Get ready sky watchers, the Perseids are coming! The bright and mighty meteor showers, known as the Perseids, are all set to light up the night sky with their flickers of bright light. The name comes from the constellation they seem to originate from – Perseus.
The Peak of the Shower: Timing
The peak of the shower falls on the nights of 11/12th of August (tomorrow night). The peak, being a slightly broad one, will also cross into the 13th. The showers will last till the 24th of the month, but if you miss the peak, there is no point in hunting out the faint trails later on. Simple advice: Don’t miss it tomorrow!
The showers will be visible through the night. You might want to catch up with them late evening and spend your time with them till night falls. The late moonrise will help ramp up the grandeur of the spectacle.
The moon rises at about 1:30 AM on these two days and by the time the moon reaches anywhere near the zenith, it will be nearly predawn and you’d already be feeling sleepy. The moonrise on the 13th of the month happens at about 2:30 AM and, by that time, the peak of the shower will already have passed. Moreover, the bright planet, Venus and Jupiter, will be close to the moon, so they won’t spoil your view either.
The Origin of the Perseids
The Perseids happen because of the comet Swift-Tuttle. Meteor showers happen when the Earth passes through a path of debris left behind by a comet which has just passed through that region. The debris then fall through the Earth’s atmosphere, burning up in the process and creating the brilliant flickers that we see.
Now, of course, as the years go by, the intensity decreases, because the comet’s orbital period around the sun is way longer than the Earth’s. The next time Swift-Tuttle visits out neck of the woods, it will be in the year 2126. Don’t try to hold your breath that long.
Location Location Location
Choose a location away from the city, if you can. The lesser the light around you and the lesser the fog/smoke in the surrounding atmosphere, the better it is. Of course, all of this means that the nights will get really chilly. Make sure you have a proper blanket, coat and mattress. Spraining your neck is not such a great idea, and thus, reclining against a soft is definitely a good idea.
The shutterbugs will definitely want to get their shots and it will be a good idea to go for long-exposure shots. Patience to make multiple attempts is the key; photo contrast is king!
There exists a fossil of a human skull, labelled 1470, which has been at the center of quite a bit of controversy since its discovery in 1972. This fossil, said to be from 2 million years ago, was different enough from the existing human ancestor at that period—Homo erectus—for some scientists to propose that it belonged to a new species. And thus were formed two warring camps. One said that 1470 belonged to Homo erectus, and the difference could be accounted for by variation within a species. The other camp believed that 1470 represented a remnant of a new species that might have existed along with Homo erectus, meaning that the lineage of current humans might not be as linear as we think it is.
Now, the discovery of three new fossils has strengthened the claims of the second camp. These were discovered by a team led by Meave Leakey (who was also involved in discovering 1470) also near Lake Turkana in Kenya. The new fossils, which are from 1.78 to .95 million years ago, resemble fossil 1470 in skull structure by having similarly large and flat faces. Scientists are saying that the presence of more than a single outlier suggests that 1470 wasn’t just an unusual case in the species Homo erectus, but just one among a number of individuals in an altogether new species, which they are calling Homo rudolfensis. This finding contradicts the belief that our species evolved from the ancestors we share with apes in a strictly linear progression. The authors of this research believe that 3 species existed simultaneously—erectus, 1470 and a third branch— of which erectus eventually evolved to become Homo sapiens.
Not Definitive Evidence
This discovery isn’t convincing the critics, though, who think the evidence is not definite, and that the three fossils could still be diverse members of the same species. For now, our family tree remains murky.
You can unearth more information about this research here and here.
You’ve just seen a few, but you have not seen them all! Curiosity is running at its peak sending back images by the dozens!
Starting from an egoistic shot of its own shadow, Curiosity has gotten down to business and is busy clicking the rugged Martian landscape. Its NAVCAM (NAVigation CAMera) mast has now been raised and it is taking photos with the camera placed there as well.
Here is a small gallery of the images that Curiosity has shot with detailed explanations.
The two photos shows Curiosity’s shadow on the surface of Mars, the left one before the dust has been removed and the right one after dust removal. The mountain in the background is Mount Sharp, the ultimate destination of the Mars Rover.
Note that this isn’t the high resolution image. That’s coming up in a bit.
Landscape portrait in context
This is an interesting image. The colour film, made slightly transparent to put it into the perspective of the landscape, is the actual photo taken by Curiosity’s Mars Hand Lens Imager(MAHLI). During descent, this got covered by a thin film of dust and thus this isn’t the best available photo.
The background has been simulated with the help of High Resolution Imaging Science Experiment (HiRISE)’s images sent earlier. It also incorporates the images sent in by the Mars Reconnaissance Orbiter (MRO) and those obtained from the Mars Express.
Curiosity landing site
This image was taken by the Mars Reconnaissance Orbiter. It simply shows the different parts of the original Curiosity payload, scattered in different parts across the Martian surface.
These are hopefully the first in a long list of images that NASA will obtain. Curiosity also promises to send in colour panorama photos in a day or two!
More than mere images, we hope that the geological profile of the rocks on Mars will be a revelation.
Just when you thought the global warming debate or (depending on the mood that week) climate change debate, couldn’t get any more complicated, new research suggests that trees may be a significant source of the greenhouse gas, methane. That’s right folks, I said trees. You know, those things we plant in droves every Earth Day while singing some happy tune about saving the environment and making the world a better place to breathe. I really don’t mean to sound snarky here, but the poor global warming debate is already hopelessly mired in political rhetoric as it is. Now, we have to contend with research suggesting that trees may be a significant contributor of methane, which is a greenhouse gas.
Now, before you go get the chainsaws and start deforesting the neighborhood, let’s put this new study in context. Researchers at the Yale School of Forestry and Environmental Studies examined 60 trees at Yale Myers Forest in northeastern Connecticut. They tested for concentrations of methane and found that these particular trees had concentrations 80,000 times ambient levels. It is important to note that the trees themselves weren’t the culprit rather, it was a fungus that was eating them from the inside out. This resulted in favorable conditions for methane producing microorganisms called methanogens. Most of these trees were between 80-100 years old and were diseased. Red maples showed the highest concentrations of methane but other significant contributors were oak, birch and pine. Methane levels were also more than 3 times higher during the summer which suggests that summer heat and higher methane output could create a spiral of elevating temperatures.
According to a Yale press release, “These are flammable concentrations,” said Kristofer Covey, the study’s lead author and a Ph.D. candidate at Yale. “Because the conditions thought to be driving this process are common throughout the world’s forests, we believe we have found a globally significant new source of this potent greenhouse gas.” “No one until now has linked the idea that fungal rot of timber trees, a production problem in commercial forestry, might also present a problem for greenhouse gas and climate change mitigation,” said Mark Bradford, a co-author and Assistant Professor of Terrestrial Ecosystem Ecology at F&ES.
This is groundbreaking research because no previous studies have made the correlation between fungal timber rot and increased green house emissions. These findings present a new target for scientists interested in climate change and the potential that aging forests may have on greenhouse gasses. This study was published in Geophysical Research Letters.
All you bird-lovers, it’s time to say hello to a new species in the bird kingdom that has just been discovered. Capito fitzpatricki, discovered in the mountains of Peru, is the latest ‘official’ bird. It has been named after Dr. John Fitzpatrick, director of the Cornell Lab of Ornithology, who himself has previously been involved in the discovery of six bird species.
The Andes in South America is a region with an unrivaled rate of new species discovery; however, a thorough exploration of these regions is hindered by the difficult terrain. In 2008, a group of researchers undertook an expedition to a region of the mountains called the “Cerros del Sira” and chanced upon this colourful bird, also called the ‘Sira barbet’ in a flock consisting of birds of multiple species. After 6 days of exploration in nearby regions, they found more samples of this bird.
Capito fitzpatrickibelongs to the group of birds called barbets. These are tropical, frugivorous (fruit-eating) birds characterized by big heads and bristles below their bills. They are greenish or brown with splashes of bright colours or white and are found in South and Central America, Sub-Saharan Africa and South-East Asia.
How can we be sure Capito fitzpatricki belongs to a different species and is not merely a distant cousin of an existing barbet species? Firstly, it has different plumage characteristics—it has different colourings on its thigh and lower back. Secondly, the DNA sequences of this species were compared with other species in the genera Capito. The divergence, or dissimilarity, in mitochondrial DNA sequence from fitzpatricki and its closest ‘genetic neighbour’ Capito wallacei was in general greater than the divergence seen between two species.
This is one invasion that everyone is delighted about! Man invaded Mars again, with the giant Mars Science Laboratory, Curiosity, the new Mars Rover, landing on Mars today. The whole payload managed to touchdown on the Red Planet, maneuvering itself with utmost perfection. Remember, all of this happened when Earth was blind to whatever was happening on Mars!
Touchdown and cheers
Things worked out like clockwork. The projected times all matched the real times to a few seconds! If you were watching the live stream from the NASA/JPL control room, you’d know the atmosphere in the room as each stage of the rover was accomplished.
There was a loud cheer when the parachute was deployed, a louder one when the back heat shield separated from the main body and the loudest was reserved for when the rover touched down and the magic words ‘Touchdown confirmed’ were spoken out. The almost childish celebrations that ensued involved people hugging each other, clapping frantically and many breaking down in tears. The scene was one of the most emotional ones you’ll ever see – a perfect antidote to the misrepresentation of science and scientists as emotionless entities.
Images and cheers
The next loud cheer occurred when the Odyssey spacecraft took a grainy 64×64 pixel image, just 4 KB in size, showing one of the wheels of Curiosity on the Martian surface. Odyssey soon sent a higher resolution picture, 256×256 pixel wide. The next image was that of the shadow of Curiosity on the surface of Mars. Never have such tiny images generated so much cheer – and tears!
Here is a video of the control room, showing that dramatic scenes.
The publicized $9 billion papers on the Higgs Boson are out! Both the CMS and the ATLAS collaboration at the LHC, CERN have been working against the clock for the last two months to churn out the result that the world was looking forward to – finding the Higgs Boson. Having found the Higgs Boson and announcing it on the 4th of July at Geneva, the CMS and ATLAS collaborations have now released two papers, both reporting that they have improved upon their earlier presented results.
Stating the Obvious
The 4th July conference had already stated that both the CMS and the ATLAS detectors at LHC have found the Higgs Boson, the long sought after particle responsible for endowing all massive particles with mass. The search has been on since the LHC started running more than two years ago. The long time required just goes to show the magnitude of the search – finding the Higgs Boson wasn’t easy. But make no mistake – the Higgs Boson is definitely there!
Now, these two papers, one by CMS and the other by ATLAS, do something on expected lines – they bump up the significance of the result. This simply means that they make the result more concrete.
Improving the Results
To put in the numbers, the CMS collaboration had quoted a significance of 4.9 sigma or 99.99995% surety of the presence of the Higgs at a mass of 125.3 GeV. They have just bumped up to 5.0 sigma, which means that the surety is not 99.99997% but at a mass of 125.5 GeV. The error bars stay as they are. The decay channels of highest significance are the diphoton (or the gamma-gamma) channel, where the Higgs decaying to two photons, or the ZZ channel, where the Higgs boson decays into two Z-bosons.
The ATLAS collaboration publish a more adventurous result. They have bumped up their significance from the 5.0 sigma announced on 4th July, to the 5.9 sigma! That is a huge improvement, but this also raises a few questions about the analysis of data. How is it that the ATLAS collaboration can bump up their significance so very quickly?
Both collaborations have gracefully dedicated their papers to all those who were associated with the Higgs search, but have passed away and couldn’t see the remarkable results.
All of the questions – and there are many – will be answered in an expected conference in December, when the data collected the LHC in the next three months will be analysed and presented. The LHC is set to go into a period of hibernation after that for about 14 months and expected to resume in 2014.
The new Mars Rover, Curiosity, is poised to land on the Red Planet at 0524 GMT on 6th August. There have been no reported delays or corrections for tomorrow. The final path corrections were made today, and now Curiosity is out there on its own. From the time the Rover, called Mars Science Laboratory or MSL, enters the atmosphere to the time it touches down, the whole world will hold its breath. This is to so-called “seven minutes of terror”.
In this article, I’ll give you everything you need to know about the landing – the time, the place and more. Buckle up!
Landing: The Time!
If everything goes smoothly, Curiosity should touch down at 0731 CET (Central European Time) or 0531 GMT. I will take you through these seven minutes before they happen in this article. The times (all in GMT) given below are all expected times as given by ESA and NASA:
Time: T–6 min, 41 sec; 05:24:34 AM
At an altitude of 125 km, the Curiosity payload sheds two 75-kg tungsten weights. This reduces the weight, but it still can’t fly. Perhaps Allen Chen, JPL’s operations for entry, was paraphrasing Douglas Adams when he said “We’re flying like a brick”. The spacecraft’s internal gyroscopes have to all coordinate to keep the spacecraft aimed at the Gale Crater. The target is barely 20 km across.
Time: T–5 min, 26 sec;
The Earthly package is in free-fall. The atmospheric drag increases the surface temperature to about 21000C. Carbon tiles, specially made to handle such high temperatures, protect the precious load inside. Curiosity is nestled safely inside this package.
Time: T–2 min, 28 sec; 05:28:46 AM
The parachute deploys! It’s nearly 16 meters in diameter! The hearts of all the NASA and ESA engineers are in their mouths. The parachutes are one of the parts most likely to fail, even though that failure possibility is quoted at 1%. This will be a real test for the parachutes, since they have only cushioned drops for much lighter payloads. The altitude from ground is 11km and the payload is still travelling faster than sound at an estimated 425 m/s.
Time: T–2 min, 4 sec; 05:29:07 AM
The heat shield separates! The payload starts sensing the ground approaching. The current altitude is just 8 km and the payload is now moving at 125 – 130 m/s, still too fast to make a proper landing. Crucially, three radar antennas switch on and this is how it knows how far the ground is. The data is useful for the craft to adjust its actions. For the first time, the craft has eyes and its guidance system can kick in.
Time: T– 53 sec; 05:30:40 AM
The back-shell separates. Finally, the world gets a glimpse of the new Rover! The back-shell flies off with the parachute! Curiosity drops down towards the surface, cushioned by the thrust of eight retrorockets. The altitude is less than 2 km from the surface and the craft is moving at a speed of 80 m/s.
Time: T–20 sec; 05:31:17 AM
The sky crane is deployed! This is a complete transformation from previous landings by NASA. So why this sudden transformation? Simple – Curiosity is just too heavy. This calls for a new arrangement – the wheel suspension system can be used as a landing gear. The main craft, Curiosity, then drops down as a thread unspools from the sky crane. The craft gently drops down at a nice pace of 0.75 m/s.
Time: T–0 sec; 05:31:37 AM
Landing: The Place
The site of the touchdown is Gale Crater. The crater is 154 km wide, but the target area is just 20 km. The High Resolution Stereo Camera (HRSC) on the Mars Express spacecraft has just sent back a very interesting picture of the landing area. The image is a false colour image as shown below:
The image suggests the presence of water-based minerals, which might form the basis of life. The lower elevated areas are shown in purple and this forms the target landing area. But don’t miss out on the elevation right in the middle – it’s called Mount Sharp and rises to 5.5 km above the crater floor. Scientists want the rover to land closest to this mountain, as the geologic features there are “very interesting”. The rover will land in the depression, scour around for interesting geologic artifacts and then trudge towards the elevation.
The Eyes and Ears of Curiosity
Meanwhile, the Mars Express will be eyes and ears of the Mars Science Laboratory. The Mars Express Lander Communication (MELACOM) will be switched on at 0205 GMT on 6th August, long before the touchdown.
M-Ex starts recording
Radio signals transmitted by the Mars Rover will be recorded by the Mars Express starting from 05:09 to 05:37 GMT. (For CET times, just add two hours.) This is when the MELACOM receiver switches off and the Mars Express starts off from the dark area of Mars to point at Earth.
M-Ex starts transmitting
The Mars Express starts transmitting recorded signals back to Earth at 06:10 AM (GMT). The data will be transmitted for over 40 minutes with the transmitter shutting down at about 06:42 AM. The only thing left to do for ESA is to transfer the data to NASA.
The Final Words
We’ll be there with you when the massive Mars Rover, weighing in at 900 kg, touches down on the surface. The leaps made have not only been in terms of the technology packed in the machine, but also in the new ways devised to land a very heavy craft precisely on the surface of another planet. The unexpected hurdle came in the form of the black out for the “seven minutes of terror”, during which Curiosity will land, but NASA will be completely blind to it.
So what can go wrong? Charles Bolden, NASA administrator, has a very simple answer – “All sorts of things can go wrong”.
What about all the simulations of worst-case scenarios, rigorous testing of each part and lessons learnt from previous missions? Shouldn’t they be enough? Steven lee, mission’s control systems manager, working in JPL has the perfect closing line:
Probably the overall biggest risk is our lack of imagination.
Women are known to live 5 to 10 years longer than men. One of the reasons for this asymmetry has been revealed.
How We Get Our DNA
It is fairly common knowledge that we inherit half our DNA paternally and the other half maternally. There is actually a correction to that — we inherit half of what is called nuclear DNA from our fathers and the other half from our mothers.
Mom, Give Me My Mitochondria!
The DNA that encodes for most of the genes in our body exists in a compartment of the cell called the nucleus. Almost all the diverse functions in our body in some way lead from the sequence of this DNA. Almost all, but respiration. Respiratory genes of our body lie in another compartment of the cell called the mitochondria. The mitochondria comes with its own set of DNA, and this set is inherited directly from the mother. This is because of the mechanism of fertilization. It is only the nucleus of the sperm that fuses with the mother’s egg cell to produce the first baby cell (also called a zygote).
How Are We Protected From Mutations?
Moving on to mutations, evolution selects against a mutation in a gene if it is harmful to the organism. A little simplistically, if a mutation in a gene affects the mother or the father, then it will have less chances of being passed on to the next generation. An extreme example of this would be if an individual has a mutation that causes individuals to die young. Since people with these mutations would reproduce less, it would never be allowed to become widespread in the population.
When you bring mitochondrial genes into the mix, you get something interesting. Mutations in the mitochondrial DNA that affect only males have no harmful effects in mothers. Thus, a woman with such mitochondrial mutations would simply pass on such mutations without any “weeding” taking place. Over generations, you could see an accumulations of such mutations which would affect males, but they would have no selection pressure on them because of their transmission through females only.
Fruit Flies Show Anti-Male Mutations in Mitochondria
This is exactly what researchers have found in fruit flies. They compared 13 populations of fruit flies with identical nuclear DNA but different mitochondrial DNA. After growing them in identical conditions, they computed longevity of these populations and found that female flies lived longer (on average, they lived 11 days longer than male flies— a significant difference in the fly life span!). Thus, sex-specific patterns of aging are because the mitochondrial DNA have mutations that affect some component of aging in males, but are either neutral or beneficial in females. Mitochondrial genes are often linked to aging, because respiration leads to the production of toxic substances that can damage our DNA. Respiration is ‘oxidising’, that’s why we hear so much about using anti-oxidants to prevent aging.
This points to a sex-specific sieve that could contribute to differences in life spans between the two sexes. You can read about this research here.
It’s not just our bodies that have left-handedness and right-handedness. It has long been known that molecules within living organisms also possess the property of asymmetry, also called chirality. This simply means that a molecule does not match its mirror image. Thus, while the proteins in our body are composed of amino acids that are left-handed, the sugars are right-handed.
The Importance of Handedness in Life
This preponderance in one type of handedness has long been considered as essential property and prerequisite of ‘life’ itself. This is mainly because inorganic substances contain roughly equal quantities of both left-handed and right-handed molecules. Thus the question of why only molecules with one type of ‘handedness’ would arise in living organisms from a nearly equal distribution of molecules continues to be important in studying the origins of life.
This intrinsic asymmetry is actually being used by space missions, like the ExoMars mission, as an elegant way of detecting traces of life in outer space.
Meteorites found at Taglish lake in Canada, have however shown results that bring this hypothesis to a screeching halt. Researchers have analysed these meteorites for proportions of left- handed ‘L’ and right-handed ‘R’ amino acids, and found an excess of ‘L’ types for some of them.
Meteors as Remnants of a Pre-Life Universe
Meteors represent parts of the extra-terrestrial universe before the emergence of life. Amino acids in these meteors were confirmed to be extra-terrestrial in origin by studying their carbon isotopes. Researchers are proposing that heating in the early days of the solar system melted ice to produce water which dissolved existing amino acids into populations of chiral asymmetric molecules. The amino acids which were found to be excessively present in one form are susceptible to forming asymmetric populations depending on the chirality of the starting amino acid. Thus, a small quantity of an asymmetric molecule could have set off a cascade leading to a highly asymmetric group of amino acids.
“As evidence mounts that [left-handed] excess occurs naturally across bodies in the solar system, any strategies designed to search for life based on looking for this excess require serious rethinking,” saysAlberto Fairen of the SETI Institute in Mountain View, California.
This does NOT, however, in any way, disprove the existence of extraterrestrial life. Chirality is just one aspect of life, and the search of life in outer space will continue.