Free Republic
Browse · Search
General/Chat
Topics · Post Article

Skip to comments.

Are we being watched? Tens of other worlds could spot the Earth
phys.org ^ | 09-08-2017 | Provided by: Royal Astronomical Society

Posted on 09/08/2017 11:56:13 AM PDT by Red Badger

Diagram of a planet (e.g. the Earth, blue) transiting in front of its host star (e.g. the Sun, yellow). Left: The lower black curve shows the brightness of the star noticeably dimming over the transit event, when the planet is blocking some of the light from the star. Right: How the transit zone of a Solar System planet is projected out from the Sun. The observer on the green exoplanet is situated in the transit zone and can therefore see transits of the Earth. Credit: R. Wells

=======================================================================

A group of scientists from Queen's University Belfast and the Max Planck Institute for solar system Research in Germany have turned exoplanet-hunting on its head, in a study that instead looks at how an alien observer might be able to detect Earth using our own methods. They find that at least nine exoplanets are ideally placed to observe transits of Earth, in a new work published in the journal Monthly Notices of the Royal Astronomical Society.

Thanks to facilities and missions such as SuperWASP and Kepler, we have now discovered thousands of planets orbiting stars other than our sun, worlds known as 'exoplanets'. The vast majority of these are found when the planets cross in front of their host stars in what are known as 'transits', which allow astronomers to see light from the host star dim slightly at regular intervals every time the planet passes between us and the distant star.

In the new study, the authors reverse this concept and ask, "How would an alien observer see the solar system?" They identified parts of the distant sky from where various planets in our solar system could be seen to pass in front of the sun – so-called 'transit zones'—concluding that the terrestrial planets (Mercury, Venus, Earth, and Mars) are actually much more likely to be spotted than the more distant 'Jovian' planets (Jupiter, Saturn, Uranus, and Neptune), despite their much larger size.

"Larger planets would naturally block out more light as they pass in front of their star", commented lead author Robert Wells, a PhD student at Queen's University Belfast. "However the more important factor is actually how close the planet is to its parent star – since the terrestrial planets are much closer to the sun than the gas giants, they'll be more likely to be seen in transit."

mage showing where transits of our Solar System planets can be observed. Each line represents where one of the planets could be seen to transit, with the blue line representing Earth; an observer located here could detect us. Credit: 2MASS / A. Mellinger / R. Wells

=======================================================================

To look for worlds where civilisations would have the best chance of spotting our solar system, the astronomers looked for parts of the sky from which more than one planet could be seen crossing the face of the sun. They found that three planets at most could be observed from anywhere outside of the solar system, and that not all combinations of three planets are possible.

Katja Poppenhaeger, a co-author of the study, adds, "We estimate that a randomly positioned observer would have roughly a 1 in 40 chance of observing at least one planet. The probability of detecting at least two planets would be about ten times lower, and to detect three would be a further ten times smaller than this."

Of the thousands of known exoplanets, the team identified sixty-eight worlds where observers would see one or more of the planets in our solar system transit the sun. Nine of these planets are ideally placed to observe transits of Earth, although none of the worlds are deemed to be habitable.

In addition, the team estimate that there should be approximately ten (currently undiscovered) worlds which are favourably located to detect the Earth and are capable of sustaining life as we know it. To date however, no habitable planets have been discovered from which a civilisation could detect the Earth with our current level of technology.

The ongoing K2 mission of NASA's Kepler spacecraft is to continue to hunt for exoplanets in different regions of the sky for a few months at a time. These regions are centred close to the plane of Earth's orbit, which means that there are many target stars located in the transit zones of the solar system planets. The team's plans for future work include targeting these transit zones to search for exoplanets, hopefully finding some which could be habitable.

Explore further: Finding a 'lost' planet, about the size of Neptune

More information: R. Wells et al. Transit Visibility Zones of the Solar System Planets, Monthly Notic


TOPICS: Science; TV/Movies; UFO's; Weird Stuff
KEYWORDS:
Navigation: use the links below to view more comments.
first previous 1-2021-31 last
To: Red Badger

Don’t you mean marbling? :-)


21 posted on 09/08/2017 1:06:05 PM PDT by Axenolith (Government blows, and that which governs least, blows least...)
[ Post Reply | Private Reply | To 9 | View Replies]

To: Axenolith

Yes, we are the Kobe Beef of the Galaxy....................


22 posted on 09/08/2017 1:06:49 PM PDT by Red Badger (Road Rage lasts 5 minutes. Road Rash lasts 5 months!.....................)
[ Post Reply | Private Reply | To 21 | View Replies]

To: Red Badger

No one would have believed in the last years of the nineteenth century That human affairs were being watched from the timeless worlds of space No one could have dreamed that we were being scrutinized As someone with a microscope studies creatures that swarm and multiply in a drop of water Few men even considered the possibility of life on other planets And yet, across the gulf of space Minds immeasurably superior to ours regarded this Earth with envious eyes And slowly and surely They drew their plans against us

War of the Worlds: The Eve of the War (Jeff Wayne)

23 posted on 09/08/2017 2:04:17 PM PDT by evilC
[ Post Reply | Private Reply | To 1 | View Replies]

To: Red Badger
He's making a list . . .


24 posted on 09/08/2017 5:19:25 PM PDT by Oatka
[ Post Reply | Private Reply | To 1 | View Replies]

To: joethedrummer
Suppose there ARE other beings out there…

Why is it always assumed that they would be way more advanced as we Are?

Assumed astronomical time frames are such that it is assumed that extraterrestrial life would either not yet be intelligent or have been intelligent for much longer than humans have. /evolutionthink

As a practical matter nobody is colonizing alien solar systems. Based on the (putative) impossibility of exceeding the speed of light, even to implement two-way communication is just too hard. And the payoff is hard to envision.


25 posted on 09/08/2017 5:57:26 PM PDT by conservatism_IS_compassion (Presses can be 'associated,' or presses can be independent. Demand independent presses.)
[ Post Reply | Private Reply | To 14 | View Replies]

To: Red Badger

Heavy


26 posted on 09/08/2017 7:50:29 PM PDT by thinden
[ Post Reply | Private Reply | To 1 | View Replies]

To: Red Badger

“I always feel like, somebody’s watching me”

Rockwell?

Coincidence?


27 posted on 09/08/2017 7:55:25 PM PDT by Zeneta
[ Post Reply | Private Reply | To 1 | View Replies]

To: Red Badger
Image and video hosting by TinyPic
28 posted on 09/08/2017 8:12:23 PM PDT by tumblindice
[ Post Reply | Private Reply | To 1 | View Replies]

To: Red Badger

ETs deserve a good laugh too.


29 posted on 09/14/2017 10:19:22 AM PDT by SunkenCiv (www.tapatalk.com/groups/godsgravesglyphs/, forum.darwincentral.org, www.gopbriefingroom.com)
[ Post Reply | Private Reply | To 1 | View Replies]

To: SunkenCiv

HEY! You’re back!.....................


30 posted on 09/14/2017 10:20:36 AM PDT by Red Badger (Road Rage lasts 5 minutes. Road Rash lasts 5 months!.....................)
[ Post Reply | Private Reply | To 29 | View Replies]

To: Red Badger

It’s like the show “Dallas”, I was taking a shower the whole time.


31 posted on 09/14/2017 1:02:56 PM PDT by SunkenCiv (www.tapatalk.com/groups/godsgravesglyphs/, forum.darwincentral.org, www.gopbriefingroom.com)
[ Post Reply | Private Reply | To 30 | View Replies]


Navigation: use the links below to view more comments.
first previous 1-2021-31 last

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
General/Chat
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson