Instagram story viewer> @sciencefacts_scf> Posts
Science Facts(@sciencefacts_scf)'s profile avatar HD Profile

Science Facts

@sciencefacts_scf

133
followers
1
following
We bring you the science in facts. A "did you know?" science fact series.
POSTS STORIES REELS TAGGED
Astronauts return from orbit measurably taller, and it's a medical problem rather than a novelty. Your intervertebral discs absorb fluid overnight and get compressed under your own weight through the day, so you're up to two centimetres shorter by evening than you were at breakfast. Remove gravity and the compression never comes. Astronauts on long-duration missions gain roughly 3% in height several centimetres as the discs expand unopposed. The consequences aren't cosmetic. The surrounding muscles weaken without load, spinal stabiliser muscles atrophy, and NASA has documented a substantially elevated rate of herniated discs in astronauts during the first year after return, with one study finding several times the expected rate. That's why crew exercise protocols include treadmill running in a harness that pulls the body downward, simulating spinal loading that would otherwise vanish entirely, plus targeted core rehabilitation after landing. (Johnston et al., 2010, Aviation, Space, and Environmental Medicine; NASA Human Research Program) Astronauts come home taller and with a real risk of disc injury. Height, bone density, vision, immune function. Which spaceflight effect do you think is still most underestimated? #SpaceMedicine #HumanBiology #NASA #Spaceflight by @sciencefacts_scf
1
2 months ago
Download
There are 37 trillion of you, working at once and none of them know you exist. A 2013 study estimated your body holds about 37 trillion cells. But the number isn't the strange part it's the coordination. Each cell runs its own chemistry, makes its own repairs, and lives its own life, with no awareness of "you." Yet all 37 trillion act in concert to produce a single person who can read this sentence. Nobody fully understands how that unity emerges from the crowd. (Bianconi et al., 2013, Annals of Human Biology) #sciencefacts #biology #humanbody #cells #cellbiology by @sciencefacts_scf
1
2 months ago
Download
Ordinary supernovae can't make gold. In 2017 we watched what does. Caption: Stars fuse their way up to iron and stop past that, fusion consumes energy rather than releasing it. Elements heavier than iron require rapid neutron capture, where nuclei absorb neutrons faster than they can decay, and that demands a neutron flux so extreme it was unclear for decades where in nature it actually occurred. On 17 August 2017, LIGO and Virgo detected gravitational waves from two neutron stars merging 130 million light years away, and roughly seventy observatories caught the afterglow across the electromagnetic spectrum. The light curve matched predictions for a kilonova powered by the radioactive decay of freshly forged heavy elements. Spectra indicated the production of gold and platinum totalling many times Earth's mass, in an event lasting seconds. Neutron star mergers are now the leading source of the heaviest elements, though how much other channels contribute remains open. (Abbott et al., 2017, PRL; Pian et al., 2017, Nature) The gold in your ring was likely forged by two colliding dead stars. One event, seventy observatories, days of notice. What would you have pointed at it? #Astrophysics #GravitationalWaves #Nucleosynthesis #LIGO by @sciencefacts_scf
1
2 months ago
Download
Everything you think, remember, and decide runs on less power than a dim lightbulb. Your brain is about 2% of your body weight but burns roughly 20% of your energy around 20 watts, less than a household bulb. On that tiny budget it runs your senses, memory, movement, and every thought you've ever had. A supercomputer draws millions of watts to imitate a fraction of what your brain does, and still falls short. How it achieves so much on so little remains one of biology's open questions. (Metabolic physiology estimates) #sciencefacts #biology #neuroscience #brain #humanbody by @sciencefacts_scf
1
2 months ago
Download
Your stomach lining is made of the same protein it digests. It survives by rebuilding faster than the acid destroys it. Gastric acid runs around pH 1.5–2, and the stomach wall has no special immunity to it it's built from the same proteins as everything else in the digestive tract. Survival is a matter of speed and shielding. A layer of mucus laced with bicarbonate neutralises acid at the surface, and beneath it, the epithelial lining replaces itself entirely in roughly three to five days, among the fastest renewing tissues in the body. Skin takes about a month by comparison. Stem cells at the base of the gastric pits divide continuously, pushing fresh cells upward to replace those stripped away above. This isn't maintenance, it's active defence: any damaged cell left in place is an opening for acid to reach deeper tissue. When either mechanism fails mucus barrier or renewal rate you get an ulcer. Your stomach lining renews itself roughly ten times faster than your skin. Which other organ do you think is quietly rebuilding itself faster than you'd guess? #HumanBiology #Digestion #CellBiology #Gastroenterology by @sciencefacts_scf
1
2 months ago
Download
There are 37 trillion of you, working at once and none of them know you exist. A 2013 study estimated your body holds about 37 trillion cells. But the number isn't the strange part it's the coordination. Each cell runs its own chemistry, makes its own repairs, and lives its own life, with no awareness of "you." Yet all 37 trillion act in concert to produce a single person who can read this sentence. Nobody fully understands how that unity emerges from the crowd. (Bianconi et al., 2013, Annals of Human Biology) #sciencefacts #biology #humanbody #cells #cellbiology by @sciencefacts_scf
1
2 months ago
Download
The "90% bacteria" claim was wrong. The corrected version is stranger. The bacteria-to-human cell ratio is roughly 1:1 about 38 trillion to 30 trillion not the 10:1 that circulated for decades on the strength of a 1972 estimate nobody had verified. Count genes instead of cells and the picture inverts hard. The human genome carries around 20,000 protein-coding genes. The collective genome of your gut microbiome runs to several million distinct genes, outnumbering yours by something like 100:1. Those genes aren't idle. They break down dietary fibre your own enzymes cannot touch, synthesise certain vitamins, and communicate continuously with your immune system. Some researchers describe the result as a superorganism: one human genome operating in partnership with a vastly more diverse microbial one. The myth needed correcting, but what replaced it is harder to hold onto. (Sender, Fuchs & Milo, 2016, PLOS Biology; Qin et al., 2010, Nature) Cell for cell, roughly half. Gene for gene, badly outnumbered. Gut bacteria fermenting fibre produce short-chain fatty acids, and butyrate is the primary energy source for the cells lining your colon. Part of your gut runs on microbial waste products. If most of the genes operating in your body aren't yours, where does "you" end? #Microbiome #HumanBiology #Genetics #GutHealth by @sciencefacts_scf
1
2 months ago
Download
Your two lungs aren't the same size and the reason is sitting right between them. Your left lung is smaller than your right, with only two lobes instead of three. The reason is your heart. It sits slightly left of center, and the left lung has a scoop carved out of its edge the cardiac notch to make room for it. Your lungs were shaped around your heart before you were born. #sciencefacts #biology #humanbody #anatomy #medicine #learnontiktok #scitok by @sciencefacts_scf
1
2 months ago
Download
A fully dark adapted eye can spot a candle from about 2.6 kilometres and that number is a real measurement, not the myth you've heard. You've probably seen the claim that the human eye can see a candle from 30 miles. It isn't true, and it doesn't come from any study. In 2015, Krisciunas and Carona did the calculation properly, treating a candle flame as a light source of known output and comparing it to the faintest star a dark-adapted observer can detect. The answer is roughly 2.6 kilometres about 1.6 miles. Still remarkable. Individual rod cells genuinely respond to single photons, established by Baylor's electrophysiology in 1979, and a 2016 experiment found that people guessing whether a single photon had been fired were correct 51.6% of the time against a 50% baseline. That's the edge of perception, not comfortable detection. Full dark adaptation takes 30–45 minutes as rhodopsin regenerates, and a single glance at a phone screen resets it. (Krisciunas & Carona, 2015; Baylor et al., 1979; Tinsley et al., 2016, Nature Communications) Not 30 miles. 1.6 miles and that's a measured number. Have you ever been somewhere with genuinely no light pollution? What changed in your vision over the first half hour? #HumanBiology #Vision #Neuroscience #DarkAdaptation by @sciencefacts_scf
1
2 months ago
Download
We can estimate the number of stars in the universe more confidently than the number of sand grains on Earth. It sounds backwards until you consider the method. Sand sits across beaches, deserts, riverbeds, and seafloors, at wildly varying depths and grain sizes, in places nobody can survey. Any total is an extrapolation from a handful of samples with enormous uncertainty. Stars are easier, oddly, because they radiate. Measure a galaxy's total light output, divide by the average luminosity of a star, and you get a population estimate; count galaxies in a deep survey field, scale to the whole sky, and multiply. The result roughly 10²² to 10²⁴ stars in the observable universe carries real uncertainty, but it comes from a systematic, repeatable, checkable procedure. The famous comparison isn't really about which number wins. It's a contrast between a quantity we have a method for and one we mostly don't. We can estimate the universe's stars better than Earth's sand. What else that feels uncountable might actually have a clean estimation method nobody has applied yet? #Astronomy #Cosmology #Universe #ScientificMethod by @sciencefacts_scf
1
2 months ago
Download
Astronomers measured the actual colour of a planet 64 light-years away. It's cobalt blue, and the reason is molten glass. HD 189733b is a hot Jupiter orbiting its star every 2.2 days, with winds estimated in the thousands of kilometres per hour and silicate particles in its atmosphere that condense into what amounts to sideways-driven glass. In 2013, astronomers used Hubble to watch the planet pass behind its star and measured how much the total light in visible wavelengths dropped. That difference is the planet's own reflected light, and it revealed a deep cobalt blue. The colour resembles Earth's oceans from orbit and arises from something completely different: not water, but silicate particles scattering blue light in a superheated atmosphere. The measurement mattered because it moved exoplanet science from inferring appearance through models to measuring it a planet's colour, determined across 64 light-years. (Evans et al., 2013, ApJL) This exoplanet's true colour was measured. Deep cobalt blue. Lava worlds, ice giants, planets locked with one face to their star. Which would you most want measured next, and what colour would you guess? #Exoplanets #Hubble #Astronomy #HotJupiter by @sciencefacts_scf
1
2 months ago
Download
A moon 500 kilometres across is venting the exact chemistry that may have started life on Earth. Enceladus fires plumes of water from fractures at its south pole, and Cassini flew through them. Beyond water and ice, the instruments found molecular hydrogen a strong indicator that hot rock is reacting with water on the floor of a subsurface ocean, the signature of hydrothermal vents. On Earth, such vents are a leading candidate for where life began: they supply a continuous chemical energy gradient in total darkness, no sunlight needed. Finding the same signature at Enceladus means a moon far outside the Sun's habitable zone may host the chemical conditions for microbial life. Later analysis of the plume data has also turned up phosphates and complex organic molecules. That's why a body smaller than Spain has become one of the highest priority targets in the search for life. (Waite et al., 2017, Science; Postberg et al., 2023, Nature) This tiny moon is venting the same chemistry that may have started life on Earth. A future mission could fly through the plume and sample the ocean without ever landing. What would you have it look for first? #Enceladus #Astrobiology #Cassini #OceanWorlds by @sciencefacts_scf
1
2 months ago
Download

Download All

Save the photos and videos currently loaded on this page.

0Photos
0Videos
Ready to download 0 / 0

Keep this tab open until your download is ready.
back to up