
Atomic clock confirms that Tokyo’s tallest tower is also its most futuristic.
As the tallest structure in Japan, the Tokyo Skytree provides unparalleled views of the city and its surroundings and the exhilaration of standing farther off the ground than anyone in the country who’s not in an airplane. But it turns out there’s something else you can add to what the Skytree offers: time acceleration.
In simplified terms, Einstein’s general theory of relativity holds that time moves more slowly where gravity is heavier, and faster where there’s less gravity. Under that logic, University of Tokyo quantum electronics professor Hidetoshi Katori wanted to see what’s happening with the flow of time at the Skytree’s 450-meter (1,476-foot)-high observation floor. Using an optical lattice clock (a kind of atomic clock accurate up to a one-second differential over 30 billion years), Katori and his research team took measurements and determined that time is indeed moving faster up in the observatory than it is at Tokyo street level.
For each second that passes on the surface, the researchers found that an extra five trillionths of a second have elapsed on the Skytree’s observation floor. Stretched out over the course of an entire day, that works out to an extra four billionths of a second.
Unfortunately, that time acceleration isn’t significant enough for us to take a quick ride in the Skytree’s elevator in order to get a head start on the weekend. However, Katori says he believes there can be practical applications of this knowledge, and considering that the very tip of the Skytree is 634 meters above the ground, it stands to reason that time is passing even more quickly there.
Sources: Kyodo via Hachima Kiko, Mainichi Shimbun, Nature Photonics
Top image: Pakutaso
● Want to hear about SoraNews24’s latest articles as soon as they’re published? Follow us on Facebook and Twitter!

Tokyo Skytree’s disappointing attendance: 6.19 million visitors
Evangelion taking over Tokyo Skytree just in time for Christmas
Gigantic Evangelion Spear of Longinus appears stabbed in the ground at the Tokyo Skytree【Photos】
No, the Tokyo Skytree wasn’t lit in colors of Ukraine for solidarity…but another landmark is
Tokyo Skytree to light up in Demon Slayer character colors as part of tie-up event with anime hit
Japan’s 5.3 million beautiful Hitachi Nemophila flowers are now in full bloom[Photos]
Japanese government creates new word for cruelly hot summer days
7-Eleven Japan releases Uji matcha smoothies… but only at select locations
Japanese-style afternoon tea in this Japanese manor house outside downtown Tokyo is something special
Here’s the best spot to take in a panoramic view at “the most beautiful Starbucks in the world”
Mr. Sato shares his own secret Ministop hack to help save the ailing convenience store
Soaking in glimmering water and the essence of prehistoric plants at a Hokkaido hot spring
Immerse yourself in TeamLab Yoro Valley’s outdoor nighttime art exhibition in Chiba’s wilderness
Move aside, convenience store egg sando – there’s a better version of the iconic sandwich in Japan
The 10 best day trips from downtown Tokyo【Survey】
Brand-new Pokémon manhole covers coming to help the recovery of a disaster-stricken part of Japan
Japan’s awesomely beautiful Alpen Route snow corridor is now open
Wisteria season starts early with blooming of Japan’s Great Wisteria in its beautiful garden
Injuries on stairs in Tokyo highlight an overlooked design flaw
Japan’s popular bead bonsai kit is as beautiful as it is gruelling to make
Japan’s best conveyor belt sushi restaurant of seven years ago has now, finally, come to Tokyo
Final version of Sanrio: Beginning of Kawaii exhibition opens in Tokyo[Photos]
Japan has new rules for bicycle riders, and these 14 things could get you a fine or a court date
Japan reportedly adding Japanese language skill requirement to most common foreigner work visa
Pokémon and Ikea Japan cross over into each other’s worlds with collaboration events
Japan now has a special desk for people who work at home with a pet cat[Photos]
Famous Tokyo cherry blossom spot installs view-blocking screens to fight overcrowding[Video]
Uniqlo announces new T-shirts for One Piece, Naruto and more for manga publisher’s 100th birthday
Krispy Kreme releases Super Mario doughnuts in Japan for a limited time
Survey asks foreign tourists what bothered them in Japan, more than half gave same answer
Japan’s human washing machines will go on sale to general public, demos to be held in Tokyo
Starbucks Japan releases new drinkware and goods for Valentine’s Day
We deeply regret going into this tunnel on our walk in the mountains of Japan
Starbucks Japan releases new sakura goods and drinkware for cherry blossom season 2026
Studio Ghibli releases Kodama forest spirits from Princess Mononoke to light up your home
Japan’s newest Shinkansen has no seats…or passengers [Video]
Major Japanese hotel chain says reservations via overseas booking sites may not be valid
Put sesame oil in your coffee? Japanese maker says it’s the best way to start your day【Taste test】
No more using real katana for tourism activities, Japan’s National Police Agency says
History’s highest sumo wrestling and geisha dance to take place at Tokyo Skytree observation deck
Lightning storm photos of the Skytree show the Tokyo symbol in a whole new light【Photos】
Sakura Skytree photos take Tokyo’s breath away, give kick-start to cherry blossom season【Photos】
Is this Tokyo, or Final Fantasy? Rainy season night makes for incredible Skytree view【Photos】
Tokyo Tower, Skytree, lit in colors of American flag as Donald Trump arrives in Japan
Tokyo Skytree to light up in Pokémon colors for summer-long art event!
Check out the one-month electric bills for Tokyo Tower, Skytree and more!
New Pokémon Center megastore set to open at Tokyo Skytree this summer!
Beautiful forest-style Studio Ghibli specialty shop reopens at Tokyo Skytree this summer
Tokyo Skytree turns pink for the cherry blossom season
Amazing circular rainbow spotted in Tokyo【Video】
Japanese candy artisan opens new store below Tokyo Skytree with exclusive sweets
New Edo Goldfish Wonderland to open at Tokyo Skytree this summer for a limited time
Godzilla, Evangelion, Ultraman, and Kamen Rider have formed a giant robot in tokusatsu clip【Vid】