A Rocky World with Approximately the Same Surface Gravity as Earth


In a breakthrough discovery, NASA‘s Hubble Space Telescope has measured the size of the nearest transiting Earth-sized planet. This planet, named LTT 1445Ac, is located just 40 light-years from Earth and is the closest Earth-sized planet yet found orbiting a Sun-like star.

LTT 1445Ac: A Rocky World with Approximately the Same Surface Gravity as Earth

The Hubble observations show that LTT 1445Ac is only 1.07 times Earth’s diameter, making it a rocky world with approximately the same surface gravity as Earth. However, at a surface temperature of roughly 260 degrees Celsius (500 degrees Fahrenheit), it is too hot for life as we know it.

The Discovery of LTT 1445Ac

LTT 1445Ac was first discovered in 2022 by NASA’s Transiting Exoplanet Survey Satellite (TESS). TESS is a space telescope designed to search for exoplanets, which are planets that orbit stars other than our Sun.

LTT 1445Ac, orbiting a star similar to our Sun, has been the subject of intense scrutiny since its discovery in 2022. The planet’s close proximity to Earth and its Earth-like size have fueled speculation about its potential for habitability.

The measurement of LTT 1445Ac’s size has paved the way for future studies into its atmosphere and potential for habitability. With the launch of the James Webb Space Telescope (JWST) in 2021, scientists hope to gain a deeper understanding of this intriguing exoplanet, including its composition and the presence of any potential biosignatures.

The Importance of Measuring Exoplanet Sizes

Measuring the sizes of exoplanets is important because it helps us to understand their composition and potential for habitability. Rocky planets like Earth are more likely to be habitable than gas giants like Jupiter.

Hubble has played a critical role in the field of exoplanet research. Since its launch in 1990, Hubble has observed thousands of exoplanets and has helped to characterize their sizes, masses, and atmospheres.

Despite the setback, the discovery of LTT 1445Ac remains a significant milestone in exoplanet research. It highlights the capabilities of Hubble, an aging yet still-powerful telescope, and underscores the importance of continuous efforts to explore the cosmos.

The Future of Exoplanet Research

The discovery of LTT 1445Ac is a major milestone in the search for habitable exoplanets. With the help of future telescopes, such as the James Webb Space Telescope, scientists hope to find Earth-sized planets that could support life.

Countries Involved

  • United States: NASA, the US space agency, is responsible for the Hubble and James Webb Space Telescopes. The US has been a leader in exoplanet research for many decades.
  • Europe: The European Space Agency (ESA) is a partner in the Hubble Space Telescope project. ESA is also building the James Webb Space Telescope.
  • Canada: Canada is a partner in the James Webb Space Telescope project. Canadian scientists are playing a leading role in exoplanet research.


The discovery of LTT 1445Ac is a significant step forward in our understanding of exoplanets. With the help of future telescopes, we may one day find an Earth-sized planet that is truly habitable and the upcoming investigations with JWST represent a new era in exoplanet research, bringing us closer to unraveling the mysteries of these distant worlds and the possibility of life beyond Earth.

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