Space exploration, Exoplanets & life beyond Earth Flashcards
How old is the universe?
Approximately 13.7 billion years (about 3 times the age of the Earth).
How old is the Earth?
Approximately 4.5 billion years old.
When was the first exoplanet discovered?
In 1995 the first planet outside of our solar system was discovered i.e. “exoplanet”
How much is the UK Space Industry worth?
Space industry in UK is worth £7bn and has increased c10% during the recession.
How many exoplanets are currently known?
Over 1500 are known about.
800 found in 2014 alone (to date) using the Transiting Technique.
How are exoplanets found?
Direct Imaging Astrometry Transit Technique Doppler Shift Gravitational micro-lensing Disk features Timing (pulsars)
What is Direct Imaging?
Tricky but by blocking out the starlight around the star you will be able to see any planets orbiting. Only enables us to see exoplanets that are orbiting a long way away from its parent star.
What is Astrometry?
Look for the parent star “wobbling” around a barycentre. If there is a large wobble this indicates the presence of an orbiting planet.
What is Transit Technique?
As planet moves infront of the star it will cause a dip in the brightness of the star. You can only see planets that are orbiting the star edge on (i.e. not from above or below).
What is Doppler Shift?
‘Speed guns’ use this technique to measure speed of passing cars. The doppler shift measures the colour change as the object moves towards and then away from us i.e. it tells you how much the star is wobbling and if it wobbles there’s an object orbiting it.
What is Gravitational Micro-lensing?
Optical illusion creates visual copies.
What disk features are looked for when searching for exoplanets?
Disk of gas around a star and the features within e.g. planet forming around the star Vega.
What timing features are looked for when searching for exoplanets?
Timing (pulsars) = slight change in rotation this may be caused by a planet.
What is the Habitable Zone?
Indicates where water could exist (c48 planets found are in habitable zone).
This varies depending on the size & heat of the sun it orbits.
What is a parsec?
3 Light Years.
What type of star has more planets?
Young stars because they are richer in heavier elements.
What bodies in the solar system are candidates for life?
Mars - potentially had life in past.
Europa
Titan
What is the Drake Equation?
The Drake equation is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy.
Currently estimated at 42!
How long has there been life on Earth?
Approximately 100 million years.
How are we searching for ET?
Arecibo Observatory, Puerto Rico.
SETI@home.
What is the Wow! Signal?
In 1977 the Big Ear radio telescope picked up a transmission.
The Wow! signal fitted the profile of an alien transmission.
Other explanations have been ruled out. Transmitters on Earth can’t use the same frequency, and the signal was too narrow to come from natural sources.
Interstellar scintillation, the audio equivalent of a star twinkle, has also been dismissed.
