Life, a little further away

This is stretching the definition of "natureza" somewhat, but it is kind of interesting.

Just recently an international* group announced the first "possible" life supporting planet, Gliese 581d**. Not that it DOES have life, just that it could. Gliese 581 is in the constellation of Libra, about 2 degrees north of the brightest star there, Beta librae - look high in the sky, more or less due East from Vitoria, Brazil at 9 o'clock at night at the moment.

At first sight Gliese 581d, orbiting the red dwarf Gliese 581, doesn´t look very much like home. For a start it is about 5-7 times bigger, but more importantly it receives only about 1/3 as much sunlight as Mars, let alone us, so any water there should be frozen solid. It also probably orbits with one side always facing the sun, so has a permanent dark side. However, computer modelling shows that it might be a little more complicated.

A computer simulation of Gliese 581d

A dense atmosphere heavy in CO2, which would match planets in our solar system, would act like a blanket - the famous greenhouse effect. This would raise surface temperatures above the melting point of water, so you would have liquid water, which is essential for life (as we know it).

So what would it be like there? Well, pretty dark at the best of times, and maybe completely dark in some places, with what little light there is being red from the red dwarf star. Lots of CO2 in the air so we probably couldn't breath without masks, and we would feel very heavy, gravity being about twice what we are used to.

Another simulation - we just don't know what it looks like yet

All this is speculation, but it might not be much longer before we know more. Gliese 581d is not that far away - well, it is, 20 light years, but relatively not that far. So probably before long telescopes will be good enough to get at least a light spectrum which would tell us a lot about the atmosphere, especially if it's green!

And... there might be another way. In October 2008 a group in Ukraine beamed a message directly to Gliese 581 using a high powered radio telescope, it should arrive in 2029. An answer would arrive in 2049.


* A French/ English group led by a Swiss using a telescope in Chile. Wordsworth et al 2011, Astrophysical Journal Letters

** It doesn't have a proper name yet, nor does the star. Any suggestions?

Taboa

This is taboa (Typha dominguensis), a common perennial reed. Very very common! Actually, it has spread to tropical and temperate regions all over the world, in marshes and wetlands, even mangrove swamps. It shoots up to about 2 metres tall and releases millions of seeds, so it quickly takes over any area where it becomes established and can be something of a nuisance.

A coastal Restinga marsh near Vitoria, Brazil

Has it's uses though. The fibre is tough and durable and can be used to make baskets and handicrafts, even paper. In Turkey the flower stalk is applied to burns and wounds and apparently works quite well.

Releasing seeds

Perhaps it's most beneficial property though is as a sponge. As it grows, taboa absorbs vast amounts of material from the water around it, most of which accumulates in it's tissues. So taboa beds can absorb Phosphorous from agricultural runoff which would otherwise cause algal blooms, or even heavy metals like Zinc from mining pollution. You just wait and then cut and take away the reeds. There are several studies around the world deliberately making lagoons of Typha dominguensis as a low cost way of cleaning waste water.

It's hard to say whether taboa is such a benefit environmentally. It swamps (as it were) native species in clean water, but cleans polluted water so that other creatures can survive, as well as providing cover for insects and small fish. Anyway, it can be very useful for us humans.

Borboletas

It´s autumn in the southern hemisphere, but it feels like spring with the appearance of flowers and suddenly quite a few butterflies ("borboletas"), the most common of which seems to be this one...

I managed to identify it as the Mangrove Buckeye (Junonia evarete) thanks to the excellent field guides from fieldmuseum org (http://fm2.fieldmuseum.org/plantguides/guide_pdfs/X016-Iracambi-Butterflies.pdf ). As its name suggests, the Mangrove Buckeye rather likes mangroves, in fact from Florida to southern Brazil it is a bane of attempts to reforest coasts with these trees, the caterpillars stripping young seedlings. It's not just mangroves though, caterpillars eat Gervao (Stachytarpheta cayennensis), also know as "Brazil tea", and Sempre viva (Paepalanthus polyanthus) as well as others.

With this diverse food range it can be found far from the coast and mangroves, from Belo Horizonte in the inland mountainous state of Minas Gerais, to Brasilia, over 700 miles from the sea.

Adult females and males can be easily told apart as the males have blue patches (top) whilst the females are more discrete (above). Both have a fast and fairly erratic flight and reportedly prefer the small flowers found in grassland by roads or recently neglected land, certainly I saw these on flowers amongst long grass.

Hunter in the Night Sky

Look to the south and you will see the Southern Cross and Alpha Centauri, but look away from there from November to February and the most conspicuous constellation you will see is Orion, possibly the best known constellation on the planet! Conspicuous and visible from all over the Earth, everyone, from the ancient Egyptians to the Aztecs to the Aboriginal Australians has Orion in their mythology

As everyone knows, Orion is basically four stars, the arms and legs of the Hunter, surrounding his "belt".

A screenshot from Stellarium, 8pm 15th April

The bright red star is Betelgeuse, the strange name coming from the Arabic al-jauza (the name of the constellation) and abet, meaning centre or armpit, so Betelgeuse means "Orion's armpit". Be that as it may, Betelgeuse is huge, if it were placed in the centre of our solar system its surface would extend out to Jupiter. Huge, but not long for this universe being a decaying super giant - when it finally explodes it should be visible from Earth during daylight.

Opposite Betelgeuse is the blue star Rigel, the brightest star in the constellation. Again named from the Arabic, Rigel is a shortened form of Riǧl Ǧawza al-Yusra, which means basically "Orion's left foot". Actually Rigel is two stars, a binary system, which is why it's so bright.

The Belt, three stars together in a straight line, has many names. In Latin America it's known as the Three Marys, a reference to the three biblical Marys who came to the sepulchre of Jesus in the Gospels and were companions of a 4th Mary, the mother of Jesus. Mary Magdalene, Mary of Cleopas and Mary, mother of James. Of course the three stars of the belt are nowhere near each other, they just look that way from here. The star in the middle, Alnilam, is actually 375,000 brighter than the sun, but perhaps fortunately, is 1340 light years away.

The other two stars are Saiph and Bellatrix. Saiph again has an Arabic name, a corruption of saif al jabbar or "Sword of the Giant". It looks faint to us but that's because us humans cannot see UV light, in fact it's as bright as Rigel, but much hotter and most of it's light is ultra violet.

And lastly Bellatrix, the "Amazon star". Bellatrix is "Female Warrior" in Latin, and technically the star is an "eruptive variable" - thus this is perhaps a fitting name for the extremely dangerous, though barking mad, adversary of Harry Potter.

A New Rat

The world always needs more rats (doesn´t it?) and so you will pleased to know that a new one has been discovered! Drymoreomys albimaculatus is orange, hairy and lives in trees.

Actually, Drymoreomys albimaculatus are very, very, rare, even one of the authors of the paper describing them had never seen a live one. They live on the eastern slopes of the Serra do Mar, in the coastal Brazilian Atlantic rainforest from São Paulo down to Santa Catarina, at altitudes of 650 to 1200m. Which means cold damp forest with winter temperatures down to below 0 C, which is probably why they have unusually long thick fur. Although all the ones that have been caught were on the ground, they probably climb trees as they have long prehensile tails and special pads on the palms of their paws for climbing.


Drymoreomys means forest mountain rat, and albimaculatus refers to the white spots they have in their orange pelt. And that's about it. Their life cycle, predators, place in the ecosystem is a mystery. Goodness knows what they eat, probably everything, rats aren´t usually fussy.

The Sky at Night

The night sky of the Mata Atlantica can be as impressive as it's wildlife, and as difficult to see. Of course it depends where you are. By the coast, the tropical heat and humidity tends to cause clouds at night, even after after a day of burning blue sky, whereas in the mountains the clean air and lack of ambient light can open up a vista of millions of stars, or valleys silvered by a brilliant moon.


But to a northern European, the sky is strangely unfamiliar. Orion is still there, but the other stars are rearranged in new patterns. How to identify them? One way is the excellent Stellarium program I have been playing with recently, a free download from www.stellarium.org. The beauty of it is that it's completely customisable. Open the menu by passing your cursor to the left hand side and under [location] input your coordinates and a 360 view of your night sky at that moment will appear (you can find your coordinates in various ways, but the easiest is probably to just put your town/village's name in wikipedia). Find the star you are interested in and click on it to give a name and some basic info. You can also set it up to show the planets automatically, arrange the stars in constellations, increase or decrease the level of background light pollution, and many more things.

So what did I see? The first thing I tried was to ID a constellation I've seen many times from my south facing balcony, but never found in any books. That was because it is in fact 2 constellations, one of which is the most famous of the southern hemisphere.

The Southern Cross is part of the culture of Brazil, on the flag and even the name of a major football team, Cruzeiro. Trace a line from Gacrux, the red one, across to Acrux and extend it about 4.5 times and you are looking, more or less, due South.

Of course the constellations are an optical illusion, Beta crux is 350 million light years away whilst Gacrux is "only" 88. The red colour of Gacrux comes from it being a red giant, a huge, but dying, star, the colour giving it the local name of Rubidia, or "ruby like". In contrast Delta crucis is known as "Palida" or the "pale one". The two pointers, Alpha and Beta Centauri, are technically part of the constellation Centaurus, but on a hazy night, or with lots of ambient light, they seem much more part of a tail to the "Y" of the Cross. Alpha Centauri is very bright, and for two reasons, it's actually three stars, two of which orbit around each other, and one is the closest star to Earth, at 4.2 light years away. Because it is so close Alpha Centauri is found in all sorts of science fiction, from Lost in Space, via Babylon 5 to Avatar, but of course these stars are also found in local mythology, showing local priorities. For the Xingu indians, the Southern Cross is the Curossow bird, whilst Alpha and Beta Centauri are a bird trap.

A life on the ocean waves

Fly to Brazil from Europe or Africa and you will pass over thousands of miles of ocean. As you look down on the endless waves you might reflect on life below - perhaps you imagine you see a whale spouting, or a fishing boat trawling for cod. If you've already experienced Brazil and it's teeming millions of insects, you might wonder if there are any of those down there too. In fact, in all the world there are only 5 species of ocean going insects, all from the same genus, Halobates, and only one of these H. micans, is found in the South Atlantic.

Dias & Lopes 2009. Occurrence, distribution and abundance of Halobates micans Eschscholtz, 1822 (Heteroptera, Gerridae) along the southeastern Brazilian coast. Braz. J. Biol. vol 69.

Halobates micans, the Sea Skater, is in the same family as the pond skaters, and you can see why, with it's long legs and antennae. They live in a purely 2 dimensional world, they can't fly and die if immersed under water for long, though they cover themselves with water repellent and are covered with tiny hairs which trap air, so they are very buoyant. Instead of flying or diving they skate across the sea surface at up to 1m per second, hunting for prey. Well, very small prey, as their bodies are only about 5mm long, so plankton, or perhaps fish larvae trapped on the water surface. The weak link is egg laying, for which they need a solid object. This can be hard to find in the open ocean and they will use anything, really anything, seaweed, dead jelly fish, lumps of petroleum. A plastic gallon jug was found to have 70,000 eggs attached!

Zoologische Staatssammlung München Halobates micans; Eschscholtz, 1822; Meerwasserläufer, Wikicommons

Sea skaters seems to be fairly common, though not near the coast, or too far south where the water is cold. But why does he have the whole south Atlantic to himself? After all there are plenty of insects living in fresh water. Well, salinity is a problem, although the salt marsh mosquito, for example, can tolerate 3x this level. Worse maybe is the problem of breathing. Insects need access to air, at least occasionally, and the rough and tumble of the ocean may drive their little bodies too deep into the ocean for them to return. This is maybe why the only insects there are restricted by super-buoyancy to the surface.


The ocean can, from above, appear like a desert, but for Halobates it's actually worse. Most desert animals can burrow into the sand to escape the heat of midday, or predators, but Sea Skaters are stuck on the surface with nowhere to hide. The sun burns down, with levels of UV that would fry most creatures, but Halobates is shielded by a layer of very dark UV protection in it's upper cuticle, which blocks pretty much all UV light. Then there are fish and sea birds attacking from below and above, which Sea Skaters avoid by jumping several centimetres into the air, away from the water surface.

Put all this together and you start to see why, of over 1,000,000 insect species, there is only one in the vastness of the South Atlantic, the little known Sea Skater, Halobates micans.

If you can lay your hands on Antenna, the journal of the Royal Entomological Society, there is an excellent article on Halobates there. Alternatively, there is a good web resource at http://www.zmuc.dk/EntoWeb/Halobates/HALOBAT1.HTM