Are We Alone? Discovery of Billions of Earth-Like Planets May Hold the Answer

Billions of Earth Like Planets

Study estimates there may be up to 6 billion Earth-like planets in our galaxy.

Earth is the only planet that’s capable of hosting life in the universe. For years, scientists have been hunting for exoplanets – planets beyond our solar system – to discover the probability of life elsewhere in the Milky Way. To be considered Earth-like, a planet must be rocky, about the same size as Earth and orbit Sun-like (G-type) stars. It also needs to orbit in the habitable zones of its star, the distance where the planet isn’t too hot or too cold for life to exist.

Anybody out there?

Over 4,100 exoplanets have been identified with the right size and right orbit of their star to support liquid water and potentially life. That seemed like a reasonable estimate – until now. According to new research published in The Astronomical Journal, estimates and calculations by astronomers at Canada’s University of British Columbia (UBC) who used data from NASA’s Kepler Mission indicate that there are even more Earth-like planets in our galaxy than previously known. Billions of Earth-like planets are orbiting G-type stars in the Milky Way, in fact. The study only considered planets orbiting these stars.

“Our Milky Way has as many as 400 billion stars, with seven percent of them being G-type,” observed study co-author and UBC astronomer Jaymie Matthews in a statement. “That means less than six billion stars may have Earth-like planets in our Galaxy.”

How many Sun-like stars can host an Earth-like planet?

The UBC research team claims there could be an Earth-like exoplanet for every five G-type stars in the Milky Way. Earlier estimates of the existence of Earth-like planets range from about 0.02 potentially habitable planets per G-type star to more than 1 per G-type star. “My calculations place an upper limit of 0.18 Earth-like planets per G-type star,” noted co-author and UBC researcher Michelle Kunimoto. She had previously discovered 17 exoplanets.

The research focused on Earth-like planets likely to be missed when searching because of their small size and great distance from their star. Kunimoto found the planets by using a new method to search for them. “I started by simulating the full population of exoplanets around the stars Kepler searched,” she reported. “I marked each planet as ‘detected’ or ‘missed’ depending on how likely it was my planet search algorithm would have found them. Then, I compared the detected planets to my actual catalogue of planets. If the simulation produced a close match, then the initial population was likely a good representation of the actual population of planets orbiting those stars.”

“Estimating how common different kinds of planets are around different stars can provide important constraints on planet formation and evolution theories, and help optimize future missions dedicated to finding exoplanets,” concludes Kunimoto.

Is there anyone out there? This seminal event in planet hunting may help to one day answer this age-old question.

Read Kepler Space Telescope Reveals as Many as Six Billion Earth-Like Planets in Our Galaxy for more on this research.

Reference: “Searching the Entirety of Kepler Data. II. Occurrence Rate Estimates for FGK Stars” by Michelle Kunimoto and Jaymie M. Matthews, 4 May 2020, The Astronomical Journal.
DOI: 10.3847/1538-3881/ab88b0

8 Comments on "Are We Alone? Discovery of Billions of Earth-Like Planets May Hold the Answer"

  1. It’s exciting that we feel content and finite in our understanding,, but there is so much more to explore and we know a speck of it all. Future is very bright indeed 😉

  2. One very interesting aspect oil f the search for life on other worlds is that the search implies huge issues of humanity’s understanding of basic science laws.
    The most fundamental concept is that physics and chemistry laws are universal. That means there can be no unique event . Wherever conditions are similar, chemical reactions occur alike. So, life can not be unique to Earth since we know Earth is not unique as long as processes are universal.
    But, if life is not found, then it leaves at least three interesting possibilities.
    One is laws are universal but something is actually unique about Earth.
    Another is that what we think is reality is a computer simulation and ccx we are not ‘real’ outside some computer and the simulation contains no other life simulations.
    The third is that life and humanity is the product of a devine event .
    It is fascinating that no apparent life has been found so far and if it is not found soon, we will have to deal with these possibilities.

    • Torbjörn Larsson | July 9, 2020 at 1:42 pm | Reply

      The third listed item is not a possibility, it is superstition.

      But it is correct that processes tend to produce many objects. The short time for life to evolve on Earth suggest to biologists that life should be common among habitable planets.

      However, when you make your list you seem to confuse things, re my first observation above as well as conflating life with human species. Since it took so long before recognizable human species evolved 3-4 million years ago, it suggests to biologists that human language capability is like the elephant trunk – it evolved once, it is “a blue moon” unique trait and will not be common elsewhere.

      This, by the way, plays into finding life. It would be easier if oxygen containing atmospheres could be found, but the atmosphere was oxygenated relatively late so that too will likely be rare. It will not be easy to find life elsewhere, if it would be common.

  3. I would love to go in to space and heard to a earth like payment and find out if there is life

  4. We are not alone! They’ve been around a lot longer than us! There are many diffrent species visiting earth look how technology has changed in the last 2 decades, there are many different types of species some good some bad and all mostly with diffrent agendas take the moon for example!!!!! Look at Mars what ever intelligent life was on there was wipped out ( by nuclear weapons of mass destruction ) people think our creator is God! Im sorry to disapoint you but our creators are alien races where we have been spliced it might sound stupid to you but there watching us!!!!!!!!

    • Torbjörn Larsson | July 9, 2020 at 1:31 pm | Reply

      Any references?

      We don’t expect any of that, the universe is too large and/or you refer to superstition.

  5. Rendani Godfrey Maano | July 9, 2020 at 2:28 pm | Reply

    We are not alone. Growing up in the remote village, I saw what all the village have also seen it. The most beautiful, biggest space ship moving so gently, like tourists exploring the world. I have never seen such a beauty my entire life, now I am 44 years old, I saw it when I was 13 year old around 1990. What shocked me the most about this spaceship is that, it was moving without even a slight sound, very quiet. So quiet that if someone is busy doing his things it can pass without one seeing it. The shape was a V-shaped.The light’s of this spaceship was out of this world, so beautiful and decorated .One seeing all this, you could see that this is so advanced that if it eccellerate, it will dessapear within a blink of eye. One day I watch our jets plane passes by, when I compare it,with our planes they are still small and the speed is very low. We aren’t alone, there are other civilizations out there,believe it or not. Peace🙏🙏🙏

  6. I can accept that we are not alone, but to say that life on other planets exists without that specific proof, well I cannot buy it! SHOW ME THE PROOF or quit saying that it MUST be true…..no proof, no life!

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