Department
Space
Everything beyond the sky. 66 case files (9 cross-filed from other departments).
DID YOUKNOW?Temperature TilesDD-754
Temperature Tiles
The Space Shuttle's thermal protection system used about 24,300 tiles, mostly silica-fiber ceramic, to shield the orbiter during reentry. The highest-temperature tiles were rated for about 1,260 degrees Celsius, and because the material is largely empty space it conducts heat so poorly that a tile glowing hot in the middle can be held at the edges moments after leaving a furnace. The footage, credited to asgardia_space, shows a tile being heated and then held by hand.
DID YOUKNOW?Cosmic FreezerDD-752
Cosmic Freezer
The coldest place in the universe isn't the void between galaxies. It's a dying star's breath, 5,000 light-years away, at 1 K (-272 °C).
DID YOUKNOW?Rocket Stage ReleaseDD-697
Rocket Stage Release
Stage separation is how a multistage rocket discards empty stages to save mass and reach orbit. Separation systems use explosive bolts or frangible joints, pneumatic pushers or springs, and sometimes small gas thrusters to push the spent stage away; the next stage then ignites its engine as the old stage falls away. The footage, credited to aerospacefanclub, shows an onboard view of a stage separating above Earth.
DID YOUKNOW?Chicxulub CraterDD-693
Chicxulub Crater
The Chicxulub crater is a buried impact structure about 180 to 200 km across, centered near the town of Chicxulub on Mexico's Yucatán coast and extending under the Gulf of Mexico. It formed about 66 million years ago when an object roughly 10 km wide struck Earth, and the impact is tied to the end-Cretaceous mass extinction. Nothing of the crater is visible at the surface. It lies under about 1 km of younger sediment, and a ring of sinkholes (cenotes) traces its outline. Pemex geophysicists Glen Penfield and Antonio Camargo found it while searching for oil. It was identified as the impact site in 1991. In 2016, IODP-ICDP Expedition 364 drilled its peak ring, and a 2024 ruthenium-isotope study concluded the impactor was a carbonaceous asteroid that formed beyond Jupiter, not a comet.
DID YOUKNOW?Solar SailingDD-039
Solar Sailing
Light has no mass but does carry momentum. When photons bounce off a mirror-like sail, they push it twice: once when they arrive and again when they reflect. The force (solar radiation pressure) is tiny, so sails have to be huge and spacecraft light. In the vacuum of space, though, the push never stops. Japan's IKAROS first flew a solar sail between planets in 2010. The Planetary Society's LightSail 2 showed a CubeSat could raise its orbit with sunlight, and NASA's ACS3 (launched April 23, 2024) is testing lightweight carbon-fiber booms for an 80 m² sail. By tilting the sail, a craft can speed up, slow down or 'tack' to change its orbit.
DID YOUKNOW?SpacewalkerDD-652
Spacewalker
On February 7, 1984, during shuttle mission STS-41B, Bruce McCandless II made the first untethered free flight in space. He was flying NASA's Manned Maneuvering Unit (MMU), a backpack propelled by nitrogen gas jets and steered with hand controllers. NASA says he flew out to 150 ft, came back, then flew out to about 320 ft (about 98 m) from Challenger before returning. Crewmate Robert L. Stewart flew the same MMU later in that spacewalk, so both men made untethered flights on the mission's first EVA. The flights were practice for repair and retrieval work. Two satellites deployed on STS-41B ended up in useless orbits, and in November 1984, STS-51A astronauts Joseph Allen and Dale Gardner used MMUs to help capture them. That was the last time the MMU flew. Later shuttle spacewalkers stayed tethered, with the smaller SAFER unit as a backup.
DID YOUKNOW?Solar ProminenceDD-038
Solar Prominence
A solar prominence is a huge loop of relatively cool, dense plasma (electrically charged hydrogen and helium) hanging in the sun's million-degree corona. Twisted magnetic fields rooted in the photosphere hold it up. Prominences form in about a day and can sit quietly for months, looping hundreds of thousands of miles above the surface. When the magnetic structure becomes unstable, the prominence erupts and usually becomes the bright core of a coronal mass ejection (CME). CMEs can carry billions of tons of material at speeds from under 250 km/s to nearly 3,000 km/s, and the fastest Earth-directed ones arrive in 15 to 18 hours.
DID YOUKNOW?On A GlideDD-615
On A Glide
The Space Shuttle orbiter came home without engine power. NASA's Glenn Research Center explains that once the external tank was gone, the main engines had no propellant, so the shuttle returned as an unpowered glider. It had a low lift-to-drag ratio because it had to slow from about 17,300 mph to about 250 mph. About an hour before landing, a deorbit burn dropped it out of orbit. It entered the atmosphere nose-first at a 40° angle of attack to limit heating, and computers controlled its speed with a series of banking roll reversals. NASA's Kennedy Space Center fact sheet says commanders took manual control for the final approach during subsonic flight, usually about 22 miles (35 km) from touchdown. The initial approach glide slope was 20 degrees, more than six times steeper than an airliner's 3 degrees. Because the orbiter was unpowered, it had no go-around capability. It touched down at 213 to 226 mph. From 1991, orbiters were fitted with a 40-foot drag parachute, deployed as the nose came down, plus carbon brakes. Of 133 successful landings, 78 were at Kennedy's 15,000-foot Shuttle Landing Facility, 54 at Edwards Air Force Base in California and one, STS-3, at White Sands in New Mexico. The program flew 135 missions between April 12, 1981, and July 21, 2011, when Atlantis made the final landing. The footage shows an orbiter gliding over Florida wetlands, touching down and rolling out with its drag chute.
DID YOUKNOW?Self-Made ModularDD-061
Self-Made Modular
Self-reconfigurable modular robots are machines built from many units that can rearrange how they connect, to change shape for new tasks or to repair themselves. The idea of applying a common connector to a whole robot dates to Toshio Fukuda's CEBOT in the late 1980s. About 30 systems had been built by the time of the Wikipedia survey, but demonstrations have topped out around 50 units, and the promised robustness and low cost haven't been shown. The footage isn't one of those systems. It shows GITAI's Lunar Rover and three Inchworm robots with grapple ends building a 5-meter communications tower in a desert simulating the Moon. GITAI and KDDI announced the demo in December 2023 and March 2024. The robots then attached an antenna, connected power and took the tower apart again.
DID YOUKNOW?Lunar RovingDD-609
Lunar Roving
The Lunar Roving Vehicle (LRV) was the electric car of the last three Apollo missions. According to NASA, it made its debut on July 31, 1971, when Apollo 15's David Scott and James Irwin drove it. Rovers were also driven on Apollo 16 (John Young and Charles Duke) and Apollo 17 (Gene Cernan and Harrison Schmitt), each used for three traverses, one per day. NASA's Space Science Data Coordinated Archive gives its mass as 210 kg and its design payload as 490 kg (Wikipedia gives 440 kg), so it could indeed carry more than twice its own mass. The frame folded so it could ride to the Moon in a bay of the Lunar Module. Each of its four wire-mesh wheels had its own 0.25-horsepower electric motor, powered by two 36-volt silver-zinc batteries that were not rechargeable. Boeing built the rovers, with Delco as a major subcontractor. The original $19 million contract ended up costing $38 million for four rovers, one of which was used for spare parts. Apollo 15's rover was driven 27.8 km, and Apollo 17's went 35.9 km, with a farthest distance of 7.6 km from the lander. The three rovers are still on the Moon. The footage is a view from the rover's TV camera, wrapped in gold-colored thermal insulation, looking across the lunar surface.
DID YOUKNOW?Northrop GrummanDD-604
Northrop Grumman
Northrop Grumman is a US aerospace and defense company based in Falls Church, Virginia. Its 2025 annual report (Form 10-K) says the company began in 1939 in Hawthorne, California, as Northrop Aircraft Incorporated, founded by Jack Northrop. Northrop Corporation was a principal developer of flying-wing designs, which, according to the company's heritage page, led to the B-2 stealth bomber. In 1994 it acquired the Grumman Corporation, which built the Apollo Lunar Module, and the combined company was renamed Northrop Grumman. The heritage page lists more than 20 companies it has since absorbed, including Westinghouse's defense electronics business (1996), Litton (2001), TRW (2002), Scaled Composites (2007) and Orbital ATK (2018). The 10-K reports 2025 sales of $41.954 billion, about 84% of them to the US government, and about 95,000 employees. It lists the B-21 Raider long-range strike bomber for the US Air Force and support for the B-2 Spirit among its key programs. For NASA's James Webb Space Telescope, launched on December 25, 2021, Northrop Grumman was the prime contractor. It designed and built the deployable sunshield, provided the spacecraft and integrated the whole observatory. NASA describes the sunshield as five layers of Kapton coated with reflective metal, each thinner than a human hair, about the size of a tennis court. The Reel uses company footage, including a hangar with aircraft, a holographic globe, an underwater drone, a cleanroom and a satellite.
DID YOUKNOW?Mars NightsDD-603
Mars Nights
NASA describes Mars's atmosphere as thin and made up mostly of carbon dioxide, with nitrogen and argon. Astronomy magazine puts it at about 1% of Earth's and notes that with so little air, the stars barely twinkle, and with no light pollution the nights are very dark. Dust is the catch. Rover observations show that even straight overhead, suspended dust dims stars by about one magnitude, and by up to four magnitudes near the horizon. When the sky is clear, NASA's Opportunity rover could just pick out magnitude 6 stars, about the limit of the human eye. Dust also makes Martian twilight last much longer. The constellations look the same as from Earth. BBC Sky at Night Magazine explains that Mars is so close to Earth, compared with the distance to the stars, that there's no visible parallax shift: Orion and Cassiopeia keep their shapes. What does change is the sky's pivot. Mars's axis points between Deneb in Cygnus and Alderamin in Cepheus, near only a faint star, so Mars has no bright North Star like Polaris. Earth appears as a bright morning or evening 'star', with the Moon beside it. On January 31, 2014, NASA's Curiosity rover photographed exactly that, about 80 minutes after sunset. Mars's two moons are visible too: Phobos rises in the west, crosses the sky in about four hours and visibly changes phase along the way, while Deimos looks like a very bright star. The footage shows a dense Milky Way-style star field above dark red ground, an artistic composite rather than a rover photograph.
DID YOUKNOW?Alcubierre DriveDD-060
Alcubierre Drive
In 1994, physicist Miguel Alcubierre showed that Einstein's general relativity allows a 'warp bubble': spacetime contracts ahead of a ship and expands behind it, so the ship can cover distance faster than light as seen from outside while never locally outrunning light inside its bubble. It is a mathematical solution, not a machine. The geometry requires exotic matter with negative energy density. Quantum physics allows only tiny, fleeting amounts of negative energy, and in 1997 Michael Pfenning and Lawrence Ford estimated that a 100-meter bubble would need far more negative energy than the mass-energy of the visible universe. Later papers have trimmed the estimates and found other problems, including how a crew could ever start or steer the bubble. No warp drive has been built or tested.
DID YOUKNOW?Stellar BirthDD-037
Stellar Birth
Stars are born in giant molecular clouds: cold (about 10 to 20 K), dusty clouds made mostly of molecular hydrogen, up to about 300 light-years across, and holding enough gas for anywhere from 10 to 10 million suns. Something has to tip a dense region into collapse, such as a supernova shock wave. Gravity then squeezes a core by a factor of nearly 10^20 in density. The infalling gas heats up into a protostar whose core reaches several million kelvin. A protostar becomes a true star only when its core hits about 10 million K and hydrogen fusion starts. For a sun-like star, the process takes tens of millions of years.
DID YOUKNOW?Neutron SpinDD-058
Neutron Spin
Neutron stars are the collapsed cores left after massive stars explode as supernovae, an idea Walter Baade and Fritz Zwicky proposed in 1933. As the core shrinks to about the size of a city, conservation of angular momentum makes it spin much faster, like a skater pulling in her arms. Pulsars are neutron stars whose beams of radiation, from near their magnetic poles, sweep past Earth like a lighthouse. Jocelyn Bell and Antony Hewish detected the first one in 1967. Most pulsars turn only a few times a second at most. The ones that spin hundreds of times a second are millisecond pulsars, old neutron stars 'recycled' by matter and angular momentum from a companion star. The record holder, PSR J1748-2446ad, spins 716 times a second.
DID YOUKNOW?heat.DD-595
heat.
Rocket engines produce intense heat by burning propellants such as liquid hydrogen and liquid oxygen. The Reel says liquid-fueled engines like the Space Shuttle's produce exhaust above 3,000 degrees Celsius, hot enough to melt steel, and release energy at up to 10 gigawatts; I left the power figure attributed to the Reel. Launch pads use flame trenches to divert exhaust and water deluge systems to absorb heat and sound. The footage, credited to astronomy4u, shows a rocket launch.
DID YOUKNOW?Deluge DaysDD-594
Deluge Days
NASA's Stennis Space Center in Mississippi tests rocket engines and stages by bolting them to giant stands and firing them in place. Because the hardware doesn't move, the exhaust, which NASA says can reach 6,000 degrees Fahrenheit (about 3,300 degrees Celsius), pours into the same flame deflector for the whole test. Water keeps it from melting. Stennis's high-pressure industrial water system draws on a 66-million-gallon reservoir. For the Space Launch System core stage's Green Run tests in 2020 and 2021, the B-2 stand could receive 335,000 gallons a minute at 300 psi, enough to fill an Olympic pool in about two minutes. Most of it cooled the exhaust through the deflector, and about 87,000 to 92,000 gallons a minute formed a curtain of water to damp noise and vibration. A typical 500-second RS-25 engine test uses about 5 million gallons. Launch pads use water too. At Kennedy Space Center's Pad 39B, the ignition overpressure and sound suppression system dumps about 400,000 gallons in under 30 seconds, peaking around 1.1 million gallons a minute. NASA says SLS produces about 176 decibels at liftoff. The footage looks like a pad water-flow test, with columns of water erupting in front of a steel launch structure.
DID YOUKNOW?StarbaseDD-582
Starbase
Starbase is SpaceX's Starship build, test and launch site on the Boca Chica peninsula in Cameron County, Texas, about 20 miles east of Brownsville and close to the Mexican border. The area began as Kennedy Shores, a small subdivision founded in 1967 and later renamed Kopernik Shores; by the 2000s it was better known as Boca Chica Village and had only a handful of permanent residents. SpaceX started buying land there in 2012 and announced in August 2014 that Boca Chica would be its South Texas launch site, with limited construction that year and much larger work from about 2018. Prototype flight testing began in 2019. Elon Musk announced plans for a city called Starbase in March 2021, and SpaceX petitioned Cameron County for an incorporation vote in 2024. On May 3, 2025, voters approved incorporation 212 to 6, according to Cameron County's election results, and Bobby Peden, SpaceX's vice president of Texas test and launch, was elected mayor unopposed. The county commissioners court certified the result on May 20, 2025, making Starbase a Type C general-law city with a mayor and two commissioners. Supporters, including local economic development officials, point to jobs and tourism; some residents and conservation groups have raised concerns about land use, launch effects and the nearby wildlife refuge. The footage shows Starship hardware and the tall assembly buildings at the site.
DID YOUKNOW?Second ImpactDD-578
Second Impact
Ceres is the largest object in the main asteroid belt between Mars and Jupiter. Giuseppe Piazzi discovered it on January 1, 1801, and it was first hailed as a planet, then called an asteroid. Since August 24, 2006, it has been classed as a dwarf planet, the only one inside Neptune's orbit, though it also keeps its asteroid number, 1 Ceres. NASA's Dawn spacecraft orbited it from March 6, 2015, to the end of the mission on November 1, 2018. Dawn measured a mean diameter of 939.4 km and a mass of about 9.38 × 10^20 kg, about 40% of the whole asteroid belt's mass. It found a crust of ice, salts and hydrated minerals over a muddy interior, with brines that reach the surface in bright spots like those in Occator Crater. Ceres's orbit stays between 2.55 and 2.98 astronomical units from the Sun, well outside Earth's, so the Reel's collision is purely hypothetical. Still, the numbers are extreme. Anything falling to Earth hits at no less than Earth's escape speed, about 11.2 km/s. At 11 to 20 km/s, Ceres would carry about 6 × 10^28 to 2 × 10^29 joules of kinetic energy. That's my own back-of-envelope estimate (½mv²), not a published figure. A 2022 review in Nature Reviews Earth & Environment puts the Chicxulub impact that ended the age of dinosaurs at about 10^23 joules, so Ceres would deliver roughly half a million to two million times as much. Sleep and colleagues estimated in 1989 that an impactor of roughly 350 to 440 km could boil away Earth's oceans, and later models put the threshold nearer 700 km. Ceres is bigger than either. The footage is computer animation of a huge body striking Earth from orbit, with a glowing crater and a fireball sweeping across the planet.
DID YOUKNOW?AxisymmetryDD-054
Axisymmetry
Modelers often assume the gas around a black hole looks the same at every angle around the spin axis. Quantities then depend only on distance and polar angle, and a 3D simulation becomes a much cheaper 2D one. The shortcut has known limits. Cowling's anti-dynamo theorem (1933) says an axisymmetric magnetized flow can't regenerate its magnetic field, so 2D simulations lose the turbulence that drives accretion unless an artificial 'sub-grid' dynamo is added. And because infalling gas generally doesn't share the black hole's spin direction, many disks are expected to be tilted. Tilted disks break the symmetry and must be simulated in full 3D. The classic prediction that a thin disk's inner part aligns with the spin (Bardeen–Petterson, 1975) didn't appear in some GRMHD simulations of moderately thick disks.
DID YOUKNOW?Baikonur CosmodromeDD-570
Baikonur Cosmodrome
Buran was the Soviet Union's reusable spaceplane, built in response to the US Space Shuttle and launched on the Energia rocket. The orbiter Buran (1K) flew once, uncrewed, on November 15, 1988. It lifted off from Baikonur, circled Earth twice in 3 hours 25 minutes and landed automatically on the cosmodrome's runway. Funding dried up as the Soviet Union broke apart, and the program was suspended in 1993. The flown orbiter didn't survive. It was stored in Baikonur's main assembly building, MIK 112, which was originally built for the N1 Moon rocket. On May 12, 2002, the roof collapsed during repair work, killing eight workers and destroying Buran along with Energia hardware. The craft in the famous photos are two others, kept in a separate Assembly and Fueling Complex (MZK) at Site 112A. According to RussianSpaceWeb, the MZK is 150 m long, 80 m wide and 70 m high. Inside are orbiter 1.02, the second flight article, which was about 95–97% complete and never flew, and OK-MT, an engineering mockup. Both were moved there in 1995. Their doors later jammed, and RussianSpaceWeb calls the building a sarcophagus for both vehicles. Wikipedia, citing CNN, reports that a Russian-Kazakh company, Aelita, has owned them since 2005. Baikonur is in Kazakhstan. Under a 1994 agreement, Russia leases the whole Baikonur complex for $115 million a year, and the lease has since been extended to 2050. The footage looks down on an orbiter between rusting work platforms in the MZK, then shows the hall and the vehicles from the side.
DID YOUKNOW?Universal SizingDD-546
Universal Sizing
The observable universe spans about 93 billion light-years. Its oldest light has traveled about 13.8 billion years, but expansion has carried those regions much farther away since. The Milky Way is about 100,000 light-years wide with an estimated 100 to 400 billion stars, and the observable universe holds hundreds of billions to perhaps 2 trillion galaxies. The footage, credited to explainingtheuniverse, shows a zoom out through space.
DID YOUKNOW?Tidal ForcesDD-544
Tidal Forces
The Moon's gravity pulls the ocean into a bulge on the side facing it, and a second bulge forms on the far side because the Moon pulls Earth's center more strongly than the far ocean. As Earth rotates through both bulges, most coasts see two high and two low tides in about 24 hours and 50 minutes, a lunar day. The Sun's gravity adds smaller tides. The footage, credited to explainingtheuniverse, shows an animation of Earth's tidal bulges.
DID YOUKNOW?Neutron BinaryDD-542
Neutron Binary
In a binary neutron star system, the stars lose orbital energy by emitting gravitational waves, ripples in spacetime predicted by Einstein's general relativity. Their orbits shrink and speed up until they collide and merge. The first such merger was detected in gravitational waves and light on August 17, 2017 (GW170817). The footage, credited to astronomhub, shows an animation of two neutron stars merging.
DID YOUKNOW?One Small Fall for Man...DD-541
One Small Fall for Man...
During the Apollo Moon landings (1969-1972), astronauts sometimes fell over. Lunar gravity is about one-sixth of Earth's, and pressurized suits that protected them from extreme temperatures and micrometeoroids were bulky and stiff, making bending, turning and recovering balance difficult. Many adopted a bunny-hop gait to move efficiently. The footage, credited to galaxies, shows astronauts falling on the Moon.
DID YOUKNOW?StarlinkDD-529
Starlink
Starlink is a satellite internet service from SpaceX that provides broadband to underserved and remote areas. It uses a large constellation of small satellites in low Earth orbit that communicate with user dishes and ground stations. Older satellite internet relied on geostationary satellites with high latency; Starlink's much lower orbits shorten transmission time. The footage, credited to Starlink, shows dishes and a Starship deploying satellites.
DID YOUKNOW?SpaceXDD-522
SpaceX
SpaceX is a private aerospace company founded by Elon Musk in 2002 with the long-term aim of enabling Mars colonization. It developed the Falcon 9 and Falcon Heavy rockets, whose boosters land for reuse, and the Dragon capsule, the first commercial vehicle to carry astronauts to the International Space Station, in 2020. Its Starship is designed to be fully reusable for Moon and Mars missions. The footage, credited to Black Hole and SpaceX, shows launches, Dragon and Starship.
DID YOUKNOW?Mk-II AuroraDD-508
Mk-II Aurora
The Mk-II Aurora is a small, remotely piloted, reusable suborbital spaceplane built by New Zealand-based Dawn Aerospace. It takes off and lands horizontally on ordinary runways and is designed to eventually exceed 100 km. Its first rocket-powered flights were on March 29-31, 2023, at Glentanner Aerodrome on New Zealand's South Island, reaching about 315 km/h (196 mph); in November 2024 it flew supersonic. The footage, credited to cora.a.harris, shows the spaceplane.
DID YOUKNOW?Going Up?DD-503
Going Up?
A space elevator is a theoretical structure carrying cargo and people to space on a cable anchored at the equator and extending past geostationary orbit, about 35,786 km (22,236 miles) up, to a counterweight. Earth's rotation keeps the cable in tension, with the outward centrifugal effect balancing gravity. No known material is yet strong enough to build one. The footage, credited to tradzak, shows an animated ride up the cable.
DID YOUKNOW?The Space PerspectiveDD-500
The Space Perspective
Space Perspective, a Florida company, developed Spaceship Neptune, a pressurized capsule lifted by a hydrogen balloon to about 100,000 feet (30 km), where passengers would see Earth's curvature without rocket G-forces; a trip was planned to last about six hours, at $125,000 a seat. An uncrewed test flight reached that altitude in September 2024. When this Reel was posted, the company had furloughed most staff; it was evicted from its Titusville base in March 2025 and acquired by Spain's Eos X Space in July 2025. The footage, credited to TheSpacePerspective, shows the balloon launch.
DID YOUKNOW?Fire BallDD-499
Fire Ball
On Earth, hot gases rise and draw in fresh air, giving flames their familiar teardrop shape. In microgravity there is no buoyant convection, so oxygen reaches the flame only by diffusion and the flame spreads equally in all directions, forming a sphere that is often dimmer and bluer. The footage, credited to galaxies, shows combustion experiments in orbit.
DID YOUKNOW?Sea DragonDD-498
Sea Dragon
Sea Dragon was a 1962 concept for a huge two-stage rocket designed by Robert Truax at Aerojet. It would be built cheaply in a shipyard, towed to sea, ballasted upright and launched from the water, avoiding a launch pad. The first stage burned RP-1 and liquid oxygen, the second liquid hydrogen and oxygen, and it was meant to lift about 550 tonnes to low Earth orbit. It was never built. The footage, credited to newspaceenterprise, shows an animation of the launch.
DID YOUKNOW?Project OrionDD-496
Project Orion
Project Orion was a U.S. study from 1958 to 1965, led at General Atomics, of nuclear pulse propulsion: small nuclear explosions behind a spacecraft would strike a large pusher plate whose shock absorbers smoothed the thrust. It promised performance far beyond chemical rockets, with trips to Mars in weeks, but ended after the 1963 Partial Test Ban Treaty barred nuclear explosions in the atmosphere and space. The footage, credited to spaceman.in, shows an animated Orion craft.
DID YOUKNOW?Disk JetsDD-495
Disk Jets
Gas and even shredded stars spiraling toward a black hole form an accretion disk that heats through friction and glows. Magnetic fields threading the disk can launch relativistic jets, beams of particles accelerated to nearly the speed of light, perpendicular to the disk. The footage, credited to galaxies, shows an animation of an accretion disk and jets.
DID YOUKNOW?Why So Sirius?DD-490
Why So Sirius?
Sirius, also called the Dog Star in the constellation Canis Major, is the brightest star in the night sky, about 8.6 light-years away. It is a binary: Sirius A, a hot main-sequence star, and Sirius B, a white dwarf that was once a more massive, more luminous star before shedding its outer layers and collapsing. The footage, credited to galaxies, shows a twinkling star through a telescope.
DID YOUKNOW?Praise the Sun!DD-475
Praise the Sun!
The heliosphere is the vast bubble of solar wind, the stream of charged particles emitted by the Sun, that extends outward past the planets until it meets the interstellar medium at the heliopause. It deflects much of the galactic cosmic radiation that would otherwise reach the inner solar system. The footage, credited to thegalacticvoid, shows an animation of the heliosphere.
DID YOUKNOW?Go for a SpinDD-474
Go for a Spin
SpinLaunch is a U.S. company developing a kinetic launch system: a vacuum-sealed centrifuge spins a payload on an arm to hypersonic speed and releases it upward, aiming to cut fuel use and cost. A small rocket stage would still be needed to reach orbit. It has run suborbital test flights from a smaller accelerator in New Mexico. The footage, credited to SpinLaunch, shows a test launch.
DID YOUKNOW?Black Hole BinaryDD-464
Black Hole Binary
A supermassive black hole binary forms after two galaxies merge and their central black holes sink toward the middle and orbit each other. They spiral closer through interactions with surrounding stars and gas and, finally, by emitting gravitational waves, before merging into one more massive black hole. The footage, credited to astropodis, shows a simulation of two black holes orbiting.
DID YOUKNOW?Proton-MDD-451
Proton-M
Proton-M is a Russian heavy-lift rocket. On July 2, 2013, one carrying three GLONASS navigation satellites veered off course right after liftoff from Baikonur and crashed; investigators found angular velocity sensors had been installed upside down. On May 16, 2015, another Proton-M failed during ascent and lost Mexico's MexSat-1 satellite. The footage shows the 2013 crash.
DID YOUKNOW?Full-FlowDD-446
Full-Flow
Full-flow staged combustion is a rocket engine cycle in which all of the fuel and all of the oxidizer pass through separate preburners that drive the turbopumps, then enter the main combustion chamber as hot gases. Splitting the flow lets the turbines run cooler and supports high chamber pressures. SpaceX's Raptor was the first such engine to fly. The footage shows engine test firings.
DID YOUKNOW?striking!DD-393
striking!
A 2020 study estimated that about 17 meteorites, totaling some 6,100 a year, reach Earth's surface daily, most in oceans or remote areas. Over about 4.5 billion years, impacts number in the billions. Famous craters include Chicxulub in Mexico, linked to the extinction of the non-avian dinosaurs about 66 million years ago, and Meteor Crater (Barringer Crater) in Arizona, about 50,000 years old. The footage shows an animated Earth with impact points.
DID YOUKNOW?Lunar TopographyDD-385
Lunar Topography
The Moon's craters were made by impacts of asteroids, comets and meteoroids over billions of years. Many large basins date to an early period of heavy bombardment, sometimes called the Late Heavy Bombardment, often placed about 4.1 to 3.8 billion years ago. The South Pole-Aitken Basin, about 2,500 kilometers across, is the largest. Without air or water, there is little erosion to wear them away. The footage shows close-up views of the lunar surface.
DID YOUKNOW?433 ErosDD-380
433 Eros
433 Eros is a near-Earth asteroid about 34 by 11 by 11 kilometers, discovered in 1898. NASA's NEAR Shoemaker spacecraft orbited it in 2000 and landed on it on February 12, 2001, the first landing on an asteroid. Manhattan is about 21.6 kilometers (13.4 miles) long, so Eros would overhang it. The footage shows an animated Eros hovering over a landscape for scale.
DID YOUKNOW?Delta IV HeavyDD-374
Delta IV Heavy
The Delta IV Heavy, built by United Launch Alliance, used three Common Booster Cores burning liquid hydrogen and oxygen. It could lift about 28,800 kilograms to low Earth orbit or about 14,200 kilograms to geostationary transfer orbit, and launched spy satellites, the Orion test flight and the Parker Solar Probe. It first flew in 2004 and made its final flight on April 9, 2024. The footage shows a Delta IV Heavy launch.
DID YOUKNOW?ThrustDD-360
Thrust
NASA's Space Shuttle, flown from 1981 to 2011, launched on two solid rocket boosters and three main engines. The Reel puts total liftoff thrust at about 7.8 million pounds: about 6.6 million from the boosters and 1.2 million from the main engines. The boosters burned for about two minutes before separating. The footage shows rocket launch imagery.
DID YOUKNOW?The Hyperion SledDD-355
The Hyperion Sled
Philip Bono, an engineer at Douglas Aircraft, proposed Hyperion in the 1960s as a reusable single-stage launcher. It would ride a rocket-powered sled along a long track to gain speed horizontally, saving propellant before climbing to orbit. It was never built. The footage shows rocket sled tests and an animation of a launch.
DID YOUKNOW?The Strings of FateDD-319
The Strings of Fate
String theory proposes that particles are tiny vibrating strings. Superstring theories require 10 spacetime dimensions, and M-theory, which links them, requires 11. Beyond the three dimensions of space and one of time, the extra dimensions are thought to be compactified, curled up at scales far too small to detect. String theory remains untested by experiment. The footage is an animated tesseract and other higher-dimensional shapes.
DID YOUKNOW?Type IDD-263
Type I
The Kardashev scale was proposed in 1964 by the Soviet astronomer Nikolai Kardashev to classify civilizations by energy use. A Type I civilization uses energy on the scale of all that reaches its home planet from its star, about 10^16 to 10^17 watts for Earth; Type II uses the full output of its star; Type III that of a galaxy. Carl Sagan suggested a sliding scale, on which humanity rates about 0.7. The footage shows animated planets and energy imagery, with the presenter.
DID YOUKNOW?Not the Space ForceDD-259
Not the Space Force
NASA, the National Aeronautics and Space Administration, is the U.S. civilian space agency, established on July 29, 1958. Its Apollo program landed 12 astronauts on the Moon between 1969 and 1972. It also runs robotic missions such as the Mars rovers, Earth-observing satellites and space telescopes including Hubble and, with partners, the James Webb Space Telescope. Its Artemis program aims to return astronauts to the Moon. The U.S. Space Force, by contrast, is a military branch founded in 2019. The footage shows NASA missions and facilities, with the presenter.
DID YOUKNOW?Look Up, Can You See It?DD-258
Look Up, Can You See It?
The International Space Station is a modular space station in low Earth orbit, at about 400 km (250 miles), circling Earth about every 90 minutes. Its first module launched in 1998, and it has been continuously crewed since November 2000. It is a joint project of NASA, Roscosmos, the European Space Agency, JAXA and the Canadian Space Agency, and serves as a microgravity laboratory. Because it is large and reflective, it is often visible from the ground as a bright moving point shortly after sunset or before sunrise. The footage shows the station and its crews, with the presenter.
DID YOUKNOW?It IS Rocket ScienceDD-257
It IS Rocket Science
The Space Shuttle was NASA's partly reusable launch system, flown from April 12, 1981, to July 21, 2011. Each stack combined a winged orbiter, a large external fuel tank and two solid rocket boosters; the orbiter landed like a glider and was reused. The five orbiters that flew in space, Columbia, Challenger, Discovery, Atlantis and Endeavour, made 135 missions, launching satellites and probes, deploying and servicing the Hubble Space Telescope, and building much of the International Space Station. Two orbiters and 14 astronauts were lost, in the Challenger (1986) and Columbia (2003) disasters. The footage shows shuttle launches, with the presenter.
DID YOUKNOW?Keep Looking, What Do You See?DD-256
Keep Looking, What Do You See?
The Hubble Space Telescope, a NASA project with the European Space Agency, was launched aboard Space Shuttle Discovery on April 24, 1990. A flaw in its main mirror was corrected by astronauts in 1993, and five servicing missions kept it working. Orbiting above the atmosphere, it takes sharp images free of atmospheric blur. Its observations helped pin down the age of the universe at about 13.8 billion years, supported the discovery of the universe's accelerating expansion and dark energy, and produced views of distant galaxies and nebulae. The footage shows Hubble in orbit and its images, with the presenter.
DID YOUKNOW?Eyes in the SkyDD-255
Eyes in the Sky
Thousands of active satellites orbit Earth. Communications satellites relay TV, internet and phone signals; navigation constellations such as the U.S. GPS let receivers calculate their position; weather satellites track clouds and storms; and Earth-observation and science satellites study the climate, land, oceans and space weather. The first artificial satellite, Sputnik 1, was launched in 1957. The footage shows animated Earth and satellites, with the presenter.
DID YOUKNOW?MercuryDD-133
Mercury
Mercury, the closest planet to the Sun, has almost no atmosphere (only a thin exosphere) to trap heat. Its daytime surface reaches about 430 °C (800 °F), hot enough to melt lead, while nights fall to about -180 °C (-290 °F). That is the largest day-night swing of any planet. Its slow rotation also stretches each day: a solar day lasts about 176 Earth days. Despite the heat, radar and the MESSENGER spacecraft found water ice in permanently shadowed craters near the poles. The footage shows images of Mercury and the Sun, with the presenter.
DID YOUKNOW?VenusDD-132
Venus
Venus rotates in the opposite direction to most planets, a retrograde rotation, so the Sun would rise in the west. It is also the slowest-spinning major planet: one rotation relative to the stars (a sidereal day) takes about 243 Earth days, longer than its 225-day orbit around the Sun. Because of the combined motions, a solar day on Venus, sunrise to sunrise, lasts about 117 Earth days. The cause of the retrograde spin is unsettled; ideas include a giant impact and tidal effects of its thick atmosphere. The footage shows images of Venus, with the presenter.
DID YOUKNOW?EarthDD-131
Earth
Earth is not a perfect sphere but an oblate spheroid: its rotation flattens it at the poles and makes it bulge at the equator. The equatorial diameter is about 43 km greater than the polar diameter. Because of the bulge, the point on Earth's surface farthest from its center is the summit of Chimborazo in Ecuador, not Everest. The footage shows Earth from space, with the presenter.
DID YOUKNOW?MarsDD-130
Mars
Olympus Mons on Mars is a huge shield volcano, among the tallest known in the solar system. Its summit stands about 21.9 km (72,000 ft) above the Martian datum, roughly 2.5 times Mount Everest's height above sea level, and it's about 600 km wide. It formed through long-lived eruptions of fluid lava. Mars's low gravity and lack of plate tectonics let lava pile up over one hotspot. Some lava flows are geologically young, so it may not be entirely extinct. The footage shows renderings of Mars and Olympus Mons, with the presenter.
DID YOUKNOW?JupiterDD-129
Jupiter
The Great Red Spot is a giant anticyclone in Jupiter's southern hemisphere, wider than Earth though it has been shrinking. It has been observed continuously since 1878, with records back to 1831. A similar spot was seen from 1665 to 1713; if it was the same storm, it would be over 350 years old, but a 2024 study suggested it wasn't. Jupiter also has the strongest planetary magnetic field in the solar system, which traps intense radiation belts that spacecraft must be shielded against. The footage shows renderings and images of Jupiter, with the presenter.
DID YOUKNOW?SaturnDD-128
Saturn
The Cassini Division is a roughly 4,800 km wide region between Saturn's A and B rings, discovered by Giovanni Domenico Cassini in 1675. It looks empty from Earth but contains thinner, sparser ring material. It's largely cleared by a 2:1 orbital resonance with the moon Mimas. NASA's Cassini spacecraft orbited Saturn from 2004 until it was deliberately plunged into the planet in 2017, studying the rings in detail. The footage shows renderings of Saturn and its rings, with the presenter.
DID YOUKNOW?UranusDD-127
Uranus
Uranus, the seventh planet from the Sun, is an ice giant whose rotation axis is tilted about 98 degrees (97.77°) relative to its orbit, so it essentially spins on its side. Over its 84-year orbit, each pole spends about 42 years in sunlight and then 42 years in darkness, giving it the most extreme seasons of any planet. The cause of the tilt isn't settled; a leading idea is one or more giant impacts early in the solar system's history. Voyager 2 is the only spacecraft to have visited, flying past in 1986. The footage shows renderings of Uranus and its rings, with the presenter.
DID YOUKNOW?NeptuneDD-126
Neptune
Neptune, the eighth planet, has the strongest sustained winds measured on any planet in the solar system, up to about 2,100 km/h (around 1,300 mph). When Voyager 2 flew past in 1989, it photographed a huge storm in the southern hemisphere, the Great Dark Spot, comparable in scale to Jupiter's Great Red Spot. Unlike Jupiter's long-lived storm, Neptune's dark spots aren't permanent; later Hubble images showed that spot gone and new ones forming. Bright, high clouds of methane ice also streak across the planet. The footage shows Voyager-style images of Neptune and clouds, with the presenter.
DID YOUKNOW?PlutoDD-125
Pluto
Clyde Tombaugh discovered Pluto in 1930 at Lowell Observatory, and it was counted as the ninth planet until August 24, 2006, when the International Astronomical Union defined 'planet' in a way that made Pluto a dwarf planet. NASA's New Horizons flew past in July 2015 and photographed a bright, heart-shaped region named Tombaugh Regio after its discoverer. The heart's western lobe, Sputnik Planitia, is a vast basin of nitrogen, carbon monoxide and methane ices; the eastern lobe is uplands coated with nitrogen ice. The footage shows New Horizons images of Pluto, the observatory dome and icy terrain, with the presenter.
DID YOUKNOW?Quasi-StellarDD-106
Quasi-Stellar
A quasar is an extremely luminous active galactic nucleus: a supermassive black hole at the center of a galaxy surrounded by a gaseous accretion disk. As gas falls toward the black hole it heats up and releases enormous energy across the electromagnetic spectrum, often outshining the host galaxy. The name comes from 'quasi-stellar radio source', because the first ones found in the 1950s and 60s looked like faint stars. Maarten Schmidt identified the redshift of quasar 3C 273 in 1963, showing quasars are very distant. The footage shows renderings of galaxies, accretion disks and black holes.
DID YOUKNOW?Coronal Mass EjectionDD-091
Coronal Mass Ejection
A coronal mass ejection (CME) is a large expulsion of plasma and magnetic field from the Sun's corona. According to NOAA's Space Weather Prediction Center, a CME can eject billions of tons of coronal material carrying an embedded magnetic field. When one reaches Earth it can trigger a geomagnetic storm, which can disrupt radio communication and satellites and push auroras to lower latitudes than usual. Wikipedia gives an average mass of about 1.6 × 10^12 kg, noting that estimates are lower limits. The footage shows solar imagery, Earth's magnetic field, city lights from orbit and auroras, with the presenter.
DID YOUKNOW?Event HorizonDD-089
Event Horizon
A black hole's event horizon is the boundary beyond which nothing, not even light, can escape. Anything that crosses it moves inevitably toward the center, where general relativity predicts a singularity. The horizon results from extreme spacetime curvature caused by mass packed into a small region, and it marks the point of no return.
DID YOUKNOW?NebulaDD-087
Nebula
Nebulae are huge clouds of gas and dust in space. Types include emission nebulae, which glow; reflection nebulae, which scatter starlight; and dark nebulae, which block light behind them. Stars form when dense regions of molecular clouds collapse under gravity into protostars surrounded by disks. Radiation and winds from young, massive stars then shape the surrounding gas and make it glow.