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Does Discovery of Earth-scale Exoplanet Signal Multitude of Planets in the Milky Way?

Cosmos_2_2_2 Astronomers found the first Earth-sized exoplanet three thousand light years away.  The planet was discovered by the science-fiction-sounding method of gravitational microlensing, and shows that there might be far more planets out there than we ever suspected.

The planet is three times the size of Earth, which might sound like a fairly significant difference but you have to remember that in astronomical terms even being within a factor of ten is an amazing similarity.  Every other exoplanet yet discovered has been much larger, many times the size of our own solar system's heavyweight gas giant Jupiter.  This is more to do with the sensitivity of our measurements than the makeup of the universe, however, which is where new tools and methods like the Microlensing Observations in Astrophysics (MOA) telescope-camera based in New Zealand come in.

Gravitational lensing was first used as a proof of general relativity, the idea that a massive object like a star bent space and light around it.  If two stars and the Earth are in precise alignment, the middle star will bend the light from the further star towards Earth, making it appear brighter than it otherwise would - that is to say, 'lensing' it.  Microlensing studies examine these images even more carefully and can reveal planets orbiting the lens star from minute variations in the focused light.

That's exactly how the international team of scientists discovered the Earth-scale exoplanet, which you'd really think they'd give a snappier name than MOA-2007-BLG-192Lb.  It's also interesting because of the star it orbits - which almost isn't a star at all.  At 6-8% of the sun's mass it's tiny, far smaller than any star previously observed to host planets.  There is debate as to whether it can even support fusion reactions, or whether it's a "brown dwarf" - a failed coulda-been star that never sparked into nuclear light and is now slowly trading internal energy for heat until it runs out and goes cold.

This great success in planetary survey techniques raises hopes for the discovery of many, many more planets - not only do we have an accurate and convincingly demonstrated technology, but it seems we have many more places to point it as well.

Posted by Luke McKinney.

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 New Technologies & the Search for Extraterrestrial Life -A Galaxy Insight

 Microlensing reveals mini-star's planet


I've always thought it inevitable that our solar system was not unique. With all the stars in the Universe, it's mathematically impossible that our planet is unique. The discovery of the very first exoplanet should have proven that.

The Drake equation is still there.
Coefficients can be discussed and debated..BUT it is still Valid.

Therefore it is clear that there is a number of other intelligent species around and also this exact galaxy can host many.

I get confused However when we talk about the 'space-time web'...related to 'Civilizations that develop at same time'...

What is the meaning of 'Contemporary'... or Civilizations developing and communicating at 'same time' ??

In simpler words while I tend to understand the Concept of Space-Time web...It is difficult for me to relate living species and developing at different parts of the Milky 'same time'...

What 'same time' means in this case ???

A terrestrial planet distant only 5,000 LY from us in Milky way that we could see say 'Now' ....It is 'not there NOW' ...the better concept should be 'It WAS There...some 5,000 Y-agò' ........Correct ????

PLS clarify the meaning of 'contemporary' at 'different observation points' (I tend to understand the concepts predicated by Einstein on this topic)...but that concept is everythibng BUT unclear to me when we read 'Exo-planet discovered at this and that star....NOW'.

A good article would clarify my understanding of 'NOW'


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