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cooper and george

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Europa is thought to have subsurface liquid water. Scientists hypothesize that Europa's hidden ocean is salty, tidal, and causes its ice surface to move, resulting in large fractures which are clearly visible in the above image. Although Europa is thought to have the ingredients needed to support life - water, energy, organic compounds - it lies outside of our solar system's habitable zone. (Image Credit: NASA/JPL/Ted Stryk).

Currently, Earth is the only known planet (or moon) to have consistent, stable bodies of liquid water on its surface. In our solar system, Earth orbits around the sun in an area called the habitable zone. The temperature, along with an ample amount of atmospheric pressure within this zone, allows water to be liquid for long periods of time.

Evidence points to water on other planets in our solar system. In 2015, NASA confirmed that liquid water flows intermittently on present-day Mars. Also in 2015, scientists used data from NASA's Cassini mission to discover that a global ocean lies beneath the icy crust of Saturn's moon Enceladus. Scientists believe that Jupiter's moon Europa has a subsurface ocean as well.

Finding liquid water beyond our solar system may indicate the existence of extraterrestrial life. Using data collected by NASA's Kepler spacecraft and the W.M. Keck Observatory, scientists have determined that 22 percent of solar-type stars in our galaxy have Earth-sized planets in their habitable zone and could host life. Some of these planets are a mere 12 light years away and can be seen with the naked eye in the night's sky.

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national oceanic and atmospheric administration

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Currently, Earth is the only known planet (or moon) to have consistent, stable bodies of liquid water on its surface. In our solar system, Earth orbits around the sun in an area called the habitable zone. The temperature, along with an ample amount of atmospheric pressure within this zone, allows water to be liquid for long periods of time.

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there are some sightings but people don't know if its true
guy nintendo and nick

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George and cooper

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In 2040, Americans plan to vote in a U.S. presidential election. Japan promises to stop using nuclear power. Britain's Prince George will turn the ripe age of 27. And, as the interactive above demonstrates, the world is likely to find alien life. It could happen even sooner, depending how many civilizations are out there to be found. To understand why this is, it helps to know about someone name Frank Drake.

Drake is the least lonely man on Earth-if not in the entire galaxy. Most of us are reserving judgment on whether there is intelligent life on other planets; we haven't even found bacteria yet, much less a race of aliens with Internet service and takeout food. But Drake, an astrophysicist and chairman emeritus of the California-based SETI (Search for Extraterrestrial Intelligence) Institute, has no such doubts.

It was in 1961, when he was working at the National Radio Astronomy Observatory in Green Bank, W. Va., that Drake developed the eponymous-and now famous-Drake Equation, which calculates how many advanced and detectable civilizations there should be in the Milky Way in any one year. The number turns out to be potentially huge, and while it's admittedly based on a number of Earth-centric suppositions-the collapse of any one of which calls much of the equation into question-all of those suppositions are based in increasingly solid science.

Start with the number of stars in our galaxy, which is conservatively estimated at 100 billion, though is often cited as three times that. Of those 100 billion, from 20% to 50% probably harbor planetary systems-an estimate that becomes more and more reliable as the Kepler Space Telescope and various ground-based observatories detect increasing numbers of exoplanets.

Not all of those exoplanets would be capable of sustaining Earth-like life, so the equation assumes from 1 to 5 in any system could. Of those bio-friendly worlds, from 0% to 100% would actually go on to develop life. And of those world, in turn, from 0% to 100% would develop life forms that we would consider intelligent.

The mere existence of intelligent life forms tells us nothing, however, unless they have the ability to make themselves known-which means to manipulate radio waves and other forms of electromagnetic signaling. Drake estimates that from 10% to 20% of the smart civilizations would clear that bar.

Finally, and perhaps most anthropocentrically, the equation considers how long any one of those semaphoring civilizations would be around to blink their signals our way. A sun like ours survives for about 10 billion years; life on Earth has been around for only about 3.5 billion years, and humans have been radio-capable for barely a century.

If we destroy ourselves in an environmental or nuclear holocaust tomorrow, our signal will go dark then. If we survive for tens of thousands of years, we will be announcing our presence to the cosmos for far longer-and the same is true of all of the other civilizations that live in the Milky Way.

Factor all of this together and stir in a little statistical seasoning concerning our increasing ability to study other star systems for signals, and, as the above interactive shows-the results can vary wildly. If you play the game conservatively-lowballing all of the variables-you might get about 1,000 detectable civilizations out there at any given time. Play it more liberally and you get hundreds of millions. The interactive let's you play that game yourself. Imagine there are 10,000 detectable civilizations and we are likely to find alien life by 2040. If there are a million, we'd discover alien life by 2028.

Nobody pretends the Drake Equation is the final word. Even its enthusiasts admit that it is, at best, a way to "organize our ignorance." But organized ignorance is a whole lot better than the disorganized kind; and it is, almost always, a starting point toward wisdom.
Methodology
Astronomers looking for alien signals have examined only a few thousand star systems so far. But as SETI Institute senior astronomer Seth Shostak has noted, the rate at which researchers are able to process the massive amounts of data that radio telescopes receive doubles approximately every 18 months to two years, meaning it grows by a factor of ten every six years or so.

The Milky Way has around 100 billion (10 ¹¹) star systems that could conceivably host intelligent life under our current assumptions. An estimate of 100,000 (10 ⁵) active civilizations in the galaxy would mean one per million star systems. At the exponential rate of growth in signal processing, researchers will have examined one million candidates by around 2034, bringing the odds of a discovery into the probable. Adding or removing a zero from the estimate of the number of civilizations out there merely adds or subtracts six years from the estimate, respectively, since that's how long it takes to expand our search proportionally. See you in 2040, aliens.

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human

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George and cooper

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The closest star to Earth are three stars in the Alpha Centauri system. The two main stars are Alpha Centauri A and Alpha Centauri B, which form a binary pair. They are an average of 4.3 light-years from Earth. The third star is Proxima Centauri. It is about 4.22 light-years from Earth and is the closest star other than the sun.

Alpha Centauri A and B orbit a common center of gravity every 80 years. The average distance between them is about 23 astronomical units (AU) - a little more than the distance between the sun and Uranus. Proxima Centauri is about one-fifth of a light-year or 13,000 AUs from the two other stars, a distance that makes some astronomers question whether it should be considered part of the same system.

Proxima Centauri may be passing through the system and will leave the vicinity in several million years, or it may be gravitationally bound to the binary pair. If it's bound, it has an orbital period around the other two of about 500,000 years.

Planet potential

Astronomers announced in August 2016 that they had detected an Earth-size planet orbiting Proxima Centauri. The newfound world, known as Proxima b, is about 1.3 times more massive than Earth, which suggests that the exoplanet is a rocky world, researchers said.

The planet is also in the star's habitable zone, that just-right range of distances where liquid water can exist. Proxima b lies just 4.7 million miles (7.5 million kilometers) from its host star and completes one orbit every 11.2 Earth-days. As a result, it's likely that the exoplanet is tidally locked, meaning it always shows the same face to its host star, just as the moon shows only one face (the near side) to Earth.

However, it's unclear just how habitable Proxima b is from today's telescopes. This means that astronomers need to run models and do comparative studies to better understand how habitable the planet might be. As a start, the planet needs a closer look for investigators to look for signs of an atmosphere. From there, the investigators can extrapolate if that atmosphere (if present) allows liquid water to flow on the surface. Even the surface temperature of the planet depends on the atmosphere, which would also play into habitability characteristics.

Because Proxima b is so close to a red dwarf, habitability problems are already coming to scientists' minds. For one thing, the planet is so close that it likely is tidally locked to the star, meaning that one side of the planet is always facing the star. This means one side of the planet would be very warm, while the opposite side would be very cold - unless winds could distribute the heat around the planet. That makes it hard for life to exist.

But the planet's close distance to the red dwarf presents other problems too. Red dwarfs are unstable stars, particularly when they are young - they have a lot of stellar activity and produce charged particles, which can produce intense radiation on nearby planets. Some of this radiation can strip molecules off the top of a planet's atmosphere and thin it over time, according to 2017 studies led by the NASA Goddard Space Flight Center in Greenbelt, Maryland.

Studies of red dwarf stars are ongoing to better understand the habitability of Proxima b. In November 2017, another planet in the habitable zone of a red dwarf was discovered that's almost as close to Earth as Proxima b is. Called Ross 128b, this planet orbits a red dwarf star that appears much quieter than that of Proxima b. The research team said that finding out more about its atmosphere will require a next-generation telescope such as the European Extremely Large Telescope, the Giant Magellan Telescope and the Thirty Meter Telescope that all are expected to bbe active in the 2020s. (The James Webb Space Telescope, set to launch in 2020, can't do the search itself since the planet does not transit across the face of its star.)

Binary stars

To the naked eye, the two main stars shine as one, making them the third brightest "star" in our night sky. The two separate stars can be seen through a small telescope; one of the finest binary stars that can be observed. Proxima Centauri is too faint to see unaided, and through a telescope it appears about four diameters of the full moon away from the other two. [ Infographic: The Nearest Stars to Earth]

By itself, Alpha Centauri A, also known as Rigel Kentaurus, is the third brightest star in the night sky; just a bit dimmer, by 0.02 of a magnitude, than Arcturus. It is a yellow star of the same type (G2) as the sun, and it is about 25 percent larger. Alpha Centauri B is an orange K2-type star, slightly smaller than the sun. Proxima Centauri is a red dwarf about seven times smaller than the sun, or one-and-a-half times bigger than Jupiter. All three stars are a bit older - 4.85 billion years old - than the sun, which is about 4.6 billion years old. [ Infographic: Alpha Centauri Stars & Planet Explained: Our Nearest Neighbors]

The system is in the Southern sky and is not visible to observers above the latitude of 29 degrees north - a line that passes near Houston, Texas, and Orlando, Fla. In the Southern Hemisphere, it's easy to find because the cross-piece of the Southern Cross (from Delta to Beta Crucis) points the way. Its right ascension is 14h 39m 41s and its declination is minus 60 degrees 50 minutes 7 seconds.

Additional reporting by Elizabeth Howell, Space.com contributor Correction: This article was updated on March 20, 2019 to include the correct distance between Alpha Centauri A and B.

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Alpha Centauri: Nearest Star System to the Sun

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The closest star to Earth are three stars in the Alpha Centauri system. The two main stars are Alpha Centauri A and Alpha Centauri B, which form a binary pair. They are an average of 4.3 light-years from Earth. The third star is Proxima Centauri.

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jamie and nathan
hi

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Sophie Davies

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Mercury

Mercury is the closest planet to the Sun. However, that doesn't mean it's too hot to have ice. In fact, Mercury has very deep craters that never see sunlight and are always cold.

NASA's Messenger mission saw bright spots at Mercury's north and south poles. Scientists think the bright spots might actually be water ice that is deep inside craters. This ice may have come to Mercury from comets and meteorites hitting the planet's surface.

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Mercury is the closest planet to the Sun. However, that doesn't mean it's too hot to have ice. In fact, Mercury has very deep craters that never see sunlight and are always cold. NASA's Messenger mission saw bright spots at Mercury's north and south poles.

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5,778 K

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Today's Wonder of the Day was inspired by John from AL. John Wonders, " is there life on other planets " Thanks for WONDERing with us, John!

Astronomers and other scientists constantly and explore space. One of the most intriguing questions they hope to answer one day is whether life exists on other planets. Despite a lot of in outer space , scientists have not yet been able to find of on any other planet other than Earth.

Earth is very hospitable , which makes living here easy. Earth has water, which living creatures need to survive.

Earth also has an atmosphere that is neither too hot, nor too cold. Its distance from the sun provides Earth's inhabitants with the proper amount of warmth, sunlight and energy.

Although there may be other planets that have some of Earth's hospitable features, so far scientists have not found any with all of the features they believe necessary to sustain life. Earth remains one of a kind!

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Hello? Is there anybody out there? Blast off with us as we search for new friends in outer space.

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BY SALIMAN

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By: Muzhda and Zara

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BY MANOA ######

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teawarua

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How Old Is the Moon? Scientists Say They Finally Know | Space

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What does it look like inside a black hole?

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What does it look like inside a black hole?

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Xavier did this!!

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cooper and George

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Time Travel Wormhole GIF by South Park - Find & Share on GIPHY

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Discover & share this South Park GIF with everyone you know. GIPHY is how you search, share, discover, and create GIFs.

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tewarua

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william and richo

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Most scientists agree that the Earth has pretty much always had its moon. Details of the moon's composition (in particular the "isotopic mixture" of heavier and lighter versions of various elements) are too similar to the Earth's for it to have been captured from somewhere remote. However, some compositional details differ enough to rule out the idea that the moon is simply a chunk of the Earth that broke loose.

The details of how the moon formed, and when, have long been debated. Now two new studies shed fresh light on the process - even pinning down a date.

For more than 30 years, the prevailing view of the formation of our moon has been the " giant impact hypothesis ". The precursors to the current four rock planets - Mercury, Venus, Earth and Mars - appear to have been dozens of smaller bodies known as "planetary embryos". According to the giant impact hypothesis, our moon formed as the result of the last of a series of "giant impact" mergers between planetary embryos that eventually formed the Earth. In this last collision, one embryo was nearly Earth-sized and the other approximately Mars-sized. The merged body resulting from this became the Earth. Debris flung out from the impact, most of which came from the rocky part of the smaller body, gathered in orbit to become the moon.

But how quickly did all this happen? Fortunately, the supernova explosion that is thought to have given the impetus for our local cloud of gas and dust to contract - and so form the sun and its planets - seeded the cloud with newly-formed isotopes of radioactive elements. As each decays to a stable isotope at a different rate, these provide an excellent series of clocks for timing the various events.

On this basis, the birth of the solar system is generally accepted to have occurred close to 4.57 billion years ago. Scientists have long debated how long after this Earth's moon-forming impact occurred. The "late school" favoured 150-200m years after, whereas the "early school" favoured a date less than about 100m years after the origin.

Now a new study suggests it was a very early date indeed, no more than 60m years after the solar system's birth. The team behind it, led by Melanie Barboni of the University of California, Los Angeles, analysed zircon crystals from samples of ancient lunar crust collected by Apollo 14. They argue that the ratio between two isotopes of the rare, zirconium-like element hafnium (Hf-176 and Hf-177 - the latter has one more neutron in the nucleus than the former) can be explained only if the magma ocean that covered the newly-formed moon had already solidified by 4.51 billion years ago.

Melanie Barboni via advances.sciencemag.org

This leaves, at most, only 60m years between the origin of the solar system and the solidification of the first lunar crust - the trace of which can be read in those zircon crystals.

NASA, AS14-68-9405

Set against the total age of the solar system, 60m years to go from a cloud of gas and dust around the infant sun to a fully-formed Earth with its own large moon might seem unfeasibly short. However, it is long enough - 60m years ago, Britain and Greenland were still joined together, with no intervening Atlantic ocean (and Iceland didn't exist at all). And bodies in space move a lot faster than Earth's slowly creeping continents.

A series of impacts instead?

Meanwhile, an unrelated study in Nature Geoscience, also just published, claims that the giant impact hypothesis is flawed. An Israeli team used sophisticated computer modelling, called "smoothed particle hydrodynamics", and concluded that it would be near impossible for such an event to produce a debris disc around the Earth with the necessary amount of angular momentum (rotational energy locked up in orbital motion and spin) to eventually form a stable moon.

Instead, they found that a more feasible way to form the moon is as the end result of a series of about 20 collisions by Mars-to-moon sized planetary embryos onto the body which later became the Earth. Each collision yielded a debris ring that would soon coalesce into a small moon. But tides would cause each successive moon to migrate outwards so that they would collide and merge with each other into the larger moon that we know today.

Raluca Rufu, et al. / Nature Geoscience

Are the two studies contradictory? I don't think so. If the multiple-impact model is correct, then the 60m-year limit to the formation of the moon after the birth of the solar system could still date the end, or nearly the end, of the sequence of moon mergers.

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Most scientists agree that the Earth has pretty much always had its moon. Details of the moon's composition (in particular the "isotopic mixture" of heavier and lighter versions of various elements) are too similar to the Earth's for it to have been captured from somewhere remote.

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by i hate veggtables

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An interactive visualization of the enormous objects in our universe. See how the Earth compares to the Sun, black holes and the Milky Way.

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How long does it take to make a black hole?

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How long does it take to make a black hole?

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Jane Farrelly

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A star can burn its hydrogen for millions or even billions of years. But when the party's over, black holes form in an instant. How long does it all take to happen.

Uh-oh! You're right next to a black hole that's starting to form.

In the J.J. Abrams Star Trek Universe, this ended up being a huge inconvenience for Spock as he tried to evade a ticked off lumpy forehead Romulan who'd made plenty of questionable life choices, drunk on Romulan ale and living above a tattoo parlor.

So, if you were piloting Spock's ship towards the singularity, do you have any hope of escaping before it gets to full power? Think quickly now. This not only has implications for science, but most importantly, for the entire Star Trek reboot! Or you know, we can just create a brand new timeline. Everybody's doing it. Retcon, ftw.

Most black holes come to be after a huge star explodes into a supernova. Usually, the force of gravity in a huge star is balanced by its radiation - the engine inside that sends out energy into space. But when the star runs out of fuel to burn, gravity quickly takes over and the star collapses. But how quickly? Ready your warp engines and hope for the best.

Here's the bad news - there's not much hope for Spock or his ship. A star's collapse happens in an instant, and the star's volume gets smaller and smaller. Your escape velocity - the energy you need to escape the star - will quickly exceed the speed of light.

You could argue there's a moment in time where you could escape. This isn't quite the spot to argue about Vulcan physiology, but I assume their reaction time is close to humans. It would happen faster than you could react, and you'd be boned.

But look at the bright side - maybe you'd get to discover a whole new universe. Unless of course Black holes just kill you, and aren't sweet magical portals for you and your space dragon which you can name Spock, in honor of your Vulcan friend who couldn't outrun a black hole.

Here we've been talking about what happens if a black hole suddenly appears beside you. The good news is, supernovae can be predicted. Not very precisely, but astronomers can say which stars are nearing the end of their lives.

Here's an example. In the constellation Orion, Betelgeuse the bright star on the right shoulder, is expected to go supernova sometime in the next few hundred thousand years.

That's plenty of time to get out of the way.

So: black holes are dangerous for your health, but at least there's lots of time to move out of the way if one looks threatening. Just don't go exploring too close!

If you were to fall through a black hole, what do you think would happen? Naw, just kidding, we all know you'd die. Why don't you tell us what your favorite black hole sci fi story is in the comments below!

And if you like what you see, come check out our Patreon page and find out how you can get these videos early while helping us bring you more great content!

Podcast (audio): Download (Duration: 3:08 - 2.9MB)

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Podcast (video): Download (Duration: 3:31 - 42.2MB)

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How Quickly Do Black Holes Form? - Universe Today

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A star can burn its hydrogen for millions or even billions of years. But when the party's over, black holes form in an instant. How long does it all take to happen. Uh-oh! You're right next to a black hole that's starting to form. In the J.J.

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Jane Farrelly

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Our Sun is a 4.5 billion-year-old yellow dwarf star - a hot glowing ball of hydrogen and helium - at the center of our solar system. It's about 93 million miles (150 million kilometers) from Earth and it's our solar system's only star. Without the Sun's energy, life as we know it could not exist on our home planet.

10 things

The part of the Sun we see from Earth - the part we call the surface - is the photosphere. The Sun doesn't actually have a solid surface because it's a ball of plasma.

The Sun would have been surrounded by a disk of gas and dust early in its history when the solar system was first forming 4.6 billion years ago. Some of that dust is still around today, in several dust rings that circle the Sun. They trace the orbits of planets, whose gravity tugs dust into place around the Sun.

As a star, the Sun doesn't have any moons, but the planets and their moons orbit the Sun.

Once material leaves the corona at supersonic speeds, it becomes the solar wind, which forms a huge magnetic "bubble" around the Sun, called the heliosphere. The heliosphere extends beyond the orbit of the planets in our solar system. Thus, Earth exists inside the Sun's atmosphere. Outside the heliosphere is interstellar space.

In one of the Sun's biggest mysteries, the corona is much hotter than the layers immediately below it. (Imagine walking away from a bonfire only to get warmer.) The source of coronal heating is a major unsolved puzzle in the study of the Sun.

Solar activity can release huge amounts of energy and particles, some of which impact us here on Earth. Much like weather on Earth, conditions in space - known as space weather - are always changing with the Sun's activity. "Space weather" can interfere with satellites, GPS, and radio communications. It also can cripple power grids, and corrode pipelines that carry oil and gas.

Another solar flare on March 13, 1989, caused geomagnetic storms that disrupted electric power transmission from the Hydro Québec generating station in Canada, plunging 6 million people into darkness for 9 hours. The 1989 flare also caused power surges that melted power transformers in New Jersey.

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From our vantage point on Earth, the Sun may appear like an unchanging source of light and heat in the sky. But the Sun is a dynamic star, constantly changing and sending energy out into space. The science of studying the Sun and its influence throughout the solar system is called heliophysics.

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Jane Farrelly

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Join us in Wonderopolis today as we go up, up, up to learn about what brings us down, down, down!