London Daily

Focus on the big picture.
Tuesday, Jul 22, 2025

TOI 700 d: Earth-sized planet found relatively nearby

TOI 700 d: Earth-sized planet found relatively nearby

TESS discovers Earth-sized world orbiting a star about 100 light years from Earth, NASA announces.

NASA has announced that its planet hunter satellite TESS discovered an Earth-sized world within the habitable range of its star, which could allow the presence of liquid water.

The planet, named "TOI 700 d", is relatively close to Earth: only 100 light years away, NASA's Jet Propulsion Laboratory said on Monday during the annual American Astronomical Society meeting in Honolulu, Hawaii.

"TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars," said Paul Hertz, NASA astrophysics division director.

TESS initially misclassified the star, which meant the planets appeared larger and hotter than they actually are. But several amateur astronomers, including high school student Alton Spencer - who works with members of the TESS team - identified the error.

"When we corrected the star's parameters, the sizes of its planets dropped, and we realised the outermost one was about the size of Earth and in the habitable zone," said Emily Gilbert, a graduate student at the University of Chicago.

The discovery was later confirmed by the Spitzer Space Telescope.


Habitable zone


A few other similar planets have been discovered before, notably by the former Kepler Space Telescope, but this is the first one discovered by TESS, which was launched in 2018.

TESS stabilises on one area of the sky to detect whether objects - planets - pass in front of stars, which causes a temporary drop in the stars' luminosity. This allows TESS to infer the presence of a planet, its size and orbit.

Star TOI 700 is small, about 40 percent of the size of the Earth's Sun and only about half as hot.

TESS discovered three planets in orbit, named TOI 700 b, c and d. Only "d" is in the so-called habitable zone, not too far from and not too close to the star, where the temperature could allow the presence of liquid water.

It is about 20 percent larger than Earth and orbits its star in 37 days. Planet 700 d receives 86 percent of the energy that Earth receives from the Sun.

It remains to be seen what 700 d is made of. Researchers have generated models based on the size and type of star in order to predict 700 d's atmospheric composition and surface temperature.

In one simulation, NASA explained, the planet is covered in oceans with a "dense, carbon dioxide-dominated atmosphere similar to what scientists suspect surrounded Mars when it was young".

The planet is tidally locked to the star, meaning that one side always faces the star, as is the case with the Moon and Earth.

This synchronous rotation meant that, in another model, one side of the planet was constantly covered in clouds.

A third simulation predicted an all-land world, where winds flow from the planet's dark side to its light one.

Multiple astronomers will observe the planet with other instruments, in order to obtain new data that may match one of NASA's models.

Newsletter

Related Articles

0:00
0:00
Close
US Treasury Secretary Calls for Institutional Review of Federal Reserve Amid AI‑Driven Growth Expectations
UK Government Considers Dropping Demand for Apple Encryption Backdoor
Severe Flooding in South Korea Claims Lives Amid Ongoing Rescue Operations
Japanese Man Discovers Family Connection Through DNA Testing After Decades of Separation
Russia Signals Openness to Ukraine Peace Talks Amid Escalating Drone Warfare
Switzerland Implements Ban on Mammography Screening
Japanese Prime Minister Vows to Stay After Coalition Loses Upper House Majority
Pogacar Extends Dominance with Stage Fifteen Triumph at Tour de France
CEO Resigns Amid Controversy Over Relationship with HR Executive
Man Dies After Being Pulled Into MRI Machine Due to Metal Chain in New York Clinic
NVIDIA Achieves $4 Trillion Valuation Amid AI Demand
US Revokes Visas of Brazilian Corrupted Judges Amid Fake Bolsonaro Investigation
U.S. Congress Approves Rescissions Act Cutting Federal Funding for NPR and PBS
North Korea Restricts Foreign Tourist Access to New Seaside Resort
Brazil's Supreme Court Imposes Radical Restrictions on Former President Bolsonaro
Centrist Criticism of von der Leyen Resurfaces as she Survives EU Confidence Vote
Judge Criticizes DOJ Over Secrecy in Dropping Charges Against Gang Leader
Apple Closes $16.5 Billion Tax Dispute With Ireland
Von der Leyen Faces Setback Over €2 Trillion EU Budget Proposal
UK and Germany Collaborate on Global Military Equipment Sales
Trump Plans Over 10% Tariffs on African and Caribbean Nations
Flying Taxi CEO Reclaims Billionaire Status After Stock Surge
Epstein Files Deepen Republican Party Divide
Zuckerberg Faces $8 Billion Privacy Lawsuit From Meta Shareholders
FIFA Pressured to Rethink World Cup Calendar Due to Climate Change
SpaceX Nears $400 Billion Valuation With New Share Sale
Microsoft, US Lab to Use AI for Faster Nuclear Plant Licensing
Trump Walks Back Talk of Firing Fed Chair Jerome Powell
Zelensky Reshuffles Cabinet to Win Support at Home and in Washington
"Can You Hit Moscow?" Trump Asked Zelensky To Make Putin "Feel The Pain"
Irish Tech Worker Detained 100 days by US Authorities for Overstaying Visa
Dimon Warns on Fed Independence as Trump Administration Eyes Powell’s Succession
Church of England Removes 1991 Sexuality Guidelines from Clergy Selection
Superman Franchise Achieves Success with Latest Release
Hungary's Viktor Orban Rejects Agreements on Illegal Migration
Jeff Bezos Considers Purchasing Condé Nast as a Wedding Gift
Ghislaine Maxwell Says She’s Ready to Testify Before Congress on Epstein’s Criminal Empire
Bal des Pompiers: A Celebration of Community and Firefighter Culture in France
FBI Chief Kash Patel Denies Resignation Speculations Amid Epstein List Controversy
Air India Pilot’s Mental Health Records Under Scrutiny
Google Secures Windsurf AI Coding Team in $2.4 Billion Licence Deal
Jamie Dimon Warns Europe Is Losing Global Competitiveness and Flags Market Complacency
South African Police Minister Suspended Amid Organised Crime Allegations
Nvidia CEO Claims Chinese Military Reluctance to Use US AI Technology
Hong Kong Advances Digital Asset Strategy to Address Economic Challenges
Australia Rules Out Pre‑commitment of Troops, Reinforces Defence Posture Amid US‑China Tensions
Martha Wells Says Humanity Still Far from True Artificial Intelligence
Nvidia Becomes World’s First Four‑Trillion‑Dollar Company Amid AI Boom
U.S. Resumes Deportations to Third Countries After Supreme Court Ruling
Excavation Begins at Site of Mass Grave for Children at Former Irish Institution
×