Friday, 2 September 2016

'We Are Made of Starstuff': Planet-Gazing is Part of Who We Are (Featuring Planets Mars and Saturn)

What strikes me most when I look through the telescope is that I'm looking at objects that are so far away that their light has taken years to reach our planet. It takes light 4 years to reach the Earth from Sirius, a nearby star, while light from the Eagle Nebula takes 7,000 years to reach the Earth. For all I know, what I'm looking at may no longer exist in the form I can see, or may not exist at all. When we look up we are looking into the past.

So last week I traipsed out to the countryside after dark with my telescope to see the rare Venus-Jupiter alignment that may have been the origin of the Star of Bethlehem, and which won't occur again until 2065. Unfortunately I was thwarted by a combination of light pollution and sparse cloud cover low in the sky which meant that seeing just above the horizon was impossible. But as the sky darkened, three very bright objects appeared low in the western sky, and they were so bright that they were clearly visible to the naked eye even through sparse cloud cover, which had cleared by the time I found a spot to set the telescope up in.

The first bright object I set the telescope on was in fact the planet Mars, which is a minimum of 54.6 million kilometers from the Earth, It looked like it was emitting an eerie orange glow, and had grey patches decorating its face. It wasn't the red hue I expected based on what I know of Mars, as it looked a lot like this:


Image source
With craters, dark regions, polar ice caps and clouds, Mars is an incredible sight. The red rust colour comes from the very fine dust that contains iron oxides.

I should have spent longer gazing at Mars but I was excited by the excellent visibility and jumped straight to Saturn, from which there was no going back. The distance to Saturn from the Earth is constantly changing as both planets travel through space, but at their closest points they are approximately 1.2 billion kilometers apart. Saturn is the sixth planet from the sun and the second largest planet in the solar system. Galileo Galilei saw Saturn's rings in 1610, but it wasn't until a few decades later that astronomer Christiaan Huygens proposed that Saturn had a thin, flat ring. In fact, Saturn has many rings made of billions of particles of ice and rock, some as small as a grain of sand and others as large as a building. The rings are believed to be debris left over from asteroids, comets, and/or shattered moons.

Even a very blurry view of Saturn is easy to identify because of its trademark rings, but I had to use two special lenses to see them in detail, which was a lot of work because as soon as the lenses were fitted to the telescope the planet had moved out of sight, creating a steady dance between ringed planet and determined astronomer. It was worth it though:



I gazed at Saturn for so long that a farmer turned up with his son to see what I was up to.. Apparently someone had reported strange goings-on near his farm! He was baffled to find that I was looking through what was clearly a large telescope on a tripod, and although I acted fast to show him Saturn it was already out of sight by the time he'd walked over, and it would have taken some time to remove the lenses get it in range of the telescope again. In any case, the farmer was delighted with my excitement about the night sky, and left with a cheerful insistence that I return to this spot again to stargaze as often as I like. Something he said has stayed in my thoughts since then, though - he told me: 'I must admit, I come out here to check the sheep at night sometimes, but I never look up' (gesturing to the sky).

When I get a clear view of the night sky, my neck ends up hurting from craning it up for so long. It's always worth it. In fact, I've often wondered whether part of the reason we went from using four limbs to travel to two might be because we were so intent on looking up. Certainly our ancestors, who lived outdoors and didn't have the present visibility barrier of light pollution, spent much time gazing at, mapping, and pondering the night sky. They knew that some objects were stars and others were not because of the constellations they devised - they could see that the planets has varied paths across the sky. They knew this without aid of telescopes, just through continuous observation with the naked eye.

We may have forgotten this, but it's where our days get their name from:

Sunday is named after the Sun,
Monday is named after the moon,
Tuesday is the god Týr's day (known as Tīw in Old English),
Wednesday is the god Odin's day (known in Old English as Wōden - so, Wōden's day),
Thursday is the god Thor's day,
Friday is the goddess Freyja's day,
and Saturday is the god Saturn's day.

The planets, stars and constellations once played a significant role in our lives. For most of our history we looked up to the stars to gaze at the distant past, and even to try to see the future. I see the telescope I have access to as an immense privilege, and I actually believe that being able to see planets should be a human right. We are part of the cosmos. If we stop looking up, we stop seeing who we are and our small role in this immense universe. We also forget how incredibly fortunate we are to be here; how lucky, how random, how insignificant and special it all is at the same time. As Carl Sagan said, 'we are made of starstuff'.

I believe that everyone should be able to see what I see, and that's mostly why I write these blog posts. The universe is as much as part of who we are as this blue planet is. To view it and ask questions about it is not just for those of us with telescopes: much is visible with ordinary binoculars, if you know where to look. (For tips on how to start, see my short post on stargazing). There is always much to be gained from looking up.

To catch Mars and Saturn right now, follow the basic rules and look for the following rough alignment. It changes shape over time of course, which is why a night sky guide is so useful.

From Collins 2016 Guide to the Night Sky
As these amateur pictures show, Saturn, Mars and Antares will be visible through September and into October. Take a compass and look south west. They will be very bright, likely the brightest objects in the sky, bar a few random stars. On a clear night and with a keen eye you should be able to tell that they are not like the stars around them. Look for the triangular-shaped alignment, which changes over time but is still noticeably triangular. Good luck!

I'm going to head out soon for more Saturn-gazing, and to get a better look at Mars with the lenses, and to take a look at Antares, a supergiant star and the fifteenth brightest star in the sky that is often referred to as 'the heart of the scorpion' because it's found in the constellation Scorpius.

As for how far into the distance I've ever seen, remember when I spotted The Ring Nebula? It's 2,300 light years away. That will never fail to amaze me.

How far into the past have you seen?

Tuesday, 30 August 2016

Grow Your Own! Caterpillar to Chrysalis to Butterfly, in pictures

Want to grow your own butterflies? We just released five beautiful painted ladies into the world, and will definitely do this project again next summer!


Painted lady butterflies are a very common non-native species, but they're impressive all the same. Not only do they travel to Europe from Morocco in north Africa, through Spain, and then migrate to Britain in their thousands (sometimes in their millions), but entomologists have no idea why they travel such an immense distance, as each generation only carries out part of the journey before reproducing and dying. From Britain the painted ladies continue their journey south.

We were super excited to try this project at home, and it's really easy to do, and fascinating for children and (creature-keen) adults alike. I ordered a kit to help us do it the first time around, to make sure we didn't make any mistakes. The caterpillars arrived in the post like this:

Caterpillar babies!

We got our kit from Insect Lore. The pot arrives with the caterpillars in it and that brown substance at the bottom which is their food. These babies grew astonishingly quickly - within a week they were this large:

Hungry caterpillars
Although the full life cycle process takes just under two weeks, so it requires a lot of patience for young children. I kept my two occupied with books, namely Caterpillar Butterfly by Vivian French, and the less technical old favourite The Very Hungry Caterpillar, which we also have in pop-up format (scroll to the end....).

Book recommendation: Caterpillar Butterfly
We also listened to musician Poco Drom's song Wriggle Wriggle Out a lot. If you haven't heard this already, it's free to listen to online and you're in for a treat! I recommend catching Paul at a live gig one day too.. With the kids of course!

As the song goes, we waited and we waited, and we watched patiently every day for the caterpillars to become chrysalides, which they did, one at a time.


Then, almost a week later, we had five chrysalides instead of five caterpillars. The kids were very excited about watching them pupate, and interested in the silk webs being weaved by the caterpillars, and their little round droppings..


One morning I heard a mysterious tap-tap-tapping noise in the living room, and found that it was coming from one of the chrysalides, which was shaking and hitting itself against the inside of the pot. Initially alarmed, I consulted the leaflet that came with the kit and found that chrysalides sometimes do this to ward off predators. Perhaps a fly or spider had gotten too near to the pot. I thought it was a shame that the children had missed it (the tapping stopped after a few moments), but I did manage to get a video of the phenomenon to show them:


Once they'd all become chrysalides we transferred them to an enclosed net, in which we left some fruit and flowers sprinkled with sugar water for each butterflies to feast on as it emerged from its pupa. I don't have any photographs of this stage because it was too tricky trying to get shots of them through the net, but it was pretty cool watching each chrysalis crack open to allow the butterfly out! Most of them seemed to do it overnight, but were still completing the process in the morning. The butterflies emerged over a few days, and then we took them into the garden to let them fly free.

Feasting on Passiflora (passion flower)


In case you're unsure about whether this is a good nature project, natural history writer Patrick Barkham argues that ‘we’ve released butterflies since Victorian times’ and that there’s little harm in continuing the trend today. Personally I think it's an amazing way to teach children about the life cycle of a caterpillar, and to bring out the naturalist and wildlife-lover in youngsters.





Fly, my pretty!
If you want to try this at home, you still have until mid September this year, which is the latest these butterflies can be released. I'm thinking of taking in some cabbage whites, as our garden is overrun with them at the moment. Earlier this year I thought it would be fun for the kids to plant wild nasturtiums, but they sort of took over the garden, and then caterpillars took over eating them, so I just decided to leave nature to it. They were VERY hungry caterpillars:

Look closely and you'll see at least 20 in this photo! One per stem
If you don't want to order a kit, here's what you'll need to do this at home. Use a jar or plastic pot with small holes in the lid, to enable the caterpillars to breath. I've seen people use mesh as lids but the chrysalides will need something to hang from, so a solid lid is important. Keep the container out of direct sunlight for the duration of their stay. Caterpillars need a lot of food, so fill the container with leaves and the like... Apparently they like nasturtiums... After a few days you should see that they've doubled in size, and soon after that they'll become chrysalides. When they're all in that stage, remove the lid from the pot and clear away the silk and poo in the container, as emerging butterflies can get caught in it. You'll want to release them outside soon after they're all out. The kit I bought came with a mesh net, into which I put the lid of the pot that the chrysalides had attached themselves to. As soon as they're out, they'll need something fresh to much, like fruit or some sugar water - we put sugar water on a passion flower which is how my daughter was able to hold the butterfly. Happy pupating!

Pop up version of The Very hungry Caterpillar

Tuesday, 16 August 2016

Coastal Creature Identification: Rambling Around Rockpools

Wembury, Area of Outstanding Beauty
Down here in Devon we are very lucky to have easy access to so many wonderful varied terrains and beaches that are simply teeming with life, if you know what to look for. Wembury is located on the south coast of Devon, and it's an ideal spot for rockpooling:





Rockpooling is a super fun and easy activity to do with children, and if you pick a good spot for it you'll certainly find plenty of specimens to investigate. Rockpools are diverse and unique habitats filled with salty sea water and plants and animals that are well adapted to weathering harsh living conditions. They have to deal with fluctuating water temperature, salinity and oxygen levels, plus predators. They're really fascinating environments and can help to get children excited about biology, evolution and marine life in a practical but safe way. Take along a few basic tools, including bucket, not a net - this useful infographic tells you all you need to know to plan an expedition:


For the guide I recommend Collins Complete Guide to British Coastal Wildlife, because it has everything you might need to identify in it including molluscs, algae, fish, sea squirts, sea anemones, crustaceans.. You need this guide! But, be warned: it will likely end up looking rather weathered, like this:


May come with added sea water
Velvet swimming crab 

The velvet crab is the largest swimming crab found in British coastal waters, and it's relatively easy to identify because of the red markings around its eyes. We were really excited to find one! This one took a good look at us before scuttling back into the water:



Marine worms

I didn't manage to get a good photo of this worm we found, but there were so many of them and - if I'm honest - we were kind of excited after spotting the velvet crab and had higher ambitions than worms! The kids were interested in what kinds of worms live in water though, and we're going to have a better bash at identifying them next time.

Unidentified worm
Compass jellyfish

Our third and final find was in the actual sea rather than in the rockpools, and it was really difficult to get a photograph of this compass jellyfish as it was being thrown around with the waves, particularly since it seemed to spent a lot of its time upside-down:

Compass jellyfish: tricky to photograph!
The compass jellyfish is commonly found in British inshore waters between July and October, and is also easy to identify thanks to the beautiful markings on the outside of its bell, better pictured here:

Image source
The compass jellyfish is not dangerous at all, but if you do get sting by one it's apparently similar to the feeling of being stung by nettles (ouch), and you'll need to rinse the wound in salt water or vinegar and remove any stingers with tweezers. (Urinating on the sting won't help.) Compass jellyfish can grow upto 30cm in diameter, and the one we saw was around 10cm, so possibly just a baby!

And for future ambitions...

I'm really keen to find Calliactis parasitica, a sea anemone that is invariably found attached to Common Whelk shells that are occupied by the Common Hermit Crab. Contrary to the name of this, er, specimen, the relationship between these creatures is symbiotic, not parasitic, as the sea anemone protects the hermit crab from predators with its stings, and benefits from the food thrown up by the hermit crab's movements. And it looks like (drumroll please!) this:
Calliactis parasitica, image from the Collins guide
So, why am I so keen to locate the C. parasitica, aside from the fact that it looks so flippin' cool? Because of the children's book Sharing a Shell, of course, by Julia Donaldson. If you don't already know this book and you have children, you're in for a treat. My kids love this book and I love reading it to them, and not only is it about rockpools, but it also features none other than the anemone and crab pictured above (although it doesn't mention that anywhere in the book and there's also a bristle worm sharing the shell in the story). Still, what better way to teach kids about sharing than using the C. parasitica?? Here's a picture of my firstborn reading the book to herself on the beach after a day spent rambling around rockpools in Wembury:
Sharing a Shell: essential reading for mini rockpoolers
You can also watch a reading of the book on YouTube and hear the Sharing a Shell Song by none other than Donaldson herself, but I recommend getting the book anyway - it's a keeper!

Oh, and it would be cool to see a basking shark too, which can also be seen off the coast of Wembury, but we weren't so lucky this time. The Wembury Marine Centre is also a must for keen rockpoolers, and offers free entry to those with National Trust memberships. They also do identification sessions on the beach.

That's it for my first post on coastal wildlife identification.. Now it's time for another trip to the beach - rockpooling is for adults too!
Rockin' the beach selfie look (groan)

Wednesday, 10 August 2016

So You Want To Be An Astronomer? Tips For Stargazers

Ring Nebula, image by Hubble Space Telescope
No matter how many times I look up, I am repeatedly blown away by what I see. More often than not it's too cloudy out to see anything at all after dark, so it's a great treat when we do get a clear night.

A couple of weeks ago I saw a very bright something sitting very low in the sky, and on a hunch I decided to zoom in on it with my telescope, a Celestron Nexstar 130. As soon as the image was in focus I could tell that it was no ordinary star, but to my knowledge there was also no planet visible in this part of the sky, so what could it be? My guess was: a nebula. I'd never seen a nebula before, so when I added the 7mm lens to get a close up view, I was blown away by the above image, although what I saw was of course less detailed than the powerful Hubble Space Telescope's image.

Through the telescope the Ring Nebula looked like a doughnut-shaped ring, with bright stars zooming around within the ring area, white against the rainbow colours of the doughnut. It was incredible. Although the colours were nowhere near as bright as in the Hubble image, they were clearly rainbow-coloured, and moving around within what looked like a hazy smoke ring. I could have watched it all night, but it was difficult to focus on the nebula for long because it kept moving out of sight of the stationary telescope lens, since the Earth is rotating. This happens with anything viewed through a telescope of course, but is less noticeable with other objects in my experience, for example the moon. Perhaps it was more obvious with the Ring Nebula because it's about 2,000 light-years from Earth and measures roughly 1 light-year across.

How did I know what I was looking at for definite? First, the Ring Nebula is found in the constellation of Lyra, and I could see from my copy of Collins Guide to the Night Sky that I had the right constellation in focus, with the Ring Nebula within range. Second, we know that the nebula is tilted toward Earth, so that lucky astronomers like myself can see the ring face-on. Third, a quick online search of the Ring Nebula confirmed what I could see through the lens.

What is a Nebula? Named after the Latin word for cloud, a nebula is an interstellar cloud of gases and dust. The Ring Nebula is a dying star shedding winds of gas. As Slate.com explains:
"All of this gas was expelled by the star in the very center of the nebula, which was once very much like the Sun (though probably about twice our star’s mass). After billions of years of converting hydrogen to helium in its core and generating fierce amounts of energy, it started to run out of fuel. The star expanded into a red giant, blowing a wind of subatomic particles into space; that’s what makes up the shells of gas you see in the deep image.
Eventually, the star started to contract, heating up and blowing a faster wind that caught up with and slammed into the older material. That’s what forms the brighter inner ring. Interestingly, it’s not actually shaped like a ring: Studies have shown it’s actually barrel-shaped and oriented so that we’re looking down the barrel. It only appears to be shaped like a ring due to our viewing angle."
The Slate piece also features a fascinating video of what goes on inside the ring, which took 90 years and a Eureka! moment to discover.
So, you want to see the Ring Nebula? Here are some tips:

If you have access to a telescope, the Ring Nebula is easily visible in the summer and autumn sky. 

1. Go somewhere dark. I mean really dark, with as little light pollution as possible. I live about 25 minutes away from the nearest city (Exeter, in Devon UK), and it's super dark here at night compared to in the city - but even darker further out. Many of us live in light-polluted areas. Also, get away from tall buildings and trees - aim for a wide expanse of park, or better still a bare hill to get the most out of stargazing, because chimneys and trees can obstruct good views of constellations, and you'll need those to find your way around the sky.

2. Get a good night guide. If you're a stargazer and don't have a copy of the 2016 edition of the Collins guide, I recommend getting one ASAP, as it will help with identification immeasurably. The guide maps the sky according to the time of year, so constellations are relatively easy to pick out depending on the month, and gives descriptions of what you can see depending on whether you are looking north or south, using star maps and charts of planets.

Even if you can get internet access in the field, I wouldn't recommend using your phone to look these things up, because looking at the bright screen will mess up your night vision. A gentle torch and the guide are much better aids (my telescope comes with a red LED light on the battery power pack, which I use to consult the guide from time to time). Seriously, the guide is an essential item.

Modelling the Collins guide, like a true geek
Next, look for the constellation Lyra - so-called because it looks like an upside-down lyre, i.e. like this:

The constellation Lyra, image from MAAS
Consult the guide if you need a hand. Can't find it? Look for nearby constellations on the star map first, then move along. You'll soon get the hang of this. Next, use the constellation to find where the Nebula is - at the top in the image above, see? Apparently you don't need a particularly powerful telescope to do this. Marvel at the most distant object you've likely seen so far in your lifetim - that's what it was for me. Enjoy!!

3. Be patient! If you don't find it, try and try again, or look for something else - the Vega star in the same constellation is the fifth brightest in the sky, and I never tire of looking at the moon through a lens.

4. Stargazing doesn't just happen at night. Use cloudy nights to learn what different constellations look like, which will make finding them at night much easier. This is also a great activity to do with children. Constellations often come with their own stories rooted in history, which can also be fun to learn: in this case the popularity of the lyre when the constellation was named, as the ancient Greeks believed that Apollo gave one to his son, Orpheus, who used it to try to raise his wife from the dead..

When we look up at the night sky, we are looking into the past, at stars that no longer exist and light that has travelled across space for light years to reach us.. And it's the same with constellations: why they were named what they are, how they were mapped by ancient civilizations: these things draw us closer to the past. So marvel at what you see, but don't get overwhelmed. There is much to learn when it comes to astronomy, but we can only get there by learning one constellation, one nebula at a time.

Saturday, 30 July 2016

We are made of star stuff. We are also made of microbes.

I drink tea from a giant mug. For repelling zombies, obviously
If you haven't been following developments on the human microbiome, you're missing out on some fascinating discoveries. I'm currently rereading microbial researcher Rob Knight's Follow Your Gut: The Enormous Impact of Tiny Microbes (pictured above), and if you haven't seen Dr Knight's TED talk already then you're in for a treat. You'll find it at this website, plus an excerpt from Follow Your Gut.

I've seen a lot of theories floating about how eating certain foods will improve your microbiome or how not having a natural birth and giving a baby antibiotics will destroy your baby's microbes (true in a sense, but they also rapidly grow back again). As Knight says, it's important not to jump to conclusions at such early stages in the research, although he does draw some broad potential conclusions himself, which is fine of course as he's a scientist interpreting data, not someone trying to sell you a fad diet.
Excerpt:
It’s tricky to add up all this early evidence into a prescription for lowering your child’s risk of asthma and allergies. I’d sum up the recommendations like this: have a dog (but make sure you start early, ideally prenatally), live on a farm where your kids are exposed to cows and straw, avoid antibiotics early in life, and perhaps take probiotics and breastfeed (although the evidence for those last two is preliminary at present). In general, exposure to diverse microbes, whether through older siblings, pets, or livestock — or through good old-fashioned playing outdoors — seems to help, even if scientists are still sorting out the specific microbes involved. It may be that diversity itself is most important.

I also recommend this Atlantic article on how microbes make malnutrition worse, and how scientists are looking at tackling that, this Smithsonian piece on how microbes adapt to make us stronger, and this Conversation piece about how microbes living in extreme climates can teach us about ourselves.

Finally, a recent study has confirmed a long-running hypothesis: that all of life on Earth descended from a microbe, which has been traced back to four billion years ago. That's pretty impressive. So thanks, clostridia bacteria et al - and to all the scientists involved in this discovery! I can't wait to find out more.

Monday, 25 July 2016

What's The Best Bug Repellent According to Science?

River dips and wild swimming is what summers are for.. Until.. ouch!
Citronella essential oil? Eucalyptus incense? Soaking yourself in garlic?! What's the best anthropod repellent? As ever, I approached this topic with a determination to avoid the woo and discover what might really stop those bugs from taking chunks out of me all summer.

Now, don't get me wrong: I love bugs. But sometimes they can be bitey little buggers! (sorry) If you've been following this blog, or know me in real life, you'll know that I love hiking, river walks and wild swimming. Unfortunately for me, I am one of the 20% of people who are very tasty to the little critters that frequent these place. Some people aren't, depending on factors including blood type, metabolism, skin bacteria and genetics. Lucky them.

Living in Britain means that I don't need to worry about repelling disease-carrying mosquitoes, just every other biting bug we have on this little island. Thankfully there is some sound research to support various options for repelling bugs, which we'll look at here.

Item 1: DEET (diethyltoluamide) is the most common active ingredient used in bug repelling sprays, and it is highly effective. Used safely (i.e. applied to skin at the correct dose), DEET is your best bet when it comes to repelling pesky mosquitoes, and it is safe - in fact it's toxicology has been more closely scrutinized than any other bug repellent. Still, some people find that it irritates their skin, and if you're not so worried about deterring disease-spreading mosquitoes (like me, because I live in England) then there are other repellents worth trying.
Note: The following suggestions are not recommended as effective repellents for use by travellers to disease endemic areas, except PMD.

Plant-based repellents are the alternative option people often turn to, citing that they are 'natural', which is a somewhat dubious claim since many drugs are derived from nature and plant-based repellents still need to be processed/manufactured in order to use them. Also, PBRs can cause dermatitis when applied to skin. Nevertheless, PRBs may be less environmentally damaging*, and can be very cost-effective, so let's look at what researchers have found.

Item 2: Citronella
Essential oils and extracts of citronella (Cymbopogon nardus in Europe and North America) are commonly used as ingredients of plant-based mosquito repellents, despite there being very little research into citronella as an arthropod repellent. What we do know is that citronella-based repellents can protect us from mosquitoes, but only for about two hours after application, unless a specific formula is used. For example, citronella is as effective dose for dose as DEET, but the oil evaporates quickly which reduces how long it lasts and its efficacy. There are ways to increase the longevity of the oil, but this means that protection depends entirely on the composition of the repellent, so it's not as simple as buying any citronella-based repellent on the shelf.
Item 3: Neem
Neem has been tested for repellency against range of arthropods, with somewhat different results. Some field studies from India have shown very high efficacy of neem-based preparations, while other research has found only intermediate repellency. It's likely that undetermined variables in these studies changed the way the repellents worked when they were tested, but in any case we do know that neem offers some protection against nuisance biting mosquitoes and other bugs, even if we're not sure how to attain high efficacy from neem.


Midges love shady areas - so use a good repellent!
Plant-based oils that have shown some repellent efficacy are coconut oil, soybean oil, palm nut oils and andiroba oil, although all of these oils are far less effective than DEET. The most effective oils include thyme oil, geraniol, peppermint oil, cedar oil, patchouli and clove, as they have been found to 'repel malaria, filarial and yellow fever vectors for a period of 60-180 mins'. Again, fixatives or careful formulation are required to improve the longevity of these oils,

Item 4: Lemon Eucalyptus
Corymbia citriodora, also known as lemon eucalyptus, is a potent natural repellent extracted from the leaves of lemon eucalyptus trees. It was found that waste distillate remaining after hydro-distillation of the essential oil was far more effective at repelling mosquitoes than the essential oil itself: Para-menthane 3, 8 diol (PMD) is found in small quantities in the essential oil from the leaves of Corymbia citriodora and offers very high protection from a broad range of bugs over several hours, The essential oil on its own is only repellent for about one hour. PMD is the only plant-based repellent that is advocated for use in disease endemic areas by the CDC (Centres for Disease Control), 'due to its proven clinical efficacy to prevent malaria and is considered to pose no risk to human health'. 

Item 5: Garlic
Despite numerous news articles shouting about its efficacy and contrary to what most alternative remedy websites will tell you, the consumption of garlic is not effective at repelling mosquitoes, and although rubbing it on your skin has 'moderate' efficacy as a bug deterrent, it is not the most effective repellent available, although it probably is the smelliest.

Item 6: Chickens
Yes, you read that right! New research has found that the smell of chickens led to a 90-95% reduction in mosquito counts. It didn't work with all types of mosquitoes, but it's an exciting finding all the same. Since the same chemical compounds that create the chicken odour are also found in citrus peels and Mexican marigolds, this is even something you could safely experiment with at home. At least until eau de poulet hits the shelves, of course..

So, Which Products Are The Best?
The best guide I've found for this is by the independent, nonprofit organization Consumer Reports, who tested several repellent products using live mosquitoes (click the link to see the video of this in action -  you have to admire their dedication!), They recommend products containing DEET, oil of lemon eucalyptus, and picaridin (derived from the black pepper plant) as the most effective at deterring biters. I recommend choosing a product from the suggestions on their website, or else look up bug repellent formulas yourself to see whether they contain the effective DEET-alternatives listed in this blog post. Research like this takes a little time and effort but is well worth it for getting a product that works and for learning to spot the difference between science and woo.

I'm aiming to compile my own list of the best products at some point, so watch this blog space. 

Also, beware of the anti-science crowd, who serve to profit from lies. For example, Bite Blocker is a commercial preparation that appears to be an effective bug repellent, however the company's website tells lies about safety of DEET, claiming that it damages brains (citation needed!) and other scaremongering nonsense, so I would not support or advocate them, personally. 
*Environmental Impact
Which has a lower environmental impact, plant based repellents or synthetic molecules? All of these options need processing, and even naturally-derived plant extracts require agrichemicals to grow them, distillation, extraction... On the other hand, if carefully practiced, cash cropping of plants used for repellents can provide a vital source of income for small scale farmers in developing countries, and can be done sustainably, e.g. when planted in intercropping systems to prevent soil erosion. More research to do at home? Yay!

Sunday, 17 July 2016

The Power of Looking Up: How Astronomy Can Show Us The Bigger Picture

 Waxing gibbous moon, July 2016
What do you see when you look up at night? 

The first time I looked through a telescope, all I saw was stars, but they were stars like I'd never seen them before. Due to light pollution, many of us cannot see what our ancestors once saw when they looked up to the heavens, and no matter how many high-res pictures of planets and stars you see, no matter how many space documentaries you watch, there is nothing like seeing what's out there with your own eyes - well, with aid of a telescope, at least.

The image of our moon pictured above was taken with a phone camera held against the eyepiece of a Celestron Nexstar 350 telescope, but the picture doesn't show the clarity of the moon seen through the eyepiece, which I'm hoping to capture using a better camera. Luckily, you don't need a fancy telescope to be able to stargaze, though I am lucky enough to have access to one, and will be sharing more with you using that here.

So what did I see through the telescope that was so humbling? Carl Sagan often referred to the Earth as 'the pale blue dot', and looking at the moon so close up, in such detail, at Lunar craters and maria and old lava flows, Sagan's words really come to life. Perhaps this is why so many great astronomers were also philosophers, inventors, poets. As you gaze at our only permanent satellite, you begin to imagine what the planet Earth must look like to those lucky enough to go to space and see it from a great distance. You get a tiny glimpse of some of what every astronaut must feel when s/he sees this mote of dust we call home, just one planet in one solar system in one galaxy, among the billions of planets, stars and galaxies that make up the universe. It is truly awe-inspiring and humbling, and something I believe every child and adult should experience. All you need is a basic telescope, and a place to stargaze - the further away from light pollution, the better.


My two children are too young to stay up and explore the universe this way, but they are learning a lot through various books and songs (expect a post on this soon), and of course through asking plenty of questions. We've also followed British astronaut Tim Peake's journey, as the kids have been interested in the International Space Station since we saw it fly over at Christmas. Major Peake recently returned from a trip to space where he lived on the ISS in order to conduct crucial research on microbes and blood vessels (among other things), where he ran the London marathon, and took some truly astounding photographs (follow Major Peake's Facebook page to see these and follow his journey). A quick look at his fan page shows how much we love astronauts, how they inspire us, and that we take great pride in knowing that someone from close to home has been in space. And it all starts with looking up, which is why I'm ending this post with Sagan's view of the power of astronomy, taken from his TV show Cosmos. When he speaks of the 'Pale Blue Dot' he is referring to a photograph of the Earth that was taken on 14 February 1990, by the Voyager 1 space probe from a record distance of about 6 billion kilometers. This photograph changed the way people viewed themselves and each other: it was an image that changed the world.


Can you spot it?
More astrophotography from me soon.

Look again at that dot. That's here. That's home. That's us.
On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there--on a mote of dust suspended in a sunbeam.
The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.

- Carl Sagan