An ideal planet for hosting life must meet certain conditions; specifically, its star’s habitable zone must allow life to thrive there.
It should have a surface where liquid water can gather, as well as an atmosphere which protects its inhabitants from harmful solar radiation.
Are there planets similar to our Earth in the universe?
Size
Earth-like planets (also referred to as Earth analogs or Earth twins) are terrestrial planets similar to our own in size and composition, making them Earth twins. Numerous astronomical studies are dedicated to finding these worlds; most notably their discovery requires finding their rocky surfaces and habitable zones as major criteria for finding such worlds; other key attributes may include orbital distance from their star, axial tilt rotation air/water conditions as well as strong magnetospheres.
Today in Nature Astronomy, an international team led by MIT and University of Liege astronomers announced their discovery of an exoplanet just 55 light years away that may support life. It is roughly Earth-sized and located within its host star’s habitable zone – two criteria essential to supporting life on an exoplanet like our own planet Earth. Furthermore, its rocky composition and proximity make this candidate for an Earth-like planet the best candidate yet found.
Astronomers will study a planet’s atmosphere in order to assess if it is suitable for life, using high-resolution telescopes such as NASA’s James Webb Space Telescope. Astronomers will first measure its radius before calculating mass and density with this information and modeling atmospheric properties of this new world.
Tidally locked planets provide more predictable lighting conditions, making them attractive as potential homes for life. Astronomers will also use this method of study in order to gauge its temperature and determine whether or not life exists on this host star.
So far, Kepler has discovered three planets which are less than twice as large as Earth and lie in their stars’ habitable zones; these super-Earths may be made up of rocks or gas; future missions hope that more will be found, which will allow astronomers to gain greater insight into whether any Earth-like planet could support intelligent life forms.
Temperature
There are various factors that can have an effect on a planet’s surface temperature. Distance from the Sun, surface reflectivity (albedo), atmosphere thickness and composition and planet rotation and tidal locking can all have an influence.
Temperatures on planets similar to Earth can range between extremely hot and very cold; scientists are searching for one with an ideal temperate climate that supports life as we know it – the Goldilocks Zone.
Scientists are conducting a detailed examination of exoplanets in search of one suitable for human life. So far they have narrowed down potential candidates to those that are rocky and orbit similar stars like our Sun. Astronomers have even managed to discover several Earth-sized exoplanets within their host star’s habitable zone!
Some planets orbit close to the Sun while others lie further away, and those closer tend to have temperatures most similar to Earth. Venus, for example, boasts similar size and temperature characteristics as Earth; its thick carbon dioxide atmosphere traps heat. Mercury offers similar daytime high temperatures but drops dramatically overnight due to a lack of atmosphere to store heat.
Researchers hope to uncover an Earth-sized planet with temperate weather close to the Sun that could support life; such a discovery would mark an important step forward in their search for extraterrestrial life. An Earth analog or twin planet must have enough room to support life with oceans and lakes as well as areas not covered by either water or land surfaces.
Atmosphere
Atmospheres provide oxygen and pressure that holds water on planets, making life possible as we know it. Astronomers study these atmospheres to understand what conditions allow life to emerge and thrive on other worlds, like exoplanets that have atmospheres such as those orbiting cool host stars known as M dwarfs – these will both be easily characterized using James Webb Space Telescope and Wide-Field Infrared Survey Telescope instruments.
Atmosphere characteristics vary significantly with planet size and mass; temperature differences between an Earth-sized planet and Jupiter can reach up to 2,000deg Celsius; but even within those categories there can be many variations due to dust grains’ sizes and densities which compose its atmosphere – the larger they are, the more heat they trap.
Planets with larger masses tend to be cooler than those with lighter ones; however, that isn’t always the case. Gliese 12b is an example of such an example planet with an extremely thin atmosphere whose surface temperature nears that of an “equilibrium” planet with no atmosphere at all.
Tidally locking of planets depends heavily on their mass. As planets get more massive, their chances of being locked to their stars becomes greater and it will be harder to gain enough energy from them for atmosphere formation.
Although scientists have yet to discover a rocky planet with an atmosphere, they have come closer than ever before. Recently discovered exoplanet 55 Cancri e has an atmosphere made up of carbon dioxide and nitrogen; additionally it orbits its host star in an extremely tight orbit which causes it to be so hot that one orbit of this exoplanet takes less than one Earth day for completion.
But, if we can find a rocky planet with an atmosphere similar to Earth’s, including one with free oxygen levels that match up, the world could resemble our own very closely and might provide evidence for life somewhere out there.
Water
There has been much discussion of whether there could be life on other planets. Many scientists believe that water worlds could provide the ideal place for life to exist on other worlds; these planets consist largely of water with some landmasses surfacing here and there; most can be found throughout our galaxy; one example is Proxima Centauri b, a similar-sized planet which features liquid water as well as having an atmosphere thick enough for life forms to exist on its surface.
For decades, extraterrestrial life has been an area of fascination among scientists, philosophers, and fiction writers alike. Even advocates of space colonization dream of its possibility in the near future; however, finding another planet like our own requires many considerations, including surface conditions, ability to support life support systems, location in solar systems etc.
In order for life to exist on another planet, water must exist on its surface. Furthermore, it is crucial that it is rocky planet and close enough to its star for habitability; furthermore it must have dense atmosphere that protects from stellar radiation and meteor impacts; finally it should fall within the star’s “goldilocks zone”, an ideal temperature range where life thrives without extremes in either heat or cold.
Astronomers have discovered some potential planets that meet these criteria; however, it remains difficult to ascertain whether or not these planets contain life. There are various factors that must be taken into consideration such as orbital stability, surface gravity, distance from star etc that must all be taken into account before making this determination.
Scientists are discovering that Earth-like planets are much more common than previously believed; 100 times more likely. This discovery opens up numerous new avenues for searching for alien life.