In recent decades, over 4,000 extrasolar planets have been confirmed beyond our Solar System. With so many planets available for study, astronomers have learned a great deal about the types of planets that exist out there and what kind of conditions are prevalent. For instance, they have been able to get a better idea of just how common habitable planets are (at least by our standards).
As it turns out, a surprisingly high number of planets out there could support life. That is the conclusion reached by a team of astronomers and planetary scientists who conducted a study of the possible sizes of habitable zones (HZ) based on stellar classification. After considering many planets could stably orbit within them, they came to the conclusion that stars with no Jupiter-sized gas giants can have as many as seven habitable planets!
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In 1961, famed astronomer and astrophysicist Frank Drake formulated an equation for estimating the number of extraterrestrial civilizations in our galaxy at any given time. Known as the “Drake Equation“, this formula was a probabilistic argument meant to establish some context for the Search for Extraterrestrial Intelligence (SETI). Of course, the equation was theoretical in nature and most of its variables are still not well-constrained.
For instance, while astronomers today can speak with confidence about the rate at which new stars form, and the likely number of stars that have exoplanets, they can’t begin to say how many of these planets are likely to support life. Luckily, Professor David Kipping of Columbia University recently performed a statistical analysis that indicates that a Universe teeming with life is “the favored bet.”
Continue reading “What are the Odds of Life Emerging on Another Planet?”
Scientists have speculated that given the sheer number of galaxies in our Universe – modern estimates are as high as 2 trillion – that there must be infinite opportunities for life to emerge. It has also been theorized that galaxies (like stars) have habitable zones, where star systems located too close to the core or too far out in the spiral arms will be exposed to too much radiation for life to emerge.
But are certain types of galaxies more likely to produce intelligent life? Not that long ago, scientists believed that giant elliptical galaxies – which are substantially larger than spiral galaxies (like the Milky Way) – are a far more likely place to find advanced civilizations. But according to new research from the University of Arkansas, these galaxies may not be the cradles of civilization they were previously thought to be.
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Planets don’t simply disappear. And yet, that appears to be what happened to Fomalhaut b (aka. Dagon), an exoplanet candidate located 25 light-years from Earth. Observed for the first time by the Hubble Space Telescope in 2004, then confirmed by follow-up observations in 2008 and 2012, this exoplanet candidate was the first to be detected in visible wavelengths (i.e. the Direct Imaging Method.)
Over time, this candidate got fainter and wider until it disappeared from sight altogether. This led to all kinds of speculation, which included the possibility of a collision that reduced the planet to debris. Recently, a team of astronomers from the University of Arizona has suggested another possibility – Fomalhaut b was never a planet at all, but an expanding cloud of dust from two planetesimals that smashed together.
Continue reading “Fomalhaut’s Planet Has Gone Missing, But it Might Have Been Something Even More Interesting”
In 2021, NASA’s next-generation observatory, the James Webb Space Telescope (JWST), will take to space. Once operational, this flagship mission will pick up where other space telescopes – like Hubble, Kepler, and Spitzer – left off. This means that in addition to investigating some of the greatest cosmic mysteries, it will also search for potentially habitable exoplanets and attempt to characterize their atmospheres.
This is part of what sets the JWST apart from its predecessors. Between its high sensitivity and infrared imaging capabilities, it will be able to gather data on exoplanet atmospheres like never before. However, as a NASA-supported study recently showed, planets that have dense atmospheres might also have extensive cloud cover, which could complicate attempts to gather some of the most important data of all.
Continue reading “How Will Clouds Obscure the View of Exoplanet Surfaces?”
Beyond Earth’s only satellite (the Moon), the Solar System is packed full of moons. In fact, Jupiter alone has 79 known natural satellites while Saturn has the most know moons of any astronomical body – a robust 82. For the longest time, astronomers have theorized that moons form from circumplanetary disks around a parent planet and that the moons and planet form alongside each other.
However, scientists have conducted multiple numerical simulations that have shown this theory to be flawed. What’s more, the results of these simulations are inconsistent with what we see throughout the Solar System. Thankfully, a team of Japanese researchers recently conducted a series of simulations that yielded a better model of how disks of gas and dust can form the kinds of moon systems that we see today.
Continue reading “Gas and Dust Stop Planets From Eating Their Moons”
Located at the heart of the NASA Center for Climate Simulation (NCCS) – part of NASA’s Goddard Space Flight Center – is the Discover supercomputer, a 129,000-core cluster of Linux-based processors. This supercomputer, which is capable of conducting 6.8 petaflops (6.8 trillion) operations per second, is tasked with running sophisticated climate models to predict what Earth’s climate will look like in the future.
However, the NCCS has also started to dedicate some of the Discover’s supercomputing power to predict what conditions might be like on any of the over 4,000 planets that have been discovered beyond our Solar System. Not only have these simulations shown that many of these planets could be habitable, they are further evidence that our very notions of “habitability” could use a rethink.
Continue reading “Here’s What the Climate Might Look Like on Proxima Centauri B”
M-type (red dwarf) stars are cooler, low-mass, low-luminosity objects that make up the vast majority of stars in our Universe – accounting for 85% of stars in the Milky Way galaxy alone. In recent years, these stars have proven to be a treasure trove for exoplanet hunters, with multiple terrestrial (aka. Earth-like) planets confirmed around the Solar System’s nearest red dwarfs.
But what is even more surprising is the fact that some red dwarfs have been found to have planets that are comparable in size and mass to Jupiter orbiting them. A new study conducted by a team of researchers from the University of Central Lancashire (UCLan) has addressed the mystery of how this could be happening. In essence, their work shows that gas giants only take a few thousand years to form.
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Astronomers estimate that in about four billion years, our Sun will exit the main sequence phase of its existence and become a red giant. This will consist of the Sun running out of hydrogen and expanding to several times its current size. This will cause Earth to become uninhabitable since this Red Giant Sun will either blow away Earth’s atmosphere (rendering the surface uninhabitable) or expand to consume Earth entirely.
In a lot of ways, Earth is getting off easy with these predicted scenarios. Other planets, such as WASP-12b, don’t have the luxury of waiting billions of years for their star to reach the end of its lifespan before eating them up. According to a recent study by a team of Princeton-led astrophysicists, this extrasolar planet is spiraling in towards its star and will be consumed in a fiery death just 3 million years from now.
Continue reading “In About 3 Million Years, WASP-12b Will Spiral into its Star and be Consumed”
When it takes to space in 2025, the Wide-Field Infrared Survey Telescope (WFIRST) will be the most powerful observatory ever deployed, succeeding the venerable Hubble and Spitzer space telescopes. Relying on a unique combination of high resolution with a wide field of view, WFIRST will be able to capture the equivalent of 100 Hubble-quality images with a single shot and survey the night sky with 1,000 times the speed.
In preparation for this momentous event, astronomers at NASA’s Goddard Space Flight Center have been running simulations to demonstrate what the WFIRST will be able to see so they can plan their observations. To give viewers a preview of what this would look like, NASA’s Goddard Space Flight Center has shared a video that simulates the WFIRST conducting a survey of the neighboring Andromeda Galaxy (M31).
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