Launch expected today: NASA's space telescope TESS
April 16, 2018
It might not be any bigger than your own refrigerator, but the TESS telescope will deliver the stuff of your wildest sci-fi fantasies: Earth-sized planets by the hundreds, and all in the next two years.
Its four cameras will monitor the 200,000 brightest stars in the vicinity of our sun, and, as with its predecessor telescope, Kepler, NASA scientists hope to find thousands of exoplanet candidates and to also confirm many of those as genuine.
About 300 of them, NASA estimates, may turn out to be about the size of our Earth.
For the first time, a scientific space probe will be launched by SpaceXImage: NASA
For astronomers it has been incredibly difficult to find exoplanets. In contrast to the stars they circle, they do not emit their own light or radiation and usually stay in the dark – almost impossible to detect with optical telescopes.
Furthermore, being in far away galaxies, they are unbelievably tiny from the perspective of Earth.
Such exoplanets only give a hint about their existence when they transit in front of their respective sun – from the perspective of Earth. They then cast a shadow and, for the time of their transit, the light emitted from their star gets somewhat dimmer.
The change in the light, the time it takes and the frequency with which such darkening occurs give astronomers important information that they can use to compute the characteristics of the planet: Its size its orbit and the distance from the planet.
Kepler has found throusands of exoplanets in a tiny section of Milky WayImage: picture alliance/dpa/epa/NASA/Ames/JPL-Caltech
The predecessor
NASA already used this physical method with its satellite Kepler between 2009 and 2013. The space probe observed 150,000 stars permanently and registered the slightest light fluctuations.
The satellite focused on a rather narrow section of the Milky Way located in the constellations of Cygnus, Lyra and Draco. At the end of the three-and-a-half year mission, Kepler had found more than 5,000 new candidates for exoplanets and actually confirmed the existence of half of them.
Due to technical problems, though, the Kepler mission later had to be refined. From 2014 on the spacecraft, under the mission name K2, searched through a larger section of the skies for different celestial bodies and events, such as supernova explosions, star systems, asteroids and comets.
Even then, Kepler still managed to find more exoplanets.
Now, Kepler is finally running out of fuel. This, in addition to other technical difficulties, is one of the reasons NASA opted to launch its successor, TESS.
Some of the planets Kepler found - in the solar system of the same nameImage: picture alliance/dpa/AP Photo/NASA/W. Stenzel
Small satellite, big expectations
This new satellite is expected to deliver data for two years. Its range of observation is 400 times larger than that of Kepler, and in contrast to its predecessor, TESS will not always be looking at the same section of the sky: It divides the heavens into 26 sectors. The craft will monitor each of those sectors for 27 days.
And TESS can do even more. Astronomers from universities as well as other partners have had the opportunity to list about 20,000 other celestial objects that TESS will take a look at - and about which it will deliver more up-to-date data.
At the end of this year, the European Space Agency (ESA) is planning to launch the Characterizing ExoPlanets Satellite (CHEOPS). It will be equipped with only one telescope and will be positioned in a sun-synchronous orbit, meaning that it will fly around the Earth in such a way that the sun – from the perspective of the space probe – is always in the same place.
Unlike TESS, the primary task for CHEOPS will not be to search for more exoplanets. Rather, it is going to look into already known exoplanets to measure them more precisely than ever before.
Earth-like planets and other celestial discoveries
Astronomers have found a new Earth-like planet in our neighboring solar system, Proxima Centauri. We take a look at this and other discoveries from Earth- and space-based telescopes.
Image: L. Calçada/ESO
Another planet Earth?
The European Southern Observatory (ESO) has discovered a third Earth-like planet orbiting the star Proxima Centauri, the closest star to our sun at four light years away. A planet is considered Earth-like if scientists suspect it provides conditions that could make life theoretically conceivable, such as a certain temperature range, gravity, an atmosphere and the possibility of water.
Image: L. Calçada/ESO
Discovery via the Very Large Telescope
Astronomers discovered the planet through the Very Large Telescope (VLT) in Chile's Atacama Desert. Proxima d is the lightest of the three planets discovered around our closest star. ESO researchers also discovered the somewhat larger Proxima b, but with a different telescope supported by the planet-search instrument HARPS.
Image: ESO/G. Lombardi
Spaceship Kepler: On the hunt for planets
Many Earth-like planets haven't been discovered by telescopes situated on Earth but by ones in space. Spaceship Kepler has been searching for Earth-like planets since 2009. Besides meeting the physical conditions, they must also consist of rock or metal compounds and have a solid surface, in contrast to gas giants like Jupiter and Saturn.
Image: NASA Ames/JPL-Caltech/T Pyle
A longer distance away
Exoplanet Kepler-186f is located 500 light years away from us, orbiting red dwarf Kepler-186. That small sun has only about 4% of the energy of our sun. Kepler-186f orbits Kepler-186 at a perfectly calibrated distance: Water would neither freeze nor evaporate on the planet, which is a precondition for life. But the question of whether there is water on Kepler-186f at all remains unanswered.
There are no detailed pictures of exoplanets, just artistic representations like this one of Kepler-186f. But not even a drawing exists of another recently discovered exoplanet, Kepler-438b, which orbits a sun-like star about 470 light years away from Earth and is just slightly larger than our planet. NASA published the discovery on January 6, 2014.
Image: picture-alliance/dpa
Ocean-covered giants?
This artist's drawing of Kepler-62e shows a planet covered by ocean. Scientists agree that Earth-like exoplanets most likely have large oceans. Kepler-62e can be found in the constellation of Lyra, located 1,200 light years away from us. And its mother star, Kepler-62, has yet another Earth-like planet ...
Image: NASA Ames/JPL-Caltech
The Kepler-62 brothers
... Kepler-62f, whose diameter is 1.4 times that of Earth. The Earth-like planet is located a bit further out in its solar system than its larger brother Kepler-62e, which is 1.61 times as big as Earth. Both may be suited for life. Researchers believe that the existence of rocks and water is plausible.
Image: NASA Ames/JPL-Caltech
Orbiting two suns
Even though Kepler-16b is located on the edge of an inhabitable zone, it probably doesn't host any life. This is a pity, because the planet orbits two suns — every morning and evening, its inhabitants would be able to observe two sunrises and sunsets! Too bad Kepler-16b is most likely a gas planet, composed of rock and ice — not good for beings needing to breathe fresh air.
Image: imago/UPI Photo
The Hubble Space Telescope offers many perspectives
The Pillars of Creation are located in the Eagle Nebula about 7,000 light years away. The joint ESA and NASA Hubble Space Telescope took new pictures of the formation through an infrared light spectrum. The pillars are home to numerous bright and young stars, including entire solar systems.
Image: NASA, ESA/Hubble and the Hubble Heritage Team
Lights on!
The same picture through visible light: more fog, but also more color. Dust and gas in the pillars are pierced by radiation originating from young stars. These new Hubble Telescope pictures enable researchers to monitor changes in the formation over a longer period of time.
Image: NASA, ESA/Hubble and the Hubble Heritage Team
A star is born
NGC 4102 is a LINER galaxy: a low-ionization nuclear emission-line region. This means it emits ionized radiation, like roughly one-third of all galaxies. At its center, there is a sun-burst region, where young stars seem to be born. It has a diameter of about 1,000 light years. Scientists don't understand the exact processes in the center yet.
Image: ESA/Hubble, NASA and S. Smartt (Queen's University Belfast)
A messier cluster
This cluster of stars, located in the northern part of the Hercules formation, is called Messier 92. On dark nights with clear skies, we can see it from Earth with bare eyes. The cloud includes roughly 330,000 stars, most of which consist of hydrogen and helium. Heavier elements like metals are rare.
Image: ESA/Hubble & NASA/Gilles Chapdelaine
The best view of Andromeda
The original version of this photo of the Andromeda Galaxy is 1.5 billion pixels in size — the most detailed picture ever taken of that galaxy. It includes 100 million stars and thousands of star clusters. To watch it in its entire beauty, one would need 600 HD-TV screens. The ends of the picture are 40,000 light years apart.
Image: NASA, ESA, J. Dalcanton (University of Washington, USA), B. F. Williams (University of Washington, USA), L. C. Johnson (University of Washington, USA), the PHAT team, and R. Gendler
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A look back at Hubble's best images
For 30 years, the Hubble Space Telescope has been providing us with breathtaking images from distant corners of the universe. Here's a look back at some of its finest pictures.
Image: NASA/Newscom/picture alliance
Computer glitch solved
NASA's Hubble Space Telescope wasn't able to send images between June 13 and July 15, 2021. A faulty computer memory system halted the telescope's operations. Only retired NASA experts managed to get it working again. For more than three decades, Hubble has provided fascinating images of distant stars and galaxies.
Image: ESA
Stars are born
This is one of the most photogenic examples of the many turbulent stellar nurseries the Hubble Space Telescope has observed during its lifetime. The portrait features the giant nebula NGC 2014 and its neighbor, NGC 2020, which together form part of a vast star-forming region in the Large Magellanic Cloud. This satellite galaxy of the Milky Way is approximately 163,000 light-years away.
Image: NASA/ESA/TScI
Better than 'Star Wars'
Just as a new episode of "Star Wars" hit cinemas in 2015, Hubble took this picture of a cosmic lightsaber. The celestial structure is located about 1,300 light-years away. It's the birth of a star system — two cosmic jets beaming outward from a newborn star and some interstellar dust. The space telescope takes breathtaking pictures. Here are some more …
Image: NASA/ESA/Hubble
Eyes in space
Since 1990, the king of all space telescopes has been orbiting Earth at a speed of over 17,000 miles per hour (27,000 kilometers per hour) and an altitude of 340 miles (550 kilometers). Hubble is 11 meters (36 feet) long and weighs 11 metric tons (12.2 US tons), making it comparable in weight and size to a school bus.
Image: NASA/Getty Images
Scoping out cosmic bubbles
Hubble has helped us understand the birth of stars and planets, approximate the age of the universe and examine the nature of dark matter. Here we see a gigantic ball of gas created by a supernova explosion.
Image: AP
Fleeting colors
Different gases emit all kinds of different colors. Red, for instance, is a sign of sulfur. Green is hydrogen. And blue is oxygen.
The first pictures Hubble sent back were a catastrophe, however, because its main mirror had been ground to the wrong shape. In 1993, Space Shuttle Endeavor took experts to Hubble to fix the problem, giving it a pair of glasses. That was just one of five updates the telescope has received over the years, the last one coming in 2009.
Image: picture-alliance/dpa/Nasa
Space kindergarten
Hubble took this amazing picture in December 2009. The blue dots are very young stars, just a few million years old. This kindergarten of stars is found in the Large Magellanic Cloud, a nearby galaxy, and a satellite of our Milky Way.
Image: picture-alliance/dpa/Nasa
Butterfly?
How about this snapshot from space? Nobody really knows what exactly Hubble had in its lens here, but that doesn't mean the shot is any less stunning. This image is just one of over 30,000 that Hubble has captured for the ages.
Image: NASA/ESA/ Hubble Heritage Team
Divine sombrero
This virtually transcendent photograph is — like most Hubble images — a composition of many single shots. The Sombrero Galaxy is an unbarred spiral galaxy in the Virgo constellation and is located a mere 28 million light-years from the Earth.
Image: NASA/ESA/ Hubble Heritage Team
Hubble in the flesh
The telescope was named after the American astronomer Edwin Powell Hubble (1889-1953). He was the first person to observe that the universe is expanding. With this finding, he paved the way for our current cosmological understanding of the Big Bang as initiator of the universe.
Image: picture-alliance/dpa
Pillars of Creation
These column-shaped structures are found in the Eagle Nebula, around 7,000 light-years away from Earth. They were documented by Hubble and have received worldwide recognition under the name "Pillars of Creation."
Image: NASA, ESA/Hubble and the Hubble Heritage Team
In the starting blocks
Hubble is going strong, again. Due to its constantly sinking orbit, however, the telescope may reenter the Earth's atmosphere in 2024 and burn up. But its successor is already set: James Webb, being tested inside a thermal vacuum chamber here, is scheduled to be launched this year. Its workplace will be about 1.5 million kilometers (932,000 miles) from Earth.
Image: picture-alliance/dpa/Nasa/Chris Gunn
Space smiley
This, by the way, is another one of Hubble's creations — a space smiley! The easy explanation? It was made by bending light.
