's lair in the deep (probably the Kuipier belt), gathering strength (basically ice and dust again...) and will visit us again in the year 2126.

As chance would dictate, our precious Earth, every year, passes through that trail of ice and dust. The Earth is already travelling at 30km/s around the Sun! So when comet debris enters the Earths atmosphere it heats up and we observe that as a bright arrow across the sky.

It's really quite beautiful. And rather personal. The light from a meteor is only momentary, normally less than one second. You cannot predict where exactly it will emanate from, and, if in a small crowd, you could be the only person who sees it, to the annoyance of everyone else! After about 1hour and ~30 meteors later (...and a nice hot cup of tea), we headed home to sleep.

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The image is accredited to Fritz Helmut Hemmerich and featured on Astronomy Picture of the Day 12.08.18. It shows an unbelievable long exposure shot of the Andromeda galaxy (our closest spiral galaxy) and captures a Perseids meteor shooting directly across it, marvelous.

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The Sun is HOT and we're going there!!!

8/16/2018

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NASA this week launched the first ever human probe (Parker Solar Probe) who's final destination is our beautiful star "The Sun". It will reach speeds of 430,000mph, faster than any human object in history. It will do this with a gravitational assist, as it fly's past Venus on its way to the Sun and is 'sling-shot' using Venus's gravity to accelerate it. At it's closest, the Parker Solar Probe will reach a distance of 3.8 million miles from the Sun which is less than 5% of the distance of the Earth to the Sun.

The mission? To study the Sun's complicated dynamic interior and to better understand how these processes affect the Sun's ejected material (an important concern for Earthlings). The Sun's 'corona' is a glow of plasma surrounding the sun extending hundreds of thousands of miles outwards (see image); it can also reach millions of degrees (even hotter than the surface of the Sun!).

Solar flares spew out huge amounts of materials that can be many thousands of times greater in size than our own Earth. The frequency of solar flares vary along a 11 year cycle, peaking somewhere in the middle. Scientists know that the frequency of solar flares is related to the changing magnetic fields within the Sun. Dark 'sunspots' form as a direct result of these fields and typically last from a few days to months; they also accompany certain types of solar flares.

So many questions to answer... This NASA probe should shed light (or be shed light upon... or melted) on some of the unanswered questions relating to the dynamics of the Sun; our planet's most important source of energy. The energy arriving from the Sun in one hour is enough to power the whole economy for a year...! But lets not get carried away, that is a more completed fete than one would imagine.

By the way... its quite amazing that its taken so long to do this. We've directly photographed most planets up close (including that pesky 'non' planet Pluto), landed on comets and other planets' moons, landed on Mars and even sent probes outside of our solar system; yet this visit to our highly visible neighbour is quite unique.

To put this in perspective: In Carl Sagan's 1980 book "Cosmos", in the closing chapter he lists a whole bunch of future space projects that WILL HAPPEN. Looking at it now some say that he 'prophetically' lists all of those things that have indeed happened, and mostly in the order in which they did happen: landing on Titan, landing rovers on Mars, landing on comets, etc. Lets be realistic, space missions take years-to-decades to plan. Thinking of those future programs will take all the bright minds of now to make their wildest dreams come true in the future.

Its up to our highly skilled youth to make those dreams happen.

Image courtesy of wikipedia here.

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Age Old Moon Crater Question... Resolved?

8/8/2018

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The Moon's surface is better mapped than the bottom of our Earth's oceans. Although that may seem surprising, it makes sense. The Moon has no atmosphere, meaning that light dispersion doesn't blur or impede our view of it's surface. Even viewing the Moon through our own atmosphere at night can yield high resolution images.

In fact, you can use a x10 magnification binoculars and a smart phone (resting the two with a very steady hand!) and take a surprisingly good photo. With enough stacked images and some image processing a high resolution photo of the Moon can be captured with relative easy... our side of the Moon, that is.

So (!), despite the Moon's surface being well accounted for, the mechanism of formation of streak-like 'rays' emanating from craters was not fully understood. UNTIL NOW. This research article must surely give hope to any budding scientist who thought 'table-top' science was only a thing of the past. In the paper scientists drop marbles on to a bed of flour, mimicking the behaviour of an asteroid impacting the Moon. Awesome.

What they observed was that marbles falling on flour that had been flattened shows a uniform circular spread of 'dust' forming around the impact sight. HOWEVER, when the marble impacts an uneven bed of flour (e.g. a bumpy grid of hexagons), rays or streaks emanate away from the impact sight. They explain that a bumpy surface concentrates shock waves along specific paths that breaks the normal symmetry of impact on a flat surface. This channels the ejected material along specific paths.

What is fascinating is that they found that the relative size of the marble to the spacing of the bumps in the flour actually determines the number of rays that emanate from an impact site. This is very useful! It means that astronomers can look at the craters on the moon, count the impact rays and then estimate the topography of the moon and/or the size of the asteroid that must have hit it. Given that the Moon has hundreds of thousands of craters, with some big-data analysis, scientists will be able to find out the size distribution of asteroid impacts for the past (however many) millions of years!

For some perspective... Check out this video that shows how some research initiatives constantly monitor the Moon for new impact sites. This can number hundreds of new craters every year.

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Water Discovered!... on Earth?!

8/5/2018

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The story of the origin of water on Earth is unresolved.

An interesting twist is that we now know that there is water trapped deep under the Earth's crust in the mantle and 'transition zone' (~500km under the surface) mainly in the form of crystals called ringwoodites (see image opposite, courtesy of University of Alberta) and wadsleytes. They are, of course, rather hot, and water doesn't exist in liquid form 500km under the surface.

However, when these crystals are spewed out to the surface of the earth from volcanoes, scientists can measure their composition using x-ray spectrometry. These crystals contain hydroxide ions (hydrogen and oxygen bound together), or crystal defects that have the potential to liberate a huge amount of water under the right conditions, such as reactions with hydrogen or melting.

How did it get there? Where did it come from? Is Earth unique? What can geophysical measuring techniques teach us about the finer structure of the Earth's interior? Can this water be mined and its contents released, or harvested? Will spaghetti really always break in to three pieces?... Ok that last question was not relevant.

The estimated water content in the 'transition zone' is up to a few times the water content of the oceans... thats a rather large amount!

Two prevalent theories of how water got embedded so deep is: 1) Water that was around during the formation of Earth clung on to dust and coalesced, and made its way in to a self-ordered layered formation (much like liquids of different densities separating), 2) layer formation from regular asteroid impacts containing water...

This doesn't tell us much though. Because if I were to ask you 'how did it get there', you could probably come up with those two options. The difficulty is measuring in situ (i.e. in an actual place where the things happen) and making physical models to describe a whole host of complex interactions including heat gradients, different materials, liquid motion of mantle, dynamic crystallization on large scale, time, gravity, seismic activity, etc. That is no simple matter.

At present, experiments using seismic waves are underway to get a higher resolution picture of what is going on beneath the surface and analyses of crystals spewed out from the 'underworld' also provides insights into the origins of water deep inside the Earth.

Either way, it is fascinating that water, or at least the materials for its liquid form, exists in what was thought to be a most unlikely place.

https://www.quantamagazine.org/the-hunt-for-earths-deep-hi…/

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Hubble, a window in to the past

Pin a Spider Down, Harvest it's Silk... Not any more!

Showering with Meteors

The Sun is HOT and we're going there!!!

Age Old Moon Crater Question... Resolved?

Water Discovered!... on Earth?!

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