Scientists from Belgium’s University of Liege have announced the discovery of an Earth-like planet orbiting within its star’s habitable zone. It was originally discovered using NASA’s Kepler Space Telescope and later confirmed by ground telescopes.
Wolf 1069b offers 16 days of sunshine per year; yet due to certain characteristics it cannot support life.
1. Size
Astronomers have discovered an earthlike planet outside our solar system called TOI 700b that orbits its star at a distance where liquid water could potentially exist, leading scientists to speculate it may support life. TOI 700 b was discovered about 100 light-years away in Cygnus.
Scientists used an innovative technique for finding TOI 700b: measuring tiny fluctuations in starlight caused by tugs on its planets that cause them to change shape, such as tugging. By doing this they were able to track how TOI 700 b was dimming the star in an orderly pattern which allowed them to pinpoint its mass and properties.
TOI 700b takes roughly 10 days to orbit its star, and is likely tidally locked, meaning only one side faces towards its sun at any one time – making one side perpetually day and the other always night – but this may actually help protect against harmful radiation, according to New Scientist.
TOI 700 c is the third planet in the TOI 700 system and 2.5 times larger than Earth, taking more than 40 days to orbit its sun and likely being tidally locked, although warmer weather might make it more habitable than TOI 700 b.
These two newly identified Earth-sized exoplanets join several others that have already been identified, such as those belonging to TRAPPIST-1 system. Modeling suggests three TRAPPIST-1 planets exist within its habitable zone – TRAPPIST-1e, f, and g are particularly promising candidates for hosting extraterrestrial life, and future telescopes such as Large Interferometer for Study of Extraterrestrial Environments (LISSE) will allow further examination.
Before we can firmly state that any Earth-like exoplanet actually harbors life, scientists need to conduct more extensive analyses on their composition and atmosphere before making such a claim.
2. Temperature
Scientists have recently made a remarkable discovery: an exoplanet similar to Earth has been discovered orbiting a nearby star, becoming the closest equivalent ever discovered so far and marking only the second planet like it in a system likely capable of supporting life. Astronomers were able to pinpoint this planet using two methods; both used data from NASA’s Transiting Exoplanet Survey Satellite (TESS) while another used information from European Southern Observatory’s High Resolution Planetary Imaging Spectrograph (HARPS).
GJ 1132b is an unusual planet – more expansive and heavier than Earth – but otherwise similar to our home planet in terms of composition and atmosphere. This discovery marks an exciting new chapter in the search for Earth-like environments with conditions conducive to life.
However, this world likely would not support life as we know it. The temperature would likely be about one thousand times hotter than Earth. That makes it too hot to have liquid water; even rock that forms its surface might not withstand this level of heat.
One additional challenge of being near its star is being subject to radiation flares from time to time, which could remove its atmosphere and alter its surface over time.
Planets made of dense material–such as Earth or the gas-and-rock planets Jupiter and Saturn–may be better equipped to withstand radiation flares than their gas counterparts, although only a handful have been identified that may do so so far.
One such planet lies 1,200 light years away in Lyra constellation and has been identified as Kepler-1649c; this planet was one of the Earth-like ones discovered by NASA’s now retired Kepler telescope and located within its star’s habitable zone where water could potentially exist on it.
3. Atmosphere
Astronomers have discovered approximately 5,000 confirmed planets orbiting other stars outside our own Sun, thanks to telescopes like Kepler Space Telescope and Transiting Exoplanet Survey Satellite. While most are gas giants or superhot worlds, scientists have also managed to discover several that more closely resemble our Earth than anticipated.
As one example, TOI 700e discovered in 2016 is approximately 95% the size of Earth and may contain rocks similar to our planet’s crust. It orbits a red dwarf star within its habitable zone – meaning liquid water could potentially form on its surface – yet what makes this particular planet even more intriguing is that its atmospheric molecules show clear evidence of water molecules.
Although it may seem minor, this discovery is actually a significant milestone in our search for life on other planets. Scientists have once again discovered a planet similar to our Earth in the habitable zone of a nearby star — making this discovery just two years since NASA announced one similar planet was found via observations made with Kepler telescope. Called LP 890-9 b in its press release by NASA, this new world resides 98 light-years from home and shows evidence of terrestrial (rock) atmosphere similar to Earth.
GJ 667 Cc (HD 156384Cc or GJ 667Ccb), was identified in 2015. This potential candidate, which orbits a red dwarf star at the center of our galaxy, has temperatures and composition similar to Earth; however, only receiving one-third as much energy from its parent star than we receive from our own Sun. Thus it doesn’t get as warm or support life like Earth does.
Other astronomers, however, do not believe this world to be suitable for life. Given that it is larger than Earth and may receive lots of radiation from its star, supporting any type of life may prove challenging for this planet. Furthermore, most exoplanets discovered to date orbit M-dwarf stars, which tend to be very hot environments with little chance of water life surviving there.
4. Distance
As telescope technology has advanced, astronomers have found more planets similar to Earth in size and composition – an essential condition for life on other worlds. Recently, an international team of researchers announced the discovery of two potentially Earth-like worlds only 16 light years away – TOI 700b and TOI 700c respectively – orbiting TOI 700 star and situated within its habitable zone (range where liquid water may exist on a planet’s surface).
TOI 700 is less than one fifth the size of our Sun, yet its rocky planets resemble Earth in composition and temperature by about 95% – making it one of the closest planets ever discovered by scientists so far. Additionally, they lie within what scientists refer to as the “Goldilocks Zone”, in which temperatures are neither too hot nor cold enough for life support.
These planets were initially discovered using Caltech’s Palomar Observatory 48-inch Samuel Oschin Telescope located in California. After verification with NASA’s Kepler Space Telescope data and another telescope located in Chile, their existence will be studied further by using NASA’s Spitzer Space Telescope’s spectrometer in order to assess if their atmospheres contain chemicals indicative of life.
Scientists note that planet orbits are often elliptical, meaning that sometimes they orbit closer and sometimes farther from their host star. Therefore, it’s crucial to monitor these planets over long periods. TOI 700 b takes 10 days and 21 for TOI 700c to complete one orbit around its star – equivalent times as it takes Earth to orbit around Sun; therefore these candidates could serve as potential earthlike worlds in space.
Astronomers plan to search for other Earth-like planets using both ground- and space-based observatories. For instance, the European Space Agency is developing four free-flying spacecraft called Darwin that will survey 1000 of the closest stars for small rocky planets; one of these called Corot is specifically intended to look for signs of life.