Are We Alone In The Universe?

ARE WE ALONE IN THE .
UNIVERSE?
Humans have been looking for the answer to this question for centuries.., and have likely been asking it for much, much longer. For there to be life outside Earth, of course, the right conditions would have to be in place, beginning with the right planet.

So Far, scientists have Found our potentially habitable exoplanets.

An exoplanet is a planet orbiting a star other than our Sun. To be potentially habitable, it needs to have the right temperature and atmospheric gases.

Planet Earth V The Exoplanets

GLIESE 581 d

PLANET TYPE - WARM SUPERTERRAN
SURFACE TEMPERATURE - 233’K / •40’F
ATMOSPHERE (POTENTIAL) - DENSE ATMOSPHERE WITH LIQUID WATER
ORBIT (YEAR) - 67 DAYS

KEPLER 22 b

PLANET TYPE - WARM SUPERTERRAN
SURFACE TEMPERATURE - 315’K / 107’F
ATMOSPHERE (POTENTIAL) - DENSE ATMOSPHERE WITH LIQUID WATER
ORBIT (YEAR) - 290 DAYS

HD 88521 b

PLANET TYPE - WARM SUPERTERRAN
SURFACE TEMPERATURE - 351’K / 172’F
ATMOSPHERE (POTENTIAL) - DENSE ATMOSPHERE WITH LIQUID WATER
ORBIT (YEAR) - 88 DAYS

GLIESE 667C c

PLANET TYPE - WARM SUPERTERRAN
SURFACE TEMPERATURE - 302’K / 84’F
ATMOSPHERE (POTENTIAL) - DENSE ATMOSPHERE WITH LIQUID WATER
ORBIT (YEAR) - 28 DAYS

EARTH

PLANET TYPE - WARM TERRAN
SURFACE TEMPERATURE - 288’K / 59’F
ATMOSPHERE (ACTUAL) - SIGNIFICANT ATMOSPHERE WITH LIQUID WATER
ORBIT (YEAR) - 365 DAYS

*SIMPLY PUT, A ROCKY PLANET THAT’S SIGNIFICANTLY LARGER THAN EARTH.

Similarity To Earth

Earth similarity index (E51) measures how similar exoplanets are to Earth by looking at composition, size, temperature and atmosphere. 0 = no similarity to earth. 1 = identical to earth. Planets with ESl values above 0.8 are considered earth-like.

0.0
0.1
0.2 --- URANUS/NEPTUNE
0.3 --- JUPITER/SATURN
0.4
0.5
VENUS
MOON
0.6 ---- MERCURY
MARS
GLIESE 581 d
0.7
KEPLER 22 b
HD 855512 b
0.8
GLIESE 667C c
0.9
1.0 --- EARTH

Distance From Earth
GLIESE 581 d---------> 20.2 LIGHT YEARS AWAY
KEPLER 22 b-----------------------------------------------------> 619 LIGHT YEARS
HD 855512 b ------------------> 36.3 LIGHT YEARS
GLIESE 667C c-----------> 22.2 LIGHT YEARS

How Long Would It Take Us To Get There?

Even if these planets had life, however, it would take us a long -very, very long-time to reach them. The Voyager I spacecraft. which has traveled farthest from the Earth so far, does so at a speed of 39.000 mph. That’s 17,207 hears, or 17.21 millennia, to cover one light year. If we could send anything - even anyone - to those planets at this speed. and assuming that they can speed up and stop
instantaneously. here’s how long they would travel:

GLIESE 581 d---------> 347,581 YEARS
GLIESE 667C c-----------> 381,995 YEARS
HD 855512 b ------------------> 624,614 YEARS
1,000,000 YEARS
5,000,000 YEARS
10,000,000 YEARS
KEPLER 22 b--------------------------------------> 10,651,133 YEARS


Could There Be More?

There are hundreds of billions of galaxies in the universe. In our galaxy, there are more than 100 billion stars, each of which is estimated to host 1.6 exoplanets.

In other words, there could potentially be 150 billion unknown exoplanets in our galaxy alone, and many of them are likely to be Earth-like. Whether we could ever get close enough to catch a glimpse of any form of life there, is another question. ARE WE ALONE A IN IN THE UNIVERSE? Humans have been looking for the answer to this question for centuries. . and have likely been asking it for much, much longer. For there to be life outside Earth, of course, the right conditions would have to be in place, beginning with the right planet. So far, scientists have found four potentially habitable exoplanets. An exoplanet is a planet orbiting a star other than our Sun. To be potentially habitable, it needs to have the right temperature and atmospheric gases. Planet Earth V The Exoplanets GLIESE 581 d KEPLER-22 b HD 88521 b GLIESE 667C c EARTH PLANET TYPE WARM SUPERTERRAN* PLANET TYPE PLANET TYPE PLANET TYPE PLANET TYPE WARM SUPERTERRAN WARM SUPERTERRAN WARM SUPERTERRAN WARM TERRAN SURFACE TEMPERATURE SURFACE TEMPERATURE · SURFACE TEMPERATURE SURFACE TEMPERATURE SURFACE TEMPERATURE 233°K / -40°F 315°K / -107°F 351°K / 172°F 302°K / 84F 288 K / 59°F ATMOSPHERE ATMOSPHERE ATMOSPHERE ATMOSPHERE ATMOSPHERE (POTENTIAL) (POTENTIAL) (POTENTIAL) (ACTUAL) (POTENTIAL) DENSE ATMOSPHERE DENSE ATMOSPHERE DENSE ATMOSPHERE DENSE ATMOSPHERE SIGNIFICANT ATMOSPHERE WITH LIQUID WATER WITH LIQUID WATER WITH LIQUID WATER WITH LIQUID WATER WITH LIQUID WATER ORBIT (YEAR) ORBIT (YEAR) ORBIT (YEAR) ORBIT (YEAR) ORBIT (YEAR) 67 DAYS 290 DAYS 88 DAYS 28 DAYS 365 DAYS *SIMPLY PUT, A ROCKY PLANET THAT'S SIGNIFICANTLY LARGER THAN EARTH. Similərity To Earth Earth similarity index (ESI) measures.how similar exoplanets are to Earth by looking at composition, size, temperature and atmosphere. O = no similarity to earth, 1 = identical to earth. Planets with ESI values above 0.8 are considered earth-like. 0.0 0.8 0.9 EARTH LIKE Distance From Earth GLIESE 581 d 20.2 LIGHT YEARS AWAY KEPLER-22 b 619 LIGHT YEARS HD 85512 b 36.3 LIGHT YEARS GLIESE 667C c 22.2 LIGHT YEARS How Long Would It Take Us To Get There? Even if these planets had life, however, it would take us a long - very, very long - time to reach them. The Voyager I spacecraft, which has traveled farthest from the Earth so far, does so at a speed of 39,000 mph. That's 17,207 years, or 17.21 millennia, to cover one light year. If we could send anything - even anyone - to those planets at this speed, and assuming that they can speed up and stop instantaneously, here's how long they would travel: Could There Be More? There are hundreds of billions of galaxies in the universe. In our galaxy, there are more than 100 billion stars, each of which is estimated to host 1.6 exoplanets. . • In other words, there could potentially be 160 billion unknown exoplanets in our galaxy alone, and many of them are likely to be Earth-like. Whether we could ever get close enough to catch a glimpse · • of any form of life there, is another question. visual ly ŞOURCES HTTP://PHL.UPR.EDU/ AND WWw.SPACE.COM 381,995 YEARS- 624,614 YEARS - HD 85512 b 1,000,000 YEARS - 10,000,000 YEARS - 10,651,133 YEARS