Search for life on exoplanets more difficult than thought

A new study from the University of Toronto Scarborough suggests the search for life on planets outside our solar system may be more difficult than previously thought.

The study, authored by a team of international researchers led by UTSC Assistant Professor Hanno Rein from the Department of Physical and Environmental Science, finds the method used to detect biosignatures on such planets, known as exoplanets, can produce a false positive result.

The presence of multiple chemicals such as methane and oxygen in an exoplanet’s atmosphere is considered an example of a biosignature, or evidence of past or present life. Rein’s team discovered that a lifeless planet with a lifeless moon can mimic the same results as a planet with a biosignature.

“You wouldn’t be able to distinguish between them because they are so far away that you would see both in one spectrum,” says Rein.

The resolution needed to properly identify a genuine biosignature from a false positive would be impossible to obtain even with telescopes available in the foreseeable future, says Rein.

“A telescope would need to be unrealistically large, something one hundred metres in size and it would have to be built in space,” he says. “This telescope does not exist, and there are no plans to build one any time soon.”

Current methods can estimate the size and temperature of an exoplanet planet in order to determine whether liquid water could exist on the planet’s surface, believed to be one of the criteria for a planet hosting the right conditions for life.

While many researchers use modeling to imagine the atmosphere of these planets, they still aren’t able to make conclusive observations, says Rein. “We can’t get an idea of what the atmosphere is actually like, not with the methods we have at our disposal.”

There are 1,774 confirmed exoplanets known to exist, but there could be more than 100 billion planets in the Milky Way Galaxy alone. Despite the results, Rein is optimistic the search for life on planets outside our own is possible if done the right way.

“We should make sure we are looking at the right objects,” he says, adding that the search for life within our solar system should remain a priority. He points to the recent discovery of a liquid ocean on Enceladus, one of Saturn’s larger moons, as a prime example.

“As for exoplanets we want to broaden the search and study planets around stars that are cooler and fainter than our own Sun. One example is the recently discovered planet Kepler-186f, which is orbiting an M-dwarf star,” says Rein.

Rein says locating a planet in a habitable zone while being able to obtain a good resolution to model the atmosphere will help determine what’s on the planet.

“There are plenty of reasons to be optimistic that we will find hints of extraterrestrial life within the next few decades, just maybe not on an Earth-like planet around a Sun-like star.”

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16 thoughts on “Search for life on exoplanets more difficult than thought”

  1. This article is extremely interesting and gives interesting new ideas to expanding the search for exoplanets. And I think it is a very valid area of research, our planet may have diseases that are killing millions but that’s how nature works. So if now, as most of you propose, we would focus more money on research for HIV or cancer cures would that not just be fighting against nature and create more overcrowding ? Every person would be able to live to ripe old ages, but people also reproduce and with this research causing death rates to go down, if they found cures, the population would sky rocket and overcrowding, food insecurity and pollution becomes just that much more of a problem, then the search for an exoplanet would of looked like a better idea, given that we could reach it. Also the question is that if we could reach another planet with life should we colonize it ? Knowing humans we would inevitably just cause another overcrowded, over polluted Earth, but i would still be interested in seeing another planet with life on it, maybe not to colonize but to observe and see the similarities and differences between our 2 planets.

  2. To u14080542, although research into cures and management of diseases such as is a priority- the exponential rate at which our population is growing will also become a problem in the not too distant future. As it is we have exceeded the number of people that our planet can support, and if we do not find another habitable planet then we may face more severe cases of poverty and economic crisis.

  3. I find these news or articles about Search for Extraterrestrial Intelligence and universe very interesting. It is always nice to know what new planet or any other galactic object is discovered. I understand that billions of Dollars are spent on finding life in other parts of the universe, but I disagree with people saying that this money could be spent on helping people suffering with HIV/AIDS or cancer or other illnesses, solely because I feel that it is not the responsibility of these scientists to help heal the sick people on Earth. They earn their money and give themselves the duty to find out more about the universe, people shouldn’t advise them to use that money for other things that does not involve what they are employed to do.

    As for those who say that there is no life in other planets because it states in the Christian Holy Bible that God gave life to living things on Earth, I disagree because the Bible is only concentrated on Earth, it does not say that God didn’t give life to other creatures in other planets. I think that just because it is not stated in the Bible it doesn’t mean that it is not there.

  4. Finding other planets and life on them is so interesting, but can we really afford to spent so much money on trying to find life where there is already life on earth. All that money could have been spent on economical things like poverty and so on. We as people have so many problems and one could just think what they could have done with that money. I do not think that the exploration of the universe should be a priority. Still i would like to know more about this exoplanets.

  5. Thank you 14064040 and I also completely agree with you statement Pieter de Villiers (u14028949).

    To Nompumelelo (u14185653), I see what your point of few is, but if you look at the research it says that the sun will burn for about 5000 billion years more, I am pretty sure that this would be enough time to still search for and investigate the possibility of another planet where life could be continued if it would at all, and I highly doubt it, be necessary. Thus this type of investigation should not be the priority now as it is not in any way effecting the nearby future, but HIV, cancer, etc. is influencing the lives of millions of people world wide and as 14064040 said, these investigations could make better use of the finances. Sure earth is reaching its capacity, but it is a very selfish argument to make if we say that the research for a “new” earth is to enhance the lives of the earth dwellers, yet we allow people to die because of diseases if the same finances could have been better spent to save them.

  6. The task of finding extra terrestrial life was never going to be a walk in the park. I think that the unpredicted difficulty of the task may actually work in favour of researchers and scientists. Why? Difficult problems and challenges which face scientists today open doors to more advanced technology and can help to improve peoples understanding of partially understood concepts, or even help to build on on knowledge which we previously thought was concrete. So what may look like a setback now, may actually rapidly accelerate our search for inhabitable planets and extra-terrestrial in the not too distant future.

    With regard to SKA in aiding the search for life outside our solar system- I think that the author of the article may have already taken SKA into account when writing this article. The author specifically mentions that no telescopes will be able to help in the foreseeable future. Although SKA would be 100 times bigger than the requirements (according to Dean), and it fills 2 of the three requirements- the third requirement of the telescope being in space may be essential. Seeing that we are looking for objects outside our solar system, interferences from the telescopes surroundings need to be limited. Therefore this may render SKA inadequate.

    The search for extra terrestrial life has always intrigued me and I therefore feel that the money spent on projects in this field are well worth it- especially since success in these fields will benefit all people.

    Thanks for the informative article on the progress of our quest for aliens.

  7. I totally agree with u14080542. If scientists don’t yet have the right equipment and sufficient research to do effective space exploring, then some of this money that is spent on voyages and to build new telescopes, can rather be used in other fields that will show more positive results. I still believe that space exploration can benefit us greatly but first we should resolve some issues that we are facing on earth. Space exploration is extremely expensive and does not always (most of the time) lead to positive and useful results. One example is that just two weeks ago a $280 million mission was brought to an end (LADEE-explorer), and there are several other space exploration missions that is also costing millions and not resulting in enough positive results and new information.
    I truly stand behind space exploration and it fascinates me a lot, but surely there are other things that can use some of these millions more effectively.
    By : 14064040
    Date: 2014/04/30

  8. I find it interesting that we can make use of techniques and telescope to determine the distance, size and temperature of planets as well as to be able to determine what the exoplanet’s atmosphere is composed of. But with the techniques we use we cant determine what the atmosphere is like, and so we cant determine whether the exoplanet’s is capable to maintaining life. New techniques and discoveries must be made to discover life on exoplanet’s. This create new opportunities for the next generation to think outside the box and to discover things we can only dream of.

  9. The study to find life outside our solar system is obviously not an easily accomplished task. Given the limited technology we have available, and how little we actually know of “what is out there”, it will take us years, even decades, to take that next legendary step for mankind.
    Fortunately researches have been working on this field for years. Scientists have been exploring stars outside our solar system that is a bit smaller than our sun (called M dwarfs or red dwarfs) with the hope of finding high levels of oxygen. Unfortunately, using the Hubble Space Telescope, results show that the ultraviolet (UV) properties of these small stars are quite different from those of the Sun. They did show high levels of oxygen, but with the absence of life.

    With biblical reverence; God created the earth and all its surroundings in the beginning. And it is stated that He gave life to all the creatures (including humans) that walks and flies the earth. There is no indication that He gave life to other planets’ inhabitants. So personally, I think there is a reason that it is so hard to find life on other planets, just for the simple fact that there is no acknowledge able life existent on other planets.

  10. SKA is the abbreviation for Square Kilometer Array. In the article, Rein states that a telescope would have to be built that is 100 meters in size to be capable of having the resolution needed to distinguish between planets that are lifeless and mimic biosignatures of planets that have real biosignatures and planets that have real biosignatures and contain life. The SKA will be a kilometer in size when it is completed and is under construction as we speak. So, the SKA will be more than 100 meters in size and it will be operational in the forseeable future, but it will not be built in space. The SKA fulfills 2 of the 3 criteria that Rein has established for a telescope to be able to distinguish between planets which mimic biosignatures and planets that have real biosignatures. I certainly think that the SKA will allow us to detect exoplanets that contain life in our solar system and in other solar systems that can not be detected at present. After all, SETI (Search for Extraterrestrial Intelligence) will use the SKA specifically to search for extraterrestrials.

  11. One of the most debated topics, without a doubt, is the question of how life formed. The benefits of finding life on other planets stretches far beyond our need to find alien species, and is actually about understanding life as we know it. How planets are put together, how they evolve and how life started. In searching for different planetary systems we can observe planets like earth at different ages, and deduce information to help our understanding of the universe.

    This topic is extremely fascinating and merely touches the tip of the ice burg of what we could discover. It would be naive to say that there is no life out in the observable universe as the vastness is incredible. After all, what is life about? If we are not growing intellectually as a population, our future faces more demise that if we found the cure for cancer. The human race is not sustainable and so we must continue to grow in order to find a balance. Considering this we must first enhance our knowledge as the article hints towards, this is why I admire this article

  12. To u14080542 : Studying exoplanets is as significant as finding the cure for HIV and/or cancer. How? ( you might be asking yourself).

    Well research has proven that the sun will eventually expand engulfing our beloved Earth where most probably mankind would perish. When the search for exoplanets continues chances are, a new planet which is suitable to carry mankind and a fair distance from the sun might be discovered thus mankind would be saved.
    Secondly, the population of the Earth is ever-increasing suggesting that the Earth would eventually not be able to support life here on Earth leading to what is known as environmental resistance where you and me would not survive the living conditions of the Earth. Nonetheless, the discovery of a new planet means an increased life expectancy for all the Earth-dwellers.

  13. I understand that the exploration of the universe to find extra-terrestrial life is a very fascinating field, for me it is as well, but surely it should not be a priority as it is stated in the article. The large amounts of money spent on building new telescopes and sending out voyages to explore can be put to use much better on earth to try and fight against poverty, to get cures for diseases like HIV and cancer that kills thousands of people each year. I am all for exploring and finding out new things, but I believe that scientists should first put their knowledge and money (where does the money for all the space exploration come from?) into trying to save the lives of the people on earth before spending it on something that won’t really add anything significant to our lives.

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