chemistry – Australian Science

Weekly Science Picks

Magdeline.L — Sun, 28 Apr 2013 00:08:02 +0000

At the top of my list this week would have to be the ISS Commander Chris Hadfield from Canadian Space Agency wringing out a wet towel in zero gravity. If you haven’t watched it yet. Do it now.

The explanation behind what happens is more in depth than “magic”. Cmdr Hadfield is right when he mentions surface tension of water. Though it doesn’t explain the chemistry and physics of what is happening and also why he wasn’t worried about the exposed electronics in the ISS. I have to admit I was worried about droplets of water travelling out and into the wiring because water molecules are attracted to one another due to its molecular structure. I should have realised this being a chemist and all.

The arrangement of oxygen and hydrogen of water results in a slightly positively charged area and a negatively charged area so water molecules arrange themselves where opposites attract. This even holds in zero gravity.

What I especially like about Cmdr Hadfield is that he includes people on Earth in his daily routine on the ISS. He replies to people’s tweets. I personally got a kick when he retweeted one of my tweets. Real time communication with an astronaut on the ISS. That’s awesome. He also includes school students allowing them to ask him questions. If you’re on Twitter and he isn’t someone you’re following, go find him at @Cmdr_Hadfield.

At the end of this week, a news story broke of how radioactive bacteria could potentially used to treat metastatic pancreatic cancer, that is where the cancer has spread to other parts of the body. The bacteria used was Listeria monocytogenes which is a member of a bacterial family that can cause serious infections and health complications. The good news though is that immune system normally gets rid of Listeria.

One reason why tumours grow is that they suppress the immune system so scientists thought to exploit this hoping that introduced Listeria would concentrate in tumour sites and deliver targeted radiotherapy. They introduced Listeria bacteria dosed with radioisotopes in mice with pancreatic cancer.

The results are really promising. The mice that received this treatment had 90% fewer cancer tumours in other areas of the body than those who had received radiotherapy and saline. The original cancer in the pancreas though was unaffected. It’s early days and it’s a long way from human trials. There is still the need to explain what was observed in this trial and what remains unknown is the effect of radiation on healthy organs.

Pancreatic cancer is the 6th highest cause of death for all cancer types in Australia, and only about 6% of people with this cancer survive 5 years after diagnosis compared to a 5-year survival of 88% for breast cancer, 93% for thyroid cancer and 19% for lung cancer. Currently there are very few treatment options available.

Cite this article:
Lum M (2013-04-28 00:08:02). Weekly Science Picks. Australian Science. Retrieved: May 06, 2024, from http://australianscience.com.au/space/weekly-science-picks-28/

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Searching for Life on Titan

Lauren — Wed, 13 Feb 2013 07:53:51 +0000

Titan against Saturn. Credit: NASA

Discovered in 1655 by Dutch astronomer Christiaan Huygens, Titan is one of Saturn’s 62 moons, named for a race of giants in Greek myth who were Saturn’s brothers and sisters. Over 5000 km in diameter, it’s roughly twice the size of our own Moon and is one of the largest moons in our solar system, second only to Jupiter’s Ganymede. It’s even bigger than the planet Mercury, and is covered with an orange haze that shields the secrets of its surface. That alone makes it interesting, but a glimpse into the workings of the planet makes it more intriguing still—astronomers even believe Titan could harbour life.

In the 1980s, the Voyager 1 and 2 spacecraft flew past Titan; in the 2005 Huygens probe parachuted through its atmosphere and landed on the surface; and the Cassini spacecraft still studies Titan from its orbit around Saturn. Their images and measurements have revealed a vibrant alien world beneath the haze—complete with rivers, lakes, and ice volcanoes.

Credit: NASA

Titan is an incredibly frigid place, with an average temperature of -178 degrees Celsius (-289 Fahrenheit)—too brutally cold for life as we know it, but still of incredible interest to astrobiologists. It’s the only moon known to have an atmosphere—a thick and cloudy one, composed primarily of nitrogen—and it also exhibits weather and changing seasons. The orange haze that shrouds its surface is made up of trace gases such as benzene and hydrogen cyanide, and at the pole closest to the sun, sunlight heats the toxic orange haze and makes it circulate towards the other pole, so the gases concentrating there. Since a year on Titan lasts almost 30 Earth years, each season is 7 years long.

Titan’s seasonal changes. Credit: NASA

However, unlike Earth, its weather system is methane-based—and aside from Earth, Titan is the only object in the solar system to have permanent bodies of liquid on its surface, including an enormous river system that flows 400km across the moon’s surface to meet a large sea.

River network on Titan. Credit: Cassini

The darkness of the river in the image indicates a smooth surface, which in turn indicates that the river is not a dry bed, but filled with liquid—but this liquid is likely methane or ethane, which are more closely related to gasoline than water. Even though the mechanics seem to be similar, Titan’s weather would be alien to us because the skies fall with methane rain and lakes and oceans pool with liquid methane—but still, this presents possibilities of methane-based life.

Credit: Cassini.

It is also suspected that Titan harbours cyrovolcanoes, which spew water ice and hydrocarbons into the atmosphere instead of lava. Speculations began after NASA’s Cassini spacecraft captured images of a landform on Titan’s surface called Sotra Facula. The images showed three conical features with material flowing from them, their peaks up to 1,500 metres tall, as well as several pits equally as deep. Researchers gravitated towards the idea that these landforms were cyrovolcanoes, as it would help explain a long-standing mystery of Titan’s thick, methane- and nitrogen-filled atmosphere. Calculations show sunlight would have broken the methane down long ago if something hadn’t been replenishing it, and a cyrovolcano is a good candidate—it could erupt methane, dragging it from the planet’s interior into the atmosphere.

Sotra Facula. Credit: APOD.

However, these intriguing surface features could have also been created by weather and meteorite strikes than by volcanic activity, and it is difficult to tell without further data. Researchers believe cyrovolcanoes might be fairly common on the frigid moons of the outer planets—one has been confirmed on another of Saturn’s moons, Enceladus—which is incredibly interesting, because volcanic activity would prove that Titan is an active world, and could increase the likelihood that this huge, distant moon may harbour life. While searing lava destroys life on Earth, ice volcanoes on Titan would provide a way to mix complex chemicals from the surface and the interior. It could bring life forms up to the surface so our instruments have a better chance of detecting them—because fascinatingly, Titan seems to have subsurface oceans.

Further data from Cassini indicates that Titan has a layer of liquid water under its icy outer shell. The evidence is tidal—as Titan orbits Saturn, the planet’s powerful gravitational pull stretches and deforms the moon, like pulling and stretching an elastic band. If Titan were solely composed of rock, this stretching would only cause bulges (tides) of about 1 metre, but instead the moon experiences tides of about 10 metres—suggesting that its interior is not entirely solid. This ocean may not be enormous or deep; just a liquid layer between the solid mantle and the external icy shell would be enough to compress and bulge as Cassini has observed. Since Titan’s ice surface is composed mostly water ice, researchers believe its ocean could be liquid water.

However, just the presence of an ocean alone does not indicate life—researchers think that life is more likely to occur when the water comes into contact with rock, and we can’t currently tell if this exists beneath the surface.

Possible scenario for internal structure of Titan. Credit: NASA

Another intriguing phenomenon is the hydrogen gas flows through its atmosphere, and yet there is a lack of the chemical on the planet’s surface—so how did it disappear? One theory suggests that hydrogen-breathing, methane-based life forms consume the gas, similar to how we consume oxygen on Earth.

Liquid water, a possibly active interior, complex chemistry, a thick atmosphere, seasons, weather… All of these factors reflect the environment of life as we know it, so researchers have long thought that Titan is an excellent candidate to harbour life. None of these factors alone are solid evidence for life—they are just conditions necessary for it—but Titan is a fascinating place deserving of further study. Since its nitrogen-rich atmosphere is similar to Earth, just significantly colder, it also demonstrates how atmospheres of cold moons and planets behave, and thus allows us to speculate about how the atmospheres of exoplanets far from their stars might behave.

But our questions about Titan will remain unanswered until we obtain sufficient evidence to draw conclusions—but to do this, we need data. Two possible missions have recently been proposed. The first is the Titan Mare Explorer (TiME), which would have sent a floating buoy to land in Titan’s methane sea and measure the chemistry and organic composition, study the sea’s interaction with the atmosphere, and basically perform the first nautical exploration of this extraterrestrial ocean. It also would have observed Titan’s methane cycle to help us compare it to the water cycle on Earth. TiME was proposed to launch in 2016, but unfortunately it lost its funding to a Mars mission.

Artist’s concept for the TiME lander. Credit: NASA/ESA

Another possibility, however, is the Titan Saturn System Mission (TSSM), which is a proposed exploration of Saturn, Titan, and Enceladus—focusing on the complex phenomena the Cassini spacecraft has already noted. It is proposed to launch in 2020 and reach Titan by 2029, and during its 4-year-tenure, it would spend time circumnavigating Titan and studying its astrobiological potential. The mission consists of an orbiter and two Titan exploration probles—one that’s basically a hot air balloon, and another that land on the methane seas. One of the proposals for this second lander is the lake-lander of the discarded TiME mission, which will hopefully be included. TSSM, if it goes ahead, would be the first mission to extensively survey the organic chemistry and climate of the land, sea, and air of another world.

If life is detected on Titan, it would undoubtedly be moving and crucial to us as a species—not only because it’s the first extraterrestrial life we have detected, but also because it would behave differently to the water-based, oxygen-breathing life we’ve developed here. Even if life has not yet developed on Titan, the chemistry for life to form is present, so just give the moon four billion years…and who knows?

Cite this article:
Fuge L (2013-02-13 07:53:51). Searching for Life on Titan. Australian Science. Retrieved: May 06, 2024, from http://australianscience.com.au/space/searching-for-life-on-titan/

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The post Searching for Life on Titan appeared first on Australian Science.

Weekly Science Picks

Magdeline.L — Sun, 25 Nov 2012 00:15:18 +0000

The midlife crisis is more complicated than first thought. It might be time to stop blaming troubled marriages and feeling obsolete in a sea of younger colleagues. A study published in the Proceedings of the Natural Academy of Sciences has revealed that chimpanzees and orangutans also experience a midlife crisis.

Having a midlife crisis may not just be the result of a troubled marriage or the thought that life may be halfway over. It might be part of primate biology. That’s right, hardwired into us.

Economist Andrew Oswald told ABC Science that it might be beneficial.

“Maybe discontent lights a fire under people, causing them to achieve more for themselves and their family.”

A shiny new red sports car might just indeed lead to better things.

Danielle Spencer runs a science club at Mitchelton State School in Queensland and explored where gender stereotypes in science began. Where does the perception that men do the “hard” sciences and women do the “soft” sciences come from? A group of 45 primary school students were surveyed and it was found that a majority of students thought that science was accessible to both genders.

When asked why there are more men than women in engineering roles, the students responded with gender based answers like “Girls like dancing and other jobs.” and “Women are more suited to caring and developing jobs like childcare and nursing.”. There was no response that challenging this observation. This was despite 75% of the group thinking that science was accessible to them. It is disheartening to hear.

Students were asked whether their science club should be split into a boys only and girls only science club, there was overwhelming support for a combined science club. There was an appreciation and acknowledgement that irrespective of gender, everyone had a valuable contribution. At the moment this cohort of students believe that science is something that everyone can do. The question remains though, how do we get adults to believe this?

As this week drew to a close, attention focused on NASA’s Jet Propulsion Laboratory in Pasadena, California. A story broke at NPR reporting that the Curiosity Rover may have found some exciting news. Project Scientist at the Mars Science Laboratory, John Grotzinger was quoted to saying:

“We’re getting data from SAM as we sit here and speak, and the data looks really interesting.”

SAM, the Sample Analysis at Mars is a miniaturised chemistry lab. On board is a Gas Chromatograph, Quadrupole Mass Spectrometer, Tunable Laser Spectrometer as well as sample processing systems that allow heating and chemically treating samples. Normally these instruments would fill the space in a laboratory but on Curiosity it’s around the size of a microwave. SAM is being used to collect information about the past and present chemistry of Mars. As well as this SAM is also identifying organic and inorganic chemical molecules known to be important to life on Earth.

So what has SAM found? Nothing has been confirmed but it does sound like there is something especially when Grotzinger says:

“This data is gonna be one for the history books.”

We will have to wait at least several weeks before NASA makes an announcement.

New Zealand’s volcano, Mount Tongariro made it into this week’s news with an eruption on Wednesday. Luckily there have been no reports of damage or injuries. However, a group of travellers and journalists hiking at the time witnessed and filmed the eruption.

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Weekly Science Picks

Markus — Sun, 18 Nov 2012 00:16:06 +0000

Ah, the weekend! Time to kick back, relax, and look back over everything that’s happened over the past few days. And I’m rather happy to say that some quite interesting things have happened, including the Leonid meteor shower which peaked on Friday night (though if you step outside after dark and watch the sky, you may still see a few stragglers). So what else has caught my eye this week, science-wise?

Well first off, the Curiosity Rover has been busy over on the planet next door. I can’t help but find everything about the Curiosity rover exciting, especially as it’s paving the way for actual manned exploration to another planet. As many people will agree, no matter how sophisticated a rover can be, it will never be as good as a team of properly equipped geologists exploring a site in person. As it turns out, this idea just came a step closer to being reality…

Astronauts Could Survive Mars Radiation, Curiosity Rover Finds

The findings demonstrate that Mars’ atmosphere, though just 1 percent as thick as that of Earth, does provide a significant amount of shielding from dangerous, fast-moving cosmic particles.

Some people may recall the death of an aged tortoise nicknamed Lonesome George, so called because he was thought to be the last surviving member of his species. I know I do, and was rather saddened by it. While it may be an inescapable part of the way life on our planet works, there’s something quite humbling about being forced to simply watch a species go extinct and not be able to do anything about it. But then, was George’s death really the end of the story? As it happens, perhaps not…

DNA tests show Lonesome George may not have been last of his species

“These giant tortoises are of crucial importance to the ecosystems of the Galapagos Islands, and the reintroduction of these species will help preserve their evolutionary legacy,” said Danielle Edwards, postdoctoral research associate at Yale and lead author on the study.

Lisa Grossman at New Scientist discusses the phenomenon of rogue planets – planets roaming interstellar space after being forcibly ejected from their home systems. It’s a concept which I’ve thought about in great detail in the past, as have many others, including astrophysicists, astrobiologists, and science fiction authors.

Astrophile: Lonely planet roams with stellar outcasts

The wanderers are no longer gravitationally linked, but they are headed in the same direction. “Like when you kick a clod of sand, the grains don’t stick together anymore but they have the same common motion,” Delorme says.

In chemistry, I’ve always held a certain fascination with noble gas compounds. Molecules formed from atoms which aren’t supposed to react and form molecules always seemed rather exotic and curious. Several of these compounds have been predicted involving Xenon, one of the heaviest noble gasses. And there may be a lot of Xenon trapped inside the Earth this way…

Professor predicts stable compounds of oxygen and ‘inert’ gas xenon

“In addition to providing a likely solution to the missing xenon paradox and clarifying essential aspects of xenon chemistry, our study may result in practical applications,” says [Artem R.] Oganov. “For example, the ability of xenon to form strong chemical bonds with oxygen and other elements, and to be trapped in crystalline defects, suggests their use as non-classical luminescence centers and active sites for catalysis”.

And to end on a humourous note, XKCD wrote a comic this week describing the Apollo Spacecraft and Saturn V rockets using only the 1000 most commonly used words in the English language. The result was slightly hilarious and rather enlightening about how often writers like myself use words which aren’t in that top 1000. A testament to XKCD’s popularity is how many people in the online space and astronomy communities mentioned it – including at least one astronaut!

xkcd: Up Goer Five

Lots of fire comes out here. This end should point toward the ground if you want to go into space. If it starts pointing toward space you are having a bad problem and you will not go into space today.

Hope you’re having a good weekend!

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