Largest Batch of Earth-size, Habitable Zone Planets
Our Spitzer Space
Telescope has revealed the first known system of seven Earth-size planets
around a single star. Three of these planets are firmly located in an area
called the habitable zone, where liquid water is most likely to exist on a
by several ground-based telescopes, Spitzer confirmed the existence of two of
these planets and discovered five additional ones, increasing the number of
known planets in the system to seven.
the FIRST time three terrestrial
planets have been found in the habitable zone of a star, and this is the FIRST time we have been able to measure
both the masses and the radius for habitable zone Earth-sized planets.
these seven planets could have liquid water, key to life as we know it, under
the right atmospheric conditions, but the chances are highest with the three in
the habitable zone.
40 light-years (235 trillion miles) from Earth, the system of planets is
relatively close to us, in the constellation Aquarius. Because they are located
outside of our solar system, these planets are scientifically known as
exoplanets. To clarify, exoplanets are
planets outside our solar system that orbit a sun-like star.
animation, you can see the planets orbiting the star, with the green area
representing the famous habitable zone, defined as the range of distance to the
star for which an Earth-like planet is the most likely to harbor abundant
liquid water on its surface. Planets e, f and g fall in the habitable zone of
Spitzer data, the team precisely measured the sizes of the seven planets and
developed first estimates of the masses of six of them. The mass of the seventh
and farthest exoplanet has not yet been estimated.
comparison…if our sun was the size of a basketball, the TRAPPIST-1 star would
be the size of a golf ball.
their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further
observations will not only help determine whether they are rich in water, but
also possibly reveal whether any could have liquid water on their surfaces.
The sun at
the center of this system is classified as an ultra-cool dwarf and is so cool
that liquid water could survive on planets orbiting very close to it, closer
than is possible on planets in our solar system. All seven of the TRAPPIST-1
planetary orbits are closer to their host star than Mercury is to our sun.
planets also are very close to each other. How close? Well, if a person was
standing on one of the planet’s surface, they could gaze up and potentially see
geological features or clouds of neighboring worlds, which would sometimes
appear larger than the moon in Earth’s sky.
planets may also be tidally-locked to their star, which means the same side of
the planet is always facing the star, therefore each side is either perpetual
day or night. This could mean they have weather patterns totally unlike those
on Earth, such as strong wind blowing from the day side to the night side, and
extreme temperature changes.
TRAPPIST-1 planets are likely to be rocky, and they are very close to one
another, scientists view the Galilean moons of Jupiter – lo, Europa, Callisto,
Ganymede – as good comparisons in our solar system. All of these moons are also
tidally locked to Jupiter. The TRAPPIST-1 star is only slightly wider than
Jupiter, yet much warmer.
How Did the Spitzer Space Telescope Detect this System?
an infrared telescope that trails Earth as it orbits the sun, was well-suited
for studying TRAPPIST-1 because the star glows brightest in infrared light,
whose wavelengths are longer than the eye can see. Spitzer is uniquely
positioned in its orbit to observe enough crossing (aka transits) of the
planets in front of the host star to reveal the complex architecture of the
Every time a planet passes by, or transits, a star, it blocks out some
light. Spitzer measured the dips in light and based on how big the dip, you can
determine the size of the planet. The timing of the transits tells you how long
it takes for the planet to orbit the star.
TRAPPIST-1 system provides one of the best opportunities in the next decade to
study the atmospheres around Earth-size planets. Spitzer, Hubble and Kepler will
help astronomers plan for follow-up studies using our upcoming James Webb Space
Telescope, launching in 2018. With much greater sensitivity, Webb will be
able to detect the chemical fingerprints of water, methane, oxygen, ozone and
other components of a planet’s atmosphere.
At 40 light-years away, humans won’t be visiting this system in person anytime soon…that said…this poster can help us imagine what it would be like:
There are more stars in the universe than grains of sand on the world’s beaches.
More stars in the universe than seconds of time that have passed since Earth formed.
More stars than words and sounds ever uttered by all humans who have ever lived.
Heavy stars blow up and make heavier elements like gold. So, every bit of gold you’ve ever seen, worn, or touched came from the dying explosion of a star. Other elements made in supernovae include anything on the periodic table heavier than iron
Heavy stars blow up when they start fusing iron. Meaning, the iron in your frying pan, car, and your blood killed a star at least 3 times the mass of the sun.
Some massive stars that die end up compressing all their mass into a star about 6 miles across, or about the size of a city. This is called a neutron star.
To put this in perspective, these stars start out 3 times as big as our sun and all of their mass is crushed into something the size of a city. The space between atoms is squished away, and the protons and electrons combine to form neutrons.
Neutron stars are literally as dense as atomic nuclei
Most stars come in pairs
The most common stellar type is a red dwarf, which is a small, red, dim, cool star.
Honestly, that’s just the first few that come to mind, space is really crazy.
Nasa is currently livestreaming a conference about the discovery of a new solar system !
“Astronomers have detected no less than seven Earth-sized worlds orbiting a cool dwarf star known as TRAPPIST-1.The six inner planets lie in a temperate zone where surface temperatures range from zero to 100C.
Of these, at least three are thought to be capable of having oceans, increasing the likelihood of life.
No other star system known contains such a large number of Earth-sized and probably rocky planets.”
Kepler 452-b is 4-8 billion years old and found 1400 light years away orbiting a G2 type star which is very similar to our sun. It’s orbit is very similar to earth which puts it in the goldilocks zone meaning there is a much greater chance of it containing liquid water which is one of the keys to life. A year on 452-b is 385 days and the planet is about 5% further away from its star than we are from our sun as well as being about the same temperature. Scientists believe it could have the type of climate that supports clouds, oceans and extremely active volcanos.
452-b is about 6 times as massive as earth making the gravity twice as strong. This means any life on the planet would likely be very stocky and we would have a difficult time adjusting to feeling like we were twice our weight. The star it orbits is also 20% brighter than ours and the planet absorbs about 10% more energy than ours.