Search PBS Space Time


2022-10-12: The REAL Possibility of Mapping Alien Planets!

  • 06:05: ... is the “flagship” model,   in which a single craft with a 1-2 meter  telescope is sent to do the work. The second   is the string ...
  • 07:45: ... space agency sent the IKAROS   probe to Venus using a 20 meter solar sail, and plenty more solar sails missions are in the ...

2022-09-28: Why Is 1/137 One of the Greatest Unsolved Problems In Physics?

  • 03:28: ... charge of the electron is in Couloumbs,  the speed of light in meters per second, vacuum permittivity and Planck's constant also have their ...
  • 09:47: Transmit, say, the value for the speed of light - 299,792,458 m/s, and you also have to explain what a meter and a second are.

2022-09-21: Science of the James Webb Telescope Explained!

  • 02:15: ... has a 2.4 meter diameter mirror - the NGST had to be much bigger - 8m diameter to make ...

2022-07-27: How Many States Of Matter Are There?

  • 10:14: But if you increase the people-density to around 5 per square meter or more, a phase transition occurs.

2022-06-22: Is Interstellar Travel Impossible?

  • 11:42: ... against this radiation at 20% c, as would be a shield of water a meter thick - perhaps the best option because you’re carrying that water ...
  • 12:04: If you want to travel at speeds closer to that of light, you need up to several meters of titanium or tens of meters of water.
  • 13:09: ... meter-thick shell of water around the entire ship would do the trick, but would add ...

2022-05-04: Space DOES NOT Expand Everywhere

  • 09:16: ... to re-grid it at any point. What was once a millimeter might become a meter and the meter becomes a kilometer, but we can just redefine everything ...

2022-03-08: Is the Proxima System Our Best Hope For Another Earth?

  • 13:19: ... building and planning a new generation of giant telescope - 30 to 100 meters in diameter, which should be sensitive enough to detect emission lines ...

2022-02-23: Are Cosmic Strings Cracks in the Universe?

  • 07:33: ... of energy, which gives it the mass of the planet Mars for every 100 meters of ...

2022-02-10: The Nature of Space and Time AMA

  • 00:03: ... in to a higher density inside that uh you region there are more meters per meter in the absence of the gravitational field now the other ...

2021-09-15: Neutron Stars: The Most Extreme Objects in the Universe

  • 06:38: ... we’ve gone down a few hundred meters, we see nuclei that can’t even exist outside   a neutron star. ...

2021-06-16: Can Space Be Infinitely Divided?

  • 00:00: ... times and they’re a single Planck-length apart - 1.6x10^-35 meters. Surely we can keep going - .8,   .4, .2 x10^-35 m? Bizarrely, ...

2021-06-09: Are We Running Out of Space Above Earth?

  • 15:16: Two hundredths of a milligram is giant compared to the 1.6x10^-35 meters of the Planck length or the 5x10^-44 seconds of the Planck time.

2021-05-25: What If (Tiny) Black Holes Are Everywhere?

  • 06:41: Such a black hole would have an event horizon of around 10^-35 meters - the Planck length.

2020-08-24: Can Future Colliders Break the Standard Model?

  • 02:53: Its four meter ring collided electrons and positrons.
  • 03:19: The Americans soon followed up with a 12 meter electron-electron collider with a similar luminosity to VEP-1 but higher energies than even the AdA.
  • 17:04: Well space isn’t really empty - there’s an average density of one atom per cubic meter, so technically sound is possible.

2020-07-28: What is a Theory of Everything: Livestream

  • 00:00: ... circular tunnel on the border of france and switzerland 100 meters underground the large hadron collider and we accelerate protons to 13 ...

2020-04-28: Space Time Livestream: Ask Matt Anything

  • 00:00: ... because we define the length of the second and we define you know the meter and so we end up with a certain number of meters per second but I like ...

2020-04-22: Will Wormholes Allow Fast Interstellar Travel?

  • 15:35: ... between 1 particle per cubic centimeter and 1 particle per cubic meter. It's vacuum-y enough to kill you fast, but there's enough of the stuff ...

2020-01-06: How To Detect a Neutrino

  • 03:20: ... (𝘴𝘰𝘧𝘵 𝘢𝘯𝘥 𝘴𝘱𝘢𝘤𝘦𝘺 𝘢𝘨𝘢𝘪𝘯) ♪ The beam then passes through several hundred meters of solid rock, which blocks the muons, ♪ ♪ The beam then passes through ...

2019-09-30: How Many Universes Are There?

  • 03:59: Every 10^-32 seconds one cubic meter of volume becomes 10^78 cubic meters, which is approximately the volume of our entire universe.

2019-09-23: Is Pluto a Planet?

  • 17:24: A couple of meters of Martian rock above your head is plenty to protect against space radiation and micrometeorites.

2019-09-16: Could We Terraform Mars?

  • 07:12: We need about 10,000 kg of material per square meter to duplicate Earth’s atmospheric pressure.
  • 07:35: So to get 10 tons of CO2 for every square meter on the surface of Mars you’d have to dig down over 10 meters – across the entire planet!
  • 09:42: ... ice cap water would cover the entire surface to about 30 meters – which is not enough to start a proper water cycle or have oceans, but ...
  • 14:28: ... we wanted to cover, say, 10% of the Martian surface with a 300 meter tall worldhouse, it'd require several orders of magnitude less material ...

2019-08-19: What Happened Before the Big Bang?

  • 09:27: A millionth of a gram in a space 10^(-35) meters across should do the trick.

2019-08-12: Exploring Arecibo in VR 180

  • 01:02: ... aligned to create that spherical surface as I said it's over 300 meters in diameter That's a surface area of 26 football fields And no you can't ...

2019-07-01: Thorium and the Future of Nuclear Energy

  • 00:00: ... too cheap to meter That was the promise of nuclear power in the 1950s at least according to ...

2019-06-20: The Quasar from The Beginning of Time

  • 00:40: ... 4,200 meters, the oxygen up here is 60% sea level, but astronomers deal with it ...

2019-06-06: The Alchemy of Neutron Star Collisions

  • 13:02: ... out the density of the universe is roughly one hydrogen atom per square meter the universe is now around 1,100 times larger than it was then so can I ...

2019-03-13: Will You Travel to Space?

  • 05:59: Unity is dropped at 15,000 meters by its carrier, White Night, after which it blasts it's rocket engine sending it into a sub-orbital flight.

2019-02-07: Sound Waves from the Beginning of Time

  • 06:02: The speed of sound dropped from half the speed of light to only hundreds of meters per second.

2018-12-20: Why String Theory is Wrong

  • 03:43: Shrink it down to around 10 to the power of negative thirtieth of a meter, so it's only visible to things equally miniscule.

2018-11-21: 'Oumuamua Is Not Aliens

  • 01:53: It appears to be a few hundred meters long but only a few tens of meters cross.
  • 05:09: ... and Loeb calculate that a 50 meter wide sheet less than a millimeter thick and made of a highly reflective ...

2018-10-10: Computing a Universe Simulation

  • 04:58: So our Bekenstein bound hard drive needs to be roughly 4 by 10 to the power of 80 Planck areas, corresponding to 40 billion square meters.

2018-09-20: Quantum Gravity and the Hardest Problem in Physics

  • 05:57: ... better than a Planck length around 10 to the power of negative 35 of a meter, the amount of energy you would need to put into that region of space ...

2018-09-12: How Much Information is in the Universe?

  • 02:48: ... measure of distance, at around 1.6 times 10 to the negative 35 meters. ...
  • 07:54: Its event horizon is around 12 billion meters, giving it a surface area of 10 to the power of 90 to 10 to the power of 91 Planck units.

2018-06-27: How Asteroid Mining Will Save Earth

  • 02:01: They range from a meter or so to hundreds of kilometers in diameter, and they live primarily in the asteroid belt between Mars and Jupiter.

2018-05-16: Noether's Theorem and The Symmetries of Reality

  • 11:00: It has a 35-square meter collecting area, compared to Gaia's 0.7 square meters.

2018-04-04: The Unruh Effect

  • 09:38: You need to accelerate at a rate of 10 to the power of 20 meters per second squared to increase the temperature via a single degree Kelvin.

2018-03-21: Scientists Have Detected the First Stars

  • 08:13: Then, half mv squared gives us its velocity, around 80 meters per second.

2018-02-28: The Trebuchet Challenge

  • 03:51: As Archimedes once said, "give me a lever and a place to stand, and I will move the earth," or hurl a 90-kilogram stone over 300 meters.
  • 06:54: Let's say you drop a five-ton counterweight from a height of eight meters above the ground.
  • 07:10: ... counterweight swings to a lowest point 1 meter above the ground and continues its arc, ultimately rising to a height of ...
  • 07:20: Meanwhile, the stone travels 300 meters to strike the fortress wall 15 meters above the ground.

2018-02-21: The Death of the Sun

  • 11:46: I suppose you'd have preferred some sort of device that can launch a 90 kilogram stone over 300 meters.

2018-01-10: What Do Stars Sound Like?

  • 04:45: At the same time, gas moves vertically in and out during the same oscillation, reaching velocities of 0.1 meters per second.

2017-12-20: Extinction by Gamma-Ray Burst

  • 10:50: Well, based on its brightness and variations in that brightness, the body is estimated to be 180 meters long and maybe 30 meters wide.
  • 10:58: Now, assuming an albedo or reflectivity of 0.1, that gives it a volume of around 130,000 cubic meters.
  • 11:06: A typical asteroidal density is 2,000 kilograms per cubic meter.

2017-12-13: The Origin of 'Oumuamua, Our First Interstellar Visitor

  • 01:59: ... like a cigar or the monolith from "2001: A Space Odyssey." Hundreds of meters long, it's size and shape can't be determined directly from the ...
  • 02:39: That suggests the surface to at least one meter depth is rocky like an asteroid rather than icy like a comet.

2017-11-22: Suicide Space Robots

  • 07:21: ... nearly five tons of TNT in kinetic impact energy and forming a crater 30 meters ...

2017-11-02: The Vacuum Catastrophe

  • 10:18: The average density in the filaments is maybe 20 baryons per cubic meter.

2017-09-28: Are the Fundamental Constants Changing?

  • 02:03: Its value today is 299,792,458 meters per second in a vacuum.
  • 02:31: The meter is officially defined as the distance light travels in one 299,792,458th of a second.

2017-09-20: The Future of Space Telescopes

  • 02:50: ... starshade will be up to 50 meters in diameter and hover 80,000 kilometers in front of the telescope, ...
  • 06:08: Imagine an opaque disk of 100 meters to a kilometer in diameter, suspended in front of a satellite detector.
  • 09:11: Scientists could expand the aperture to tens of meter in diameter.

2017-08-24: First Detection of Life

  • 09:03: ... gigantic 6.5 meter diameter mirror and incredibly sensitive infrared spectrograph, coupled ...

2017-04-19: The Oh My God Particle

  • 05:33: At the lowest energies, the cosmos flings one particle every second per square meter of the Earth's surface.

2017-04-05: Telescopes on the Moon

  • 06:06: Grind it into shape and coat it with aluminum, and it may be possible to build a 50 meter mirror on the moon.
  • 06:41: It spins a six meter dish of mercury at 8.5 revolutions per minute, creating the cheapest telescope of that size ever constructed.
  • 07:49: Lower gravity could facilitate the formation of large liquid mirrors, maybe up to 100 meters across.

2017-02-15: Telescopes of Tomorrow

  • 00:57: With a diameter of 6.5 meters, compared to Hubble's 2.4, it has over five times Hubble's collecting area.
  • 05:02: Together, they provide an effective aperture, 24.5 meters in diameter, and a collecting area over 80 times Hubble's and nearly 15 times Webb's.
  • 07:48: The Large Synoptic Survey Telescope's primary mirror spans 8.4 meters-- 3 and 1/2 times larger than Hubble's.

2016-11-30: Pilot Wave Theory and Quantum Realism

  • 14:51: ... below that crust, there's a region centimeters to meters deep in which you have significant impurities of electrons and protons ...

2016-05-04: Will Starshot's Insterstellar Journey Succeed?

  • 03:51: ... Starshot will be comprised of a sail around a meter in diameter that's made of an advanced meta-material-- a nano-fabricated ...

2016-03-30: Pulsar Starquakes Make Fast Radio Bursts? + Challenge Winners!

  • 04:16: And it 6.65 by 10 to the minus 29 meters squared.
  • 05:57: 46.6 billion light years in radius now, translates to 42.3 million light years then, which is a volume of 2.7 times 10 to the 71 cubic meters.
  • 06:11: ... evenly and we get that there were 200 million electrons in every cubic meter at the moment of ...
  • 06:21: That's way up from the 0.2 electrons per cubic meter that we find now.
  • 07:07: ... we say the cross-sectional surface area of the column is a square meter, then each 1-meter length of the column has a fraction blocked equal to ...

2016-03-16: Why is the Earth Round and the Milky Way Flat?

  • 07:55: ... the upward acceleration we feel due to the Earth's rotation is 0.03 meters per second squared, compared to 9.8 meters per second squared due to ...

2016-02-03: Will Mars or Venus Kill You First?

  • 05:49: ... you can actually shield against a coronal mass ejection with around a 1 meter thickness of water or potentially food, human waste products, ...

2015-11-25: 100 Years of Relativity + Challenge Winners!

  • 03:53: ... the average acceleration comes out to around 10 to the power of minus 9 meters per second squared or around one ten billionth of Earth's surface ...
  • 04:06: Our spacecraft is hovering 325 meters from the center of mass of Apophis.

2015-11-18: 5 Ways to Stop a Killer Asteroid

  • 01:25: A rock less than 10 meters in diameter vaporizes harmlessly in the atmosphere.
  • 01:40: Meteors 20-100 meters in size have the kinetic energy equivalent of a thermonuclear explosion.
  • 01:54: For a rock around 500 meters in diameter, the strike will have the energy equivalent of all currently operational nuclear weapons in the world.
  • 03:14: ... are a couple of 500 meter bad boys that have a very small chance of hitting in the late 2100s, and ...
  • 07:27: ... simulations of HAIV team, a one megaton H-bomb should break up a 500 meter asteroid nicely, although it depends on the structure of the ...

2015-08-05: What Physics Teachers Get Wrong About Tides!

  • 07:45: Second, in the simple model of a water world Earth, the math says that the water level should vary by about 3/4 of a meter between high and low tide.
  • 07:54: But some places see smaller tides than this while other places, like the Bay of Fundy in Canada, have tidal swings of over 10 meters each day.

2015-06-03: Is Gravity An Illusion?

  • 06:32: It's really accelerating downward at 9.8 meters per second squared.

2015-05-06: Should the First Mars Mission Be All Women?

  • 08:21: So go 9.8 meters per second per second acceleration in one direction.

2015-04-29: What's the Most Realistic Artificial Gravity in Sci-Fi?

  • 03:05: Let's start with the iconic scene of Frank Poole jogging around the rotating command module in "2001: A Space Odyssey." Poole's height is 1.8 meters.
  • 03:12: Using him as a ruler, the radius of the module he's running in looks to be about 8 meters, give or take.
  • 03:17: ... produce 1 Earth g of effective gravity at its surface or 10 meters per second squared, our earlier formula says the ring would need to ...
  • 04:14: Poole himself would feel 20% heavier at his leisurely 2 meters per second jogging speed and feel pressed down into the ground.
  • 04:35: For example, any time you stand up from a chair, your head has an upward speed of about 1 meter per second.

2015-04-08: Could You Fart Your Way to the Moon?

  • 03:17: But I couldn't get one, so I used the 3 meters per second value I kept seeing on the internet.
  • 03:38: That's 15 centimeters an hour, 3.7 meters per day, 26 meters in a week, or 1.3 kilometers per year.
  • 03:57: Suppose you were stranded at rest 10 meters away from the air lock door on the ISS.
  • 04:21: ... the description used high speed photography to get an answer closer to 4 meters per second, right around my estimate for the speed of a ...
  • 04:42: Mine was in the same 3 to 4 meter per second range we've seen all episode.
  • 04:59: About 500 to 700 times higher recoil velocity, a little over 77 meters per hour, or enough to get you back to the ISS in under eight minutes.

2015-04-01: Is the Moon in Majora’s Mask a Black Hole?

  • 03:45: I've worked out the algebra using that MatPat's measurement of a mere 30-ish meters for the radius of Termina's moon.

2015-03-18: Can A Starfox Barrel Roll Work In Space?

  • 05:42: ... there are still lots of unanswered questions, including what a space meter is, which is apparently the official unit of measurement in the "Star ...

2015-03-11: What Will Destroy Planet Earth?

  • 03:07: All they changed from one initial set up to another was Mercury's current position by about a meter.

2015-02-18: Is It Irrational to Believe in Aliens?

  • 07:11: The Gentleman Physicist points out that Super Mario World could be a platform accelerating through space with rockets at 70 meters per second squared.

2015-02-11: What Planet Is Super Mario World?

  • 00:26: Now on Earth, an object rising straight upward will lose 9.8 meters per second of its speed each second.
  • 00:32: Likewise, a falling object will gain 940 meters per second of extra speed each second.
  • 00:41: One second later, it's moving at 10 meters per second.
  • 00:44: Two seconds later, 20 meters per second.
  • 00:58: ... rate, around 10 meters per second per second, or 10 meters per second squared, is called the ...
  • 01:50: Careful internet research, which you can also find in the description, reveals that Mario's official stature is 1.55 meters, or about 5'1" tall.
  • 02:17: Multiply that by his height of 1.55 meters, and you find that his jump height is almost 3 and 1/2 meters.
  • 02:40: If we set h to 3.5 meters and t to 0.3 seconds, we get a final g value of around 78 meters per second per second, or almost 8 Earth g's.
  • 03:43: If Mario were on Earth, he would have a takeout speed of over 50 miles an hour and be able to jump about 28 meters, or over 90 feet.
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