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Water-World Exoplanet

An ocean planet, ocean world, water world, aquaplanet or panthalassic planet is a type of terrestrial planet that contains a substantial amount of water either at its surface or subsurface.

Earth is the only astronomical object known to have bodies of liquid water on its surface, although several exoplanets have been found with the right conditions to support liquid water. For exoplanets, current technology cannot directly observe liquid surface water, so atmospheric water vapor may be used as a proxy. The characteristics of ocean worlds—or ocean planets—provide clues to their history, and the formation and evolution of the Solar System as a whole. Of additional interest is their potential to originate and host life.

Water worlds are of extreme interest to astrobiologists for their potential to develop life and sustain biological activity over geological timescales. The five best established water worlds in the Solar System include Europa, Enceladus, Ganymede, and Callisto. A host of other bodies in the outer Solar System are inferred by a single type of observation or by theoretical modeling to have subsurface oceans, and these include: Dione, Pluto, Triton, and Ceres, as well as Mimas, Eris, and Oberon. read more

This picture, taken by Hubble’s Advanced Camera for Surveys, shows NGC 4696, the largest galaxy in the Centaurus Cluster.

The huge dust lane, around 30 000 light-years across, that sweeps across the face of the galaxy makes NGC 4696 look different from most other elliptical galaxies. Viewed at certain wavelengths, strange thin filaments of ionised hydrogen are visible within it. In this picture, these structures are visible as a subtle marbling effect across the galaxy’s bright centre.

Credit: ESA/Hubble and NASA

Against a stunning backdrop of thousands of galaxies, this odd-looking galaxy with the long streamer of stars appears to be racing through space, like a runaway pinwheel firework.

This picture of the galaxy UGC 10214 was taken by the Advanced Camera for Surveys (ACS), which was installed aboard the NASA/ESA Hubble Space Telescope in March (2002) during Servicing Mission 3B. Dubbed the ‘Tadpole’, this spiral galaxy is unlike the textbook images of stately galaxies. Its distorted shape was caused by a small interloper, a very blue, compact, galaxy visible in the upper left corner of the more massive Tadpole. The Tadpole resides about 420 million light-years away in the constellation Draco.

Credit: NASA, Holland Ford (JHU), the ACS Science Team and ESA

The Spindle Galaxy (NGC 5866), a lenticular galaxy in the Draco constellation. This image shows that lenticular galaxies may retain a considerable amount of dust in their disk. There is little to no gas and thus they are considered deficient in interstellar matter.

Credit:

NASA, ESA, and The Hubble Heritage Team (STScI/AURA

NGC 3147

image credit:
Judy Schmidt

This rich galaxy cluster, catalogued as CL0024+17, is allowing astronomers to probe the distribution of dark matter in space. The blue streaks near the center of the image are the smeared images of very distant galaxies that are not part of the cluster. The distant galaxies appear distorted because their light is being bent and magnified by the powerful gravity of CL0024+17, an effect called gravitational lensing. Dark matter cannot be seen because it does not shine or reflect light. Astronomers can only detect its influence by how its gravity affects light. By mapping the distorted light created by gravitational lensing, astronomers can trace how dark matter is distributed in the cluster. While mapping the dark matter, astronomers found a dark-matter ring near the cluster’s center. The ring’s discovery is among the strongest evidence that dark matter exists. The Hubble observations were taken in November 2004 by the Advanced Camera for Surveys.

Credit:

NASA, ESA, M.J. Jee and H. Ford (Johns Hopkins University)

This rich galaxy cluster, catalogued as CL0024+17, is allowing astronomers to probe the distribution of dark matter in space. The blue streaks near the center of the image are the smeared images of very distant galaxies that are not part of the cluster. The distant galaxies appear distorted because their light is being bent and magnified by the powerful gravity of CL0024+17, an effect called gravitational lensing. Dark matter cannot be seen because it does not shine or reflect light. Astronomers can only detect its influence by how its gravity affects light. By mapping the distorted light created by gravitational lensing, astronomers can trace how dark matter is distributed in the cluster. While mapping the dark matter, astronomers found a dark-matter ring near the cluster’s center. The ring’s discovery is among the strongest evidence that dark matter exists. The Hubble observations were taken in November 2004 by the Advanced Camera for Surveys.

Credit:

NASA, ESA, M.J. Jee and H. Ford (Johns Hopkins University)

The NASA/ESA Hubble Space Telescope usually works as a solo artist to capture awe-inspiring images of the distant Universe. For this picture, though, Hubble had a helping hand from the subject of the image, a galaxy cluster called LCDCS-0829, as the huge mass of the galaxies in the cluster acted like a giant magnifying glass. This strange effect is called gravitational lensing.

Credit: ESA/Hubble & NASA

The NASA/ESA Hubble Space Telescope usually works as a solo artist to capture awe-inspiring images of the distant Universe. For this picture, though, Hubble had a helping hand from the subject of the image, a galaxy cluster called LCDCS-0829, as the huge mass of the galaxies in the cluster acted like a giant magnifying glass. This strange effect is called gravitational lensing.

Credit: ESA/Hubble & NASA