The North Star, Polaris, is acting a little strange lately, and scientists are scratching their heads about it. Normally, it’s a pretty stable star that’s been our guiding light for centuries, but recent observations show it’s dimming and brightening in unexpected ways. This could mean something big is happening inside the star, like changes in its core or fusion process. It’s a big deal because Polaris has been a key reference point for navigation and astronomy for ages. Studying its weird behavior might teach us more about how stars like it evolve. It’s like the North Star is trying to tell us a cosmic secret! Credit:
Carved Box: Farm, CC BY-SA 2.5 https://creativecommons.org/licenses/by-sa/2.5/, https://commons.wikimedia.org/wiki/File:Carved_Box_with_Figure_Design.jpg?uselang=ru
CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0/:
Till Credner:
UrsaMinor, https://commons.wikimedia.org/wiki/File:UrsaMinorCC.jpg
LyraCC, https://commons.wikimedia.org/wiki/File:LyraCC.jpg
CC BY 4.0 https://creativecommons.org/licenses/by/4.0/:
Star Life Cycle Chart: R.N. Bailey, https://commons.wikimedia.org/wiki/File:Star_Life_Cycle_Chart.jpg
Diagram of the life of Sun-like stars: ESO/S. Steinhöfel, https://commons.wikimedia.org/wiki/File:Diagram_of_the_life_of_Sun-like_stars.jpg
Ishtar gate: Radomir Vrbovsky, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0/, https://commons.wikimedia.org/wiki/File:Ishtar_gate_in_Pergamon_museum_in_Berlin..jpg
NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-Hubble/Europe Collaboration; Acknowledgment: H. Bond (STScI and Penn State University)
NASA/ESA/HST, G. Bacon (STScI)
NASA/HST
NASA/Goddard Space Flight Center
NASA, Mysid
NASA/JPL-Caltech/University of Arizona
Animation is created by Bright Side.
#brightside
----------------------------------------------------------------------------------------
Music from TheSoul Sound: https://thesoul-sound.com/
Listen to Bright Side on:
Spotify - https://open.spotify.com/show/0hUkPxD34jRLrMrJux4VxV
Apple Podcast - https://podcasts.apple.com/podcast/idhttps-podcasts-apple-com-podcast-bright-side/id1554898078
----------------------------------------------------------------------------------------
Our Social Media:
Facebook - https://www.facebook.com/brightside/
Instagram - https://www.instagram.com/brightside.official/
Tik Tok - https://www.tiktok.com/@brightside.official?lang=en
Snapchat - https://www.snapchat.com/p/c6a1e38a-bff1-4a40-9731-2c8234ccb19f/1866144599336960
Stock materials (photos, footages and other):
https://www.depositphotos.com
https://www.shutterstock.com
https://www.eastnews.ru
----------------------------------------------------------------------------------------
For more videos and articles visit: http://www.brightside.me
Carved Box: Farm, CC BY-SA 2.5 https://creativecommons.org/licenses/by-sa/2.5/, https://commons.wikimedia.org/wiki/File:Carved_Box_with_Figure_Design.jpg?uselang=ru
CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0/:
Till Credner:
UrsaMinor, https://commons.wikimedia.org/wiki/File:UrsaMinorCC.jpg
LyraCC, https://commons.wikimedia.org/wiki/File:LyraCC.jpg
CC BY 4.0 https://creativecommons.org/licenses/by/4.0/:
Star Life Cycle Chart: R.N. Bailey, https://commons.wikimedia.org/wiki/File:Star_Life_Cycle_Chart.jpg
Diagram of the life of Sun-like stars: ESO/S. Steinhöfel, https://commons.wikimedia.org/wiki/File:Diagram_of_the_life_of_Sun-like_stars.jpg
Ishtar gate: Radomir Vrbovsky, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0/, https://commons.wikimedia.org/wiki/File:Ishtar_gate_in_Pergamon_museum_in_Berlin..jpg
NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-Hubble/Europe Collaboration; Acknowledgment: H. Bond (STScI and Penn State University)
NASA/ESA/HST, G. Bacon (STScI)
NASA/HST
NASA/Goddard Space Flight Center
NASA, Mysid
NASA/JPL-Caltech/University of Arizona
Animation is created by Bright Side.
#brightside
----------------------------------------------------------------------------------------
Music from TheSoul Sound: https://thesoul-sound.com/
Listen to Bright Side on:
Spotify - https://open.spotify.com/show/0hUkPxD34jRLrMrJux4VxV
Apple Podcast - https://podcasts.apple.com/podcast/idhttps-podcasts-apple-com-podcast-bright-side/id1554898078
----------------------------------------------------------------------------------------
Our Social Media:
Facebook - https://www.facebook.com/brightside/
Instagram - https://www.instagram.com/brightside.official/
Tik Tok - https://www.tiktok.com/@brightside.official?lang=en
Snapchat - https://www.snapchat.com/p/c6a1e38a-bff1-4a40-9731-2c8234ccb19f/1866144599336960
Stock materials (photos, footages and other):
https://www.depositphotos.com
https://www.shutterstock.com
https://www.eastnews.ru
----------------------------------------------------------------------------------------
For more videos and articles visit: http://www.brightside.me
Category
😹
FunTranscript
00:00Locating the North Star is quite easy on a clear night.
00:04The only thing you need to do is find the Big Dipper.
00:07Those two stars on the end of the Dipper's cup point the way to the North Star.
00:12See?
00:13It's the tip of the handle of the Little Dipper, or the tail of the Little Bear.
00:16It's in the constellation Ursa Minor, over there.
00:20People have been watching the North Star for centuries.
00:24This bright star is also known as Polaris.
00:27It's situated almost directly over our planet's North Pole, which makes it a great landmark
00:32for a traveler without a compass, or a GPS on their smartphone.
00:37It's also Earth's closest Cepheid.
00:40That's what we call a star that pulses regularly in brightness and diameter.
00:44Polaris is also part of a binary system of two stars.
00:48It's got a dimmer sister.
00:50It's known as Polaris B.
00:52You can actually see it circling the North Stars from Earth.
00:57But the more astronomers watch Polaris, the less they understand.
01:01The problem is, no one can agree on how big or distant the star is.
01:06Scientists have several ways to estimate the mass, age, and distance of a star like Polaris.
01:12One method is called the stellar evolution method.
01:16After studying the brightness, color, and rate of pulsation of a star, experts use this
01:21data to figure out how big or bright it is, as well as what stage of life it's in.
01:27Once these details are clear, it's not hard to find out how far a star actually is.
01:33It's simple math once you know the luminosity of a star in real life and how dim it looks
01:37from our planet.
01:40Such models are especially precise for stars like Polaris because the rate of their pulsing
01:44is directly related to their brightness.
01:47This makes it easy to figure out the distance to any of those stars.
01:52Astronomers trust this method so much that Cepheids have become an important tool for
01:56measuring distances all across the universe.
02:00At the same time, there are other ways to study the North Star, and they don't agree
02:04with the stellar evolution models.
02:07Polaris is a so-called astrometric binary.
02:10It means you can see its companion going around it.
02:13It looks as if a circle is being drawn around the bigger star.
02:18To complete one orbit, the smaller star needs around 26 years.
02:23Even though astronomers haven't made detailed observations of Polaris B's full circuit,
02:28they've seen enough to know what its orbit looks like.
02:32Using this information, one can apply Newton's laws of gravity to calculate the masses of
02:36the two stars.
02:37Combined with the Hubble Space Telescope's new measurements, these calculations lead
02:42to very precise numbers.
02:44Polaris is supposed to be around 3.45 times the mass of the Sun, but that's much less
02:50than the mass you get from stellar evolution models.
02:53They suggest a value of almost 7 times the mass of the Sun.
02:58But there's another reason why this star system is weird.
03:01After calculating the ages of the stars, researchers concluded that Polaris B is much older than
03:07its bigger sibling, but it's extremely unusual for a binary system.
03:12Normally, both stars are of the same age.
03:16One explanation might be that at least one of the measurements is simply wrong.
03:20After all, Polaris is a difficult star to study.
03:23Since it's positioned above our planet's north pole, it's outside the field of view of most
03:29telescopes.
03:30As for those telescopes that do have the needed equipment for measuring the star's properties
03:34precisely, they're typically used for studying much more distant and fainter stars.
03:40Polaris is simply too bright for such instruments.
03:43It blinds them.
03:44There's a theory that the main star of the Polaris system was once two stars, but they
03:49collided a few million years ago.
03:52Such a binary collision could rejuvenate stars by pulling in extra material and making the
03:56stars look as if they went through the fountain of youth.
04:00It would also explain some other oddities, since stars that appear as a result of binary
04:05collisions don't fit stellar evolution models.
04:08Unfortunately, so far, none of the theories have been confirmed.
04:13The north star is actually a big deal.
04:16Earth is spinning non-stop, which causes the sun to rise and set and stars to travel across
04:21the sky.
04:23Our planet is also tilted.
04:25That's why we have seasons.
04:27If we drew a line through the axis Earth spins around and extended it over 300 light-years
04:33past the North Pole, at the end of that imaginary line, there would be the north star.
04:38It stays almost exactly at the same spot in the sky at all times, and always points the
04:43way north.
04:44It's really important for navigation.
04:47People heavily relied on it in the days before GPS.
04:50If you were standing on the equator, Polaris would be right at the horizon.
04:55At the North Pole, it would seem to be right over your head.
04:58In other words, using the star's height in the sky, you can not only figure out the needed
05:03direction, but also understand where you are on Earth.
05:07Curiously, there's no south star.
05:10There isn't a bright enough star right above the south pole.
05:13But one day we might get such a star.
05:16When you spin a top on the table, its end moves in a circle.
05:20We know this phenomenon as precession.
05:23Earth behaves in the same way, and the north and south poles won't always point towards
05:27the same spots in the sky.
05:30In the next 26,000 years, it may cause the north star to change from Polaris to a few
05:35other stars and back again.
05:38One day, the title of the north star will go to Vega.
05:41It's the fifth brightest star in the night sky and the second brightest in the northern
05:45celestial hemisphere.
05:47Vega has another name, Alpha Lyrae.
05:51That's because it's the main star of the Lyrae constellation.
05:54Vega has been one of the most crucial stars to people since ancient times.
05:58It's very bright and blue, hence very recognizable.
06:03Vega was the north star several thousand years ago, and it'll regain this status in 12,000
06:08years or so.
06:10This star is located a mere 25 light-years from Earth.
06:13It's just 450 million years old, which makes it way younger than our own 4.6 billion-year-old
06:19star system.
06:21Astronomers study Vega to learn more about star systems in the early stages of their
06:26formation.
06:27Vega is almost directly overhead at mid-northern latitudes on a summer night.
06:32It hides behind the horizon for only seven hours a day.
06:35You can see it on any night of the year.
06:38If you travel farther south, you'll find out that Vega lies below the horizon for longer
06:43periods of time.
06:45But in Alaska, northern Canada, and some parts of Europe, Vega never sets.
06:50Vega's blue-white light is bright enough to be featured a lot in ancient cultures, from
06:55the Chinese, to the Polynesians, to the Hindus.
06:59Vega's name can also be translated as falling or swooping.
07:03This is a reference to the times when people regarded this constellation as a swooping
07:07vulture, not a lyre.
07:10Vega was also the first star to get photographed, other than the sun, of course.
07:15To do it, astronomers at Harvard College Observatory used a 15-inch refractor, and it happened
07:21again in 1850.
07:23Around two decades later, an amateur astronomer broke down Vega's light to reveal various
07:28elements making up the star.
07:30In 2006, thanks to telescopic observations, scientists found out that Vega was whipping
07:36around so fast that its poles were several thousand degrees warmer than its equator.
07:41The star rotates every 12.5 hours and is at 90% of its critical rotation speed.
07:47That's the velocity at which an object can tear itself apart.
07:52In 2013, researchers announced that they had discovered an asteroid belt around Vega.
07:57It means there might be planets somewhere out there among space rocks.
08:02There are two areas, an outer region that contains icy asteroids and an inner region
08:08with warmer space rocks.
08:11Scientists can examine bright stars like Vega using NASA's mission called TESS, which
08:16stands for Transiting Exoplanet Survey Satellite.
08:20It was launched in 2018 to conduct an all-sky survey.
08:24The main goal of this mission is to search for exoplanets, but the satellite can also
08:29look for star variability.
08:32By examining such stars as Vega, TESS can help scientists learn more about the early
08:37stages of star evolution.
08:39That's it for today!
08:41So hey, if you pacified your curiosity, then give the video a like and share it with your
08:45friends!
08:46Or if you want more, just click on these videos and stay on the Bright Side!