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Join our space trip to discover the secrets of distant planets!
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00:00Hey, I want to show you something.
00:02Let's take a little trip off of Earth
00:04and park our spacecraft somewhere near the Moon.
00:08We're now almost 240,000 miles away from our home planet.
00:13That's almost 100 times the width of the United States.
00:16Now we've brought a special set of tools with us.
00:18A giant hammer and an enormous chisel.
00:23Place the chisel at the Earth's north pole
00:24and strike its head with the hammer.
00:27The Earth cracks open like an eggshell
00:29and we see another planet.
00:32This is Theia.
00:34And it's hiding inside our planet like a yolk in an egg.
00:37If you want to find out how it got there,
00:39you'd need to travel back in time 4.5 billion years.
00:44This beautiful nebula
00:46is what will eventually become our solar system.
00:49Color dust and various space debris
00:51are slowly coming closer toward the common center.
00:54Over time, this jigsaw puzzle of debris
00:57becomes denser and heavier.
00:59The temperature inside the giant is rising.
01:02Soon, it gets so high
01:04that it'll trigger a nuclear chain reaction.
01:07One more second,
01:09and bam!
01:10There's an explosion so powerful
01:12that the shock waves travel far into deep space.
01:16When the dust clears a little,
01:17you can see that a bright light
01:19is still shining at the very center of the explosion.
01:22This newborn star is the Sun.
01:25It weighs as much as 333,000 Earths.
01:29If the Sun was a bucket,
01:30you'd need 1.3 million Earth-sized planets to fill it.
01:34But we're interested in that small object over there,
01:3893 million miles away from the Sun.
01:41This pile of rocks and hot lava is Earth.
01:44Right now, the planet is busy forming its core
01:46while the oceans of lava are gradually cooling down.
01:49But some millions of years later,
01:51after the Sun's birth,
01:52you notice another small object.
01:54Here comes Theia.
01:56This small planet was formed
01:58at about the same time as Earth.
01:59And right now,
02:00it's following a crazy,
02:02spiral trajectory at enormous speed.
02:05Scientists believe Theia was like a ball
02:07Jupiter and Venus played around with.
02:10Venus would pull Theia in one direction
02:12and then Jupiter would pull it right back.
02:15But what makes up 99.8% of the mass of the solar system
02:18is the Sun.
02:20It's what makes Theia move
02:22into almost the same orbit as Earth.
02:24So they inevitably come closer and closer to each other
02:27until they become next-door neighbors.
02:30We see that Theia is roughly the size of Mars,
02:33as wide as the Atlantic Ocean
02:35from New York to Portugal.
02:36At this point, the collision can't be avoided.
02:39Theia is traveling towards Earth
02:41at nearly 9,000 miles per hour.
02:43That's 11 times faster than the speed of sound.
02:46If this smaller planet would crash into Earth
02:48at a particular angle,
02:49Earth would most likely be torn apart,
02:51as well as Theia itself.
02:53The collision would cause a huge blast
02:55visible on other planets,
02:57even on a bright day.
02:59Nothing would be left
02:59but some burning dust and debris.
03:02Even if Theia only slightly grazes the Earth,
03:04it'll still knock out a sizable chunk.
03:07But the collision with Theia happens
03:08at a perfect 45-degree angle.
03:11It strikes the Earth at tremendous speed.
03:14The explosion literally vaporizes huge amounts of rock,
03:18and the shockwave sends the remaining debris
03:20into Earth's orbit.
03:22A huge crater is formed at the impact site,
03:24which soon gets filled in with boiling lava.
03:27The remnants of Theia
03:28and the ejected fragments of Earth
03:30begin to orbit our planet.
03:32According to one theory,
03:34these fragments actually form two moons.
03:36At first, they travel together,
03:38but one day they get too close to each other
03:41and collide,
03:42forming one large space body.
03:44The other theory claims
03:45that all the loose shards
03:47get pulled in by the remnants of Theia,
03:49and that sometime after that,
03:51they form the moon,
03:52as we know it today.
03:53At this point in the past, though,
03:55it's just red-hot rock and lava.
03:57The collision at this angle
03:58slightly tilts our planet
04:00and accelerates its rotation.
04:02It's because of Theia
04:03that we have different seasons
04:05and 24 hours in a day.
04:07Now, Earth also has these things
04:09called lithospheric plates.
04:11These are enormous solid landmasses
04:13that make up the crust of our planet.
04:15After the collision with Theia,
04:17they start to break and crack.
04:19It causes carbon,
04:20a primary component of all known life on Earth,
04:23to start moving all over our planet.
04:25So, Earth gains a kind of metabolism.
04:28After a few hundred million years,
04:31the first living creatures
04:31start to appear on our planet.
04:33Over the next nearly 4 billion years,
04:36simple single-cell organisms evolve
04:38into the kinds of complex life
04:39you see today.
04:41According to scientists,
04:42a collision like we had with Theia
04:43is a very rare event.
04:45The probability that somewhere out there
04:47there's a planet like ours
04:48that has survived the same catastrophe
04:50is even rarer still.
04:52This may be the reason
04:54why we have yet to find
04:55other traces of other civilizations
04:57out there in space.
04:59Meanwhile,
05:00the remains of Theia
05:01are still here on Earth.
05:03Of course,
05:03it doesn't look like an actual
05:04entire planet
05:05stuck inside our own.
05:07Most of the fragments
05:08have melted and blended
05:09into the Earth's crust.
05:11If you take the top layer
05:12off our planet,
05:13you'll see two huge lava blobs
05:15the size of large continents.
05:17They're right below Africa
05:19and the Pacific Ocean.
05:20Presumably,
05:21these are the remains of Theia.
05:23They didn't mix with the Earth's mantle
05:25because of different densities.
05:27It's like mixing water and oil
05:29in a glass.
05:30The oil will always float up
05:32over the water
05:33and create an even layer
05:34on top of it.
05:35But if you raise these lava patches
05:37up to the surface,
05:38they'd be a hundred times higher
05:40than Mount Everest.
05:42Other remains of Theia
05:43might be on the Moon.
05:45The Apollo space missions
05:47brought back many soil samples
05:48for analysis,
05:49which led scientists to conclude
05:50that the Moon is very similar
05:51to the Earth in structure.
05:54Someday in the future,
05:55people could drill deep down
05:57and take samples
05:58of the Moon's crust.
05:59Then they'd analyze
06:01the blobs from Earth.
06:02And if their structure matched,
06:04it would be undeniable proof
06:05that Theia did hit Earth
06:074.5 billion years ago
06:09and gave us the Moon.
06:10But for the time being,
06:12Theia remains an unsolved mystery.
06:15Scientists are still not sure
06:16that the planet actually existed.
06:18The whole idea does perfectly fit
06:20the model of the Moon's creation,
06:22but it's also possible
06:23that this incredible collision
06:25may have never happened.
06:27Now, let's travel
06:2841 light years away from Earth
06:30to the planet 55 Cancri e.
06:34It's about twice the size of Earth
06:36and eight times heavier.
06:38Let's take out our giant hammer again
06:39and use it to hit the chisel.
06:41The planet cracks
06:43and you see it's a giant diamond.
06:45The temperature on this planet
06:47is tens of times higher
06:48than on Earth
06:49and its soil is rich in carbon.
06:52The heat puts a lot of pressure
06:53on this carbon
06:54and the structure changes.
06:56First, it turns into graphite,
06:59but then add just a bit more pressure
07:01and the graphite turns to diamond.
07:04On Earth, diamonds form at depths
07:0660 miles below sea level,
07:08where the pressure is 50,000 times greater
07:10than that on the surface.
07:11And the temperature there
07:13averages over 1,000 degrees,
07:15which is as hot as fire.
07:17Diamonds are often ejected closer
07:18to the surface in volcanic eruptions,
07:20but still, people mostly have to dig
07:22mines 1,500 feet deep
07:25to find these beautiful gems.
07:28Currently, the Golden Jubilee Diamond
07:30is the biggest cut
07:31and faceted diamond on Earth.
07:33It weighs as much as a chocolate bar
07:35and is the size of a hamster.
07:37Its price is about $12 million.
07:40Now, imagine a diamond
07:42the size of an entire planet!
07:45Now, let's fly back to our solar system.
07:48Our destination now
07:49is Jupiter's moon Europa.
07:50It's as wide as the distance
07:52between Seattle and Houston,
07:54and its mass is less than 1%
07:56of the mass of Earth.
07:57Its surface is enclosed in an icy crust
07:59that's about 19 miles thick.
08:02Europa is completely covered in water.
08:04It's freezing here,
08:05three times colder than that
08:06of the North Pole and Earth.
08:07The water turns to ice almost instantly.
08:10But the ocean beneath the surface
08:12is still liquid.
08:14Europa has a gravitational relationship
08:16with Jupiter,
08:17just like the moon with the Earth.
08:19This creates tidal forces
08:20that heat Europa's core,
08:22which then melts the ice around it.
08:25The result is a huge ocean,
08:27two or three times larger
08:28than that of Earth's oceans combined.
08:31Scientists believe that water
08:32is one of the essential ingredients for life.
08:33This means that life may exist on Europa.
08:37There could be thermal springs,
08:39just like at the bottom of our oceans,
08:41though the water there
08:42is probably much warmer.
08:44And even though the pressure
08:45and temperature in such places
08:46are likely to be extreme,
08:48simple bacteria could live there.
08:50Europa is almost the same age as Earth,
08:53so there has been enough time
08:55for living organisms
08:56to appear and evolve.
08:58Who knows?
08:59Maybe some advanced civilization
09:00is already blooming
09:02under this crust of ice.
09:04They might be building big cities
09:05and dreaming of conquering space.
09:08But for now,
09:09all we can do is speculate.
09:11And maybe someday send a probe
09:13to Europa to find out
09:14if life is possible there.
09:31So check this out.
09:33Astronomers have discovered
09:34an exoplanet
09:36they're calling Super Saturn.
09:38It's got rings over an AU wide.
09:41An AU is the astronomical unit,
09:43the distance between the Sun to the Earth.
09:45That's an incredibly huge ring system,
09:48hence its name.
09:50Super Saturn is being called
09:52Mamajek's object
09:53after the astronomer
09:54who led the team
09:55to whom we owe the discovery.
09:57Professor Eric Mamajek
09:59of Rochester University in New York
10:01found Super Saturn
10:02while scouring through data
10:04downloaded from
10:05wide-angle transit observations.
10:08WASP is the acronym
10:09for Wide-Angle Search for Exoplanets.
10:12It's an ingenious project
10:14developed in the year 2000
10:16by astronomers
10:16at Queen's University
10:18in Belfast, Northern Ireland
10:19and St. Andrew's University
10:21in Scotland.
10:22Using four telescopes,
10:24the CCD video cameras
10:26on the scopes
10:26record the slight dimming
10:28of starlight
10:28caused by objects
10:30passing in front of stars.
10:31This is called
10:32the transit method
10:33of exoplanet detection.
10:35So, for example,
10:37the planet Venus
10:37transits across our view
10:39of the Sun
10:40every couple hundred years.
10:41A black dot
10:43the silhouette of Venus
10:44is visible
10:45crossing in front of the Sun
10:46as Venus passes
10:47between our line of sight
10:49and the Sun.
10:50This tiny eclipse
10:52causes the amount
10:53of sunlight
10:53coming to Earth
10:54to be reduced
10:55by a minuscule amount
10:57also known as teeny tiny.
10:59The same is true
11:00for all the stars
11:01in the Milky Way
11:02that have planets
11:03going around them.
11:05Exoplanetary transits
11:06in front of stars
11:07must be in direct
11:09line of sight
11:09with Earth
11:10for the starlight
11:11to be dim.
11:12Such transits
11:13do not occur
11:14very often.
11:15That's why
11:15thousands of stars
11:16must be looked at
11:17simultaneously
11:18for as long
11:19of a duration
11:20as possible
11:21between four
11:22and eight hours
11:23a night.
11:24WASP was created
11:25to stare continuously
11:26at as wide
11:27of a range
11:28of stars as possible.
11:29Maybe one of them
11:30would show
11:31an exoplanet transit.
11:33That translates
11:34into a lot
11:35of data
11:36being produced
11:36about 40 gigabytes
11:38per viewing session.
11:39Computer scientists
11:40at Leicester University
11:42in England
11:42developed a computer
11:44program
11:44to store the data
11:45and generate
11:46photometric graphs
11:47of the light intensity
11:48of each star.
11:50Open University,
11:51also in England,
11:52joined the WASP project,
11:54took this data
11:54and made it available
11:56for research
11:56by astronomers worldwide.
11:58The graphs
11:59of the intensity
12:00of starlight
12:01show that changes
12:02in its brightness
12:03are called light curves.
12:04These graphs
12:05have two axes.
12:06One is in the
12:07timeline axis,
12:09the other one
12:09is the intensity
12:10of light.
12:11As the object,
12:12considered an exoplanet,
12:14though it could also
12:15be a brown dwarf star,
12:16crosses in front
12:17of the star,
12:18the timeline axis
12:19keeps track
12:20of how swiftly
12:21it is moving.
12:22It tells us
12:22how close
12:23the object is
12:24to the star,
12:25while the brightness axis
12:26keeps track
12:27of how much
12:27the starlight dims.
12:29This way,
12:30we can find out
12:30how large
12:31the object is.
12:33Now, obviously,
12:34big objects
12:35will dim the light
12:36more and be easier
12:37to detect.
12:38At present,
12:39Earth-based equipment
12:40is not sensitive
12:41enough to measure
12:42the dimming
12:42caused by planets
12:43as small as Earth.
12:45Neptune's size
12:46and larger ones
12:47are the limit
12:48for WASP.
12:49However,
12:50the James Webb Space Telescope,
12:51which is now in operation,
12:53has a much greater sensitivity
12:55and will be able
12:56to resolve
12:56the transits
12:57of Earth-sized exoplanets.
13:00Now, I know
13:01you want me
13:02to get to Super Saturn,
13:03but there's something else
13:04you should be familiar with
13:05before we get there.
13:07If the exoplanet
13:08has an atmosphere,
13:09or, in the case
13:11of Super Saturn,
13:12a ring system,
13:13the starlight
13:14from the star
13:15the planet
13:15is transiting
13:16will shine
13:17through the atmosphere
13:18or ring system,
13:19and that
13:20can be detected too.
13:22The light curve
13:22will show less dimming
13:24in the photometric data,
13:25because not all
13:26the starlight
13:27is being blocked.
13:28Some light
13:29is still getting
13:29through the atmosphere
13:30or rings.
13:31This is important
13:32because it gives astronomers
13:34a reading
13:35of the atmosphere.
13:36The James Webb Space Telescope
13:38is fitted
13:39with spectroscopes
13:40that can determine
13:41the gas content
13:42of the transiting
13:43exoplanet atmospheres
13:44– oxygen,
13:45methane,
13:46carbon, etc.
13:47The WASP project
13:48has been really
13:49catching on.
13:50There's a Super WASP project
13:52now consisting of
13:53WASP north
13:54and a WASP south.
13:56One looks at
13:57the sky above
13:58the northern hemisphere,
13:59the other looks at
14:00the sky above
14:01the southern hemisphere.
14:02There's also
14:03a next-generation
14:04transit survey
14:05– NGTS –
14:06based on the WASP project.
14:08It's automated,
14:09so astronomers
14:10don't have to
14:11stay up all night
14:12sipping coffee,
14:13but they can
14:13if they want to.
14:15Located at
14:16the European
14:17Southern Observatory
14:18in the Atacama Desert
14:19in Chile,
14:20the NGTS
14:21scans millions
14:22of stars
14:23and has discovered
14:24over a hundred
14:25exoplanets
14:26down to a size
14:27as small as
14:28three times
14:28the size of Earth.
14:30NGTS has started
14:31a Planet Hunters Club
14:33on social media.
14:34Citizen scientists
14:35can search the
14:36online database
14:37of light curves
14:38and perhaps
14:39discover your
14:40very own
14:40exoplanet.
14:41What had been
14:42a strictly
14:43British effort
14:44started by
14:44one or two
14:45astronomers
14:45is now
14:46a worldwide
14:47phenomenon.
14:48With the ability
14:49to read the
14:50spectroscopic
14:51signatures
14:51of atmospheric
14:52gases
14:53during exoplanet
14:54transits,
14:55a new idea
14:56emerged,
14:57techno-signatures,
14:58that is
14:59specifically
15:00identifying gases
15:01in exoplanet
15:02atmospheres
15:03that are produced
15:04by civilizations.
15:05The James Webb
15:06Space Telescope
15:07can do this.
15:08Gases from
15:09pollution,
15:10such as
15:10chlorofluorocarbon
15:12CFCs,
15:13can be seen
15:13spectroscopically
15:14if present.
15:16Tritium
15:16from fusion
15:17reactions,
15:18if they have them,
15:18can also be detected,
15:20along with heat
15:21patterns from
15:21cities on
15:22the planet's
15:23surfaces.
15:24Techno-signatures
15:24is a recent
15:25concept that
15:26originated after
15:27the WASP
15:28project started.
15:29Who knows
15:30what it will
15:30turn up?
15:32Now,
15:33let's get back
15:33to Super Saturn.
15:35The star
15:36that Super Saturn
15:36orbits is
15:38J1407,
15:39a small,
15:40dim,
15:41sun-like
15:41pre-main
15:42sequence star
15:43of the 13th
15:43magnitude.
15:44Huh?
15:45Well,
15:45the human eye
15:46can only see
15:47stars to about
15:48the 6th magnitude,
15:49and each
15:50magnitude is
15:50two-and-a-half
15:51times dimmer
15:52than the
15:52previous one.
15:53So,
15:54it's not an
15:54exceptional star,
15:56just another
15:56telescopic star
15:57out there
15:58in the Scorpio-Centaur
15:59region of the
16:00night sky.
16:02J1407 is a
16:03young star
16:04that hasn't yet
16:04settled into its
16:05stable,
16:06long-duration
16:07phase.
16:07This is important
16:08because Super
16:09Saturn,
16:10officially
16:11J1407b,
16:12is showing signs
16:13of having a
16:14ring system
16:15in an early
16:16stage of
16:16development.
16:17Super
16:18Saturn's
16:18light curve
16:19was tucked
16:19away in the
16:20mountain of
16:21data from
16:21the Super
16:22Wasp project.
16:23Professor Eric
16:24Mamajak and
16:25his associate
16:25Matthew Kinworthy
16:27of Leicester
16:27University studied
16:29the data thoroughly
16:30and produced a
16:30detailed report
16:31on it.
16:32Knowledge depends
16:33on good data.
16:34The horizontal
16:35axis of
16:37J1407b's
16:38light curve,
16:39the time
16:39axis,
16:40is what's
16:40causing all
16:41the hubbub.
16:42It took
16:43Super
16:43Saturn weeks
16:44to transit
16:45across in
16:46front of its
16:46parent star,
16:4756 days to
16:49be exact.
16:50Planetary ring
16:51systems that
16:51we are familiar
16:52with in our
16:53solar system
16:54orbit right
16:55around the
16:55equators of
16:56the gas giant
16:57planets and
16:58are very thin,
16:59from only a
16:59few meters thick
17:00down to a
17:01few centimeters.
17:02In a
17:03telescope,
17:04Saturn's rings
17:04will seem to
17:05disappear when
17:06the planet is
17:07at zero
17:07inclination toward
17:08Earth.
17:09Saturn must be
17:10inclined at an
17:11angle in relation
17:12to Earth to
17:13see Saturn's
17:14beautiful ring
17:14system.
17:15It's something
17:16everyone should
17:16make a point of
17:17seeing, Saturn in
17:18a telescope.
17:19If Super
17:20Saturn's rings
17:21blocked most of
17:22the light from
17:23J1407 for
17:2456 days, it
17:26means that the
17:27planet had to
17:28be orbiting at
17:29a steep inclination
17:30to its star.
17:31If it were at
17:32zero inclination,
17:33we wouldn't see
17:34the rings blocking
17:35any line.
17:36Therefore, the
17:37orbital time could
17:38be determined,
17:3910 years minimum
17:40to 200 years if
17:42the orbit is
17:43highly elliptical.
17:45The super
17:46planet itself is
17:47calculated to be
17:4824 times the
17:49mass of Jupiter,
17:50which means that
17:51if it is gaseous,
17:53it could be a
17:54brown dwarf star.
17:55Super Saturn
17:56appears to have a
17:57Mars-sized object
17:58orbiting around it
17:59because there is a
18:00huge gap in the
18:01rings that was most
18:02probably cleared out
18:04by a large object.
18:05The Cassini division
18:06in the rings of
18:07Saturn is where the
18:08moon Mimas has
18:10cleared out a path
18:11through Saturn's
18:11rings.
18:12The light curve of
18:13super Saturn has
18:14only been observed
18:15once.
18:16All the exoplanet
18:17detection systems are
18:19keeping an eye out
18:19for it to come back
18:21around J1407.
18:22No one knows when
18:24that will occur.
18:25Some astronomers
18:26have suggested that
18:28J1407b is a brown
18:29dwarf star system in
18:30itself, merely passing
18:32in front of, but not
18:33connected to, star
18:36J1407.
18:36An orbital reappearance
18:38of super Saturn would
18:39disprove that
18:40conjecture.
18:41The center region of
18:43super Saturn blocked
18:44out all the light from
18:45its primary star.
18:46This is what indicates
18:48that the ring system is
18:49new and in an early
18:50developmental phase.
18:52Over time, the very
18:54dense ring mass close
18:55to the planet is
18:56expected to thin as
18:58all this matter gets
18:59absorbed into the
19:00planet or ejected into
19:01space.
19:02This is what has
19:03happened with our
19:04solar system's gas
19:05giant planets.
19:06The Momajek object is
19:08a shocker.
19:09Never before or since
19:10has a light curve been
19:12detected like super
19:13Saturn's.
19:14Super Saturn has added
19:15a new chapter to our
19:17understanding of the
19:18formation of ring
19:19systems.
19:19So, here's to you
19:21super Saturn.
19:22Hope to see you again
19:23soon.
19:25There's only one star
19:26in our solar system,
19:28the Sun.
19:29And all the planets
19:30orbit this star.
19:32But, there are also
19:33systems where a planet
19:34orbits two suns.
19:36For example, Kepler-16b.
19:38It's an inhospitable
19:40and cold place, made
19:41of half rock, half gas.
19:43But, the coolest thing
19:45there is that if you
19:46visited this planet,
19:47you'd see two sunsets
19:49and have two shadows.
19:50But astronomers seem
19:52to have found something
19:52rarer and more bizarre.
19:54There might be a planet
19:55that orbits three stars
19:57at once.
19:58The GW Orionis star
20:00system is around
20:011,300 light-years away
20:03from our planet.
20:04It's composed of
20:05three orange rings.
20:07They're made of dust
20:08and nested inside
20:09one another.
20:10In the center of this
20:11system, you can see
20:12three stars.
20:13Two of these stars
20:14are binary.
20:15It means they orbit
20:16each other.
20:17The third star
20:18revolves around them.
20:20Scientists have found
20:21out that the three rings
20:22are misaligned.
20:23The innermost ring
20:25swings widely in its orbit.
20:26And the outermost ring
20:28has a tilt of 38 degrees.
20:30So, astronomers came up
20:32with two theories.
20:33The first theory
20:34says the break in these rings
20:36occurred because
20:37three suns created torque
20:39at the center
20:39of the entire system.
20:41Torque is a gravitational force
20:43that always acts
20:44toward the center.
20:45But sometime later,
20:46this theory was written off.
20:48There wasn't enough turbulence
20:49in these rings
20:50for this theory to work.
20:52The second theory
20:53claimed that this phenomenon
20:54could be happening
20:55because a planet formed
20:57inside one of these rings.
20:59A young planet
21:00could affect
21:00the gravitational balance
21:02of the three ring system
21:03and be the reason
21:04they were spread
21:05so far apart.
21:06There's a specific gap
21:08in the dust cloud.
21:09Based on its size,
21:10the planet we're talking about
21:12must be a large gas giant
21:13the size of our Jupiter.
21:16All space objects
21:17have been formed
21:18thanks to gravity
21:19pulling matter together.
21:20If there's even
21:21the slightest rotation
21:22at the beginning,
21:23the spin rate
21:24increases with time,
21:26especially when an object
21:27starts collapsing.
21:28That's why all space objects
21:30rotate,
21:31including dust particles
21:32and even black holes.
21:34Black holes lose their mass
21:36because of a thing
21:36called hawking radiation.
21:38Their event horizons
21:40are becoming smaller,
21:41but this process
21:42is very, very slow.
21:44A black hole's event horizon
21:46is a point of no return.
21:47It's like a boundary
21:49that surrounds a black hole.
21:50And nothing,
21:51including light
21:52and radiation,
21:53can escape
21:54once it crosses
21:55this boundary.
21:56The average black hole
21:57would need billions of times
21:59the age of our universe
22:00to disappear completely.
22:02Our home Milky Way galaxy
22:04might also contain
22:05a supermassive black hole,
22:07but we're in no danger.
22:09One of the closest
22:10large black holes,
22:12V4647 Sagittarii,
22:14is most likely
22:1520,000 light years away.
22:17It's safe to observe
22:18the effects black holes
22:19create from a distance.
22:21Problems start
22:22when you get too close
22:23because of their
22:24mind-boggling
22:25gravitational force.
22:27Galaxies can consume
22:28one another,
22:29which is one of the ways
22:30how they evolve over time.
22:32Our closest neighbor
22:33is called Andromeda,
22:34and it's currently munching
22:36on one of its
22:37satellite galaxies.
22:39In the past,
22:40Andromeda ate
22:41at least two others.
22:43Plenty of star clusters
22:44are scattered
22:45all over this galaxy.
22:46Andromeda must have
22:48stolen these stars
22:48from other galaxies.
22:50Scientists have finally
22:51managed to identify
22:52those stars.
22:53They have tracked them
22:54back to galaxy mergers
22:56that happened
22:56billions of years ago.
22:58Ten billion years ago,
23:00our home galaxy
23:01also went through
23:02a collision.
23:03That's why now,
23:04its halo isn't like
23:05the ones other
23:06spiral galaxies have.
23:07Scientists first thought
23:08it was several
23:09small collisions,
23:10but then they realized
23:12that most of these
23:13space objects
23:13in the Milky Way
23:14came from a single source.
23:16It was another galaxy,
23:18Enceladus,
23:19that the Milky Way
23:20collided with.
23:21The Milky Way
23:22and Andromeda galaxy
23:23might collide,
23:25but it's unlikely
23:26to happen
23:26in the next
23:274.5 billion years.
23:30Neutrinos
23:30are electrically
23:31neutral particles
23:32that are so powerful
23:33that they can go through
23:34miles and miles
23:35of lead,
23:36and nothing will stop them.
23:38Some of them
23:39are passing through
23:39your body
23:40as you're watching this.
23:42Neutrinos get formed
23:43both in the nuclear reactions
23:44inside alive stars
23:46and in the supernova explosions
23:48when stars go out.
23:49These particles
23:50are nearly massless.
23:52They need less than
23:533 seconds
23:54to get to the surface
23:54of the sun.
23:55And then,
23:56they can reach our planet
23:57in only 8 minutes.
23:59There's a planet,
24:00TOI-1231b,
24:03around 90 light-years
24:04away from Earth.
24:05It's similar
24:06to our Neptune.
24:07It's a gas giant,
24:08but the most interesting thing
24:10is that this planet
24:11is likely to be rich
24:12in atmosphere.
24:14The planet is over
24:153.5 times as large as Earth
24:17and a bit warmer
24:18than we're used to,
24:19134 degrees Fahrenheit.
24:21It orbits a red dwarf star,
24:23way smaller than our sun.
24:25But this star
24:26is also much older.
24:27One year on the planet
24:28is only 24 Earth days long.
24:31Even though the planet
24:32is close to its parent star,
24:34it remains relatively cold.
24:36That's because its star
24:37is on the cooler side, too.
24:39Astronomers think
24:40they've seen clouds
24:41in the atmosphere
24:42of this mysterious planet.
24:43And maybe,
24:44they're even made of water.
24:46This star and planet system
24:48is moving away
24:49from Earth pretty fast.
24:51That's why scientists
24:52easily detected
24:53hydrogen atoms
24:54that were escaping
24:55from the planet's atmosphere.
24:57Yep,
24:57that means the planet
24:58may even have a tail.
25:00A hypothetical white hole
25:02is a bizarre space object
25:04that is the opposite
25:05of a black hole.
25:06It's intensely bright
25:07and was first mentioned
25:09by Einstein
25:09in his theory of gravity.
25:11Most often,
25:12scientists talk about
25:13white holes
25:14in the context
25:15of wormholes.
25:16There's a theory
25:17that a black hole
25:18is like some sort
25:19of entry point
25:20to a tunnel
25:21that takes you
25:22through space and time.
25:23In this case,
25:24a white hole
25:25might be an exit
25:26located somewhere else
25:28in the universe.
25:29On the other hand,
25:30white holes
25:31don't necessarily
25:32need to be exits
25:33from wormholes.
25:34They could also be
25:35a slow-motion replay
25:36of how original
25:38black holes were formed.
25:39So,
25:40the formation
25:41of a black hole
25:42starts with an old
25:43massive star.
25:44After it collapses
25:45under its own weight,
25:46it usually turns
25:47into a black hole.
25:48But sometimes,
25:50quantum processes
25:51don't turn a star
25:52into a black hole.
25:53Instead,
25:54they make
25:55a white hole
25:55that starts spewing
25:57out the matter
25:57of the original star again.
25:59But so far,
26:00this is just a theory.
26:02Some planets,
26:03like Mars and Venus,
26:04have pretty intense weather
26:06with powerful storms.
26:07And now,
26:08an equally strong
26:09space hurricane
26:10might have come
26:11to Earth.
26:12It was a swirling
26:13mass of air
26:14about 620 miles wide.
26:16Satellites spotted
26:18the hurricane
26:18hundreds of miles
26:19above the North Pole,
26:20somewhere in the
26:21Earth's upper atmosphere.
26:22The hurricane
26:23was raining
26:24not water,
26:25but electrons.
26:26It lasted
26:27almost eight hours
26:28before it finally
26:29broke down.
26:30It was spinning
26:31in a counterclockwise
26:32direction.
26:34It's possible
26:35there are oceans
26:35hidden under the surface
26:37of the moons
26:37surrounding Uranus.
26:39Scientists have also
26:40been investigating
26:41the oceans
26:41on Jupiter's moon
26:42Europa
26:43and Saturn's moon
26:44Enceladus.
26:45These oceans
26:46are hidden below
26:47the moon's icy crusts.
26:49Uranus has 27 moons.
26:52Five of them
26:52are especially big.
26:54Those are
26:55Umbriel,
26:55Titania,
26:56Oberon,
26:57Miranda,
26:58and Ariel.
26:59Back in the 1980s,
27:01when people sent
27:02Voyager 2
27:03to get us some images
27:04of these five moons,
27:05scientists found out
27:06that they had
27:07lots of craters
27:08and were made up
27:09of ice and rock.
27:10Pictures astronomers
27:11got then
27:12also showed signs
27:13of liquid water.
27:14It was erupting
27:16from the moon's depths
27:17and freezing
27:17on the surface.
27:18One of the most
27:19plausible explanations
27:20was the oceans
27:21under the surface.
27:23As a moon moves
27:24around a planet,
27:25the magnetic field
27:26of that planet
27:27tugs at it.
27:27That is how
27:28the moon stays
27:29in its orbit.
27:30This tug generates
27:31an electrical current
27:32that transforms
27:33into a magnetic field.
27:35Such a magnetic field
27:36is called induced,
27:38and subsurface oceans
27:40might be the reason
27:41why this induced field
27:42can be produced.
27:44Saturn is well known
27:45for its famous rings,
27:46but Neptune,
27:48Uranus,
27:48and Jupiter
27:49also have rings.
27:50At the same time,
27:52Saturn has something
27:53really special
27:54we've never seen
27:55on any other planet.
27:56It's this huge
27:57hexagon storm
27:58moving around
27:59the planet's
28:00north pole.
28:01Each of its sides
28:02is almost 7,500 miles long.
28:05That's an area
28:06so great,
28:07we could place
28:07almost four Earths inside.
28:10According to thermal images,
28:11this hexagonal cloud pattern
28:13goes down into
28:14Saturn's atmosphere
28:15for around 60 miles.
28:17The planet is hiding
28:18behind thick clouds,
28:19and sunlight
28:20can't get through them.
28:21That's why astronomers
28:22can't see
28:23what exactly
28:24is going on there.
28:25But there are theories.
28:27Saturn is a gas giant.
28:28When gas deep inside
28:30the planet gets heated,
28:31it strays further out.
28:33Huge amounts of energy
28:34are released
28:35along with that gas,
28:36which makes it rise,
28:38expand,
28:38and lose density.
28:40The same processes
28:41cause hurricanes
28:42and tornadoes
28:43on our planet.
28:44On Saturn,
28:45whirling gases
28:46come out of
28:47a high-pressure zone
28:48located within
28:49Saturn's outer layers,
28:50and these gases
28:51trigger a powerful storm
28:53of such an unusual shape.
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