Wednesday, February 14, 2018

Across The Universe - Good News For The Search For Life, The Trappist System Might Be Rich In Water

Good News For The Search For Life, The Trappist System Might Be Rich In Water:

When we finally find life somewhere out there beyond Earth, it’ll be at the end of a long search. Life probably won’t announce its presence to us, we’ll have to follow a long chain of clues to find it. Like scientists keep telling us, at the start of that chain of clues is water.

The discovery of the TRAPPIST-1 system last year generated a lot of excitement. 7 planets orbiting the star TRAPPIST-1, only 40 light years from Earth. At the time, astronomers thought at least some of them were Earth-like. But now a new study shows that some of the planets could hold more water than Earth. About 250 times more.

This new study focuses on the density of the 7 TRAPPIST-1 planets. Trying to determine that density is a challenging task, and it involved some of the powerhouses in the world of telescopes. The Spitzer Space Telescope, the Kepler Space Telescope, and the SPECULOOS (Search for habitable Planets EClipsing ULtra-cOOl Stars) facility at ESO’s Paranal Observatory were all used in the study.

This artist’s impression shows several of the planets orbiting the ultra-cool red dwarf star TRAPPIST-1. New observations, when combined with very sophisticated analysis, have now yielded good estimates of the densities of all seven of the Earth-sized planets and suggest that they are rich in volatile materials, probably water. Image: ESO/M. Kornmesser

In this study, the observations from the three telescopes were subjected to complex computer modelling to determine the densities of the 7 TRAPPIST planets. As a result, we now know that they are all mostly made of rock, and that some of them could be 5% water by mass. (Earth is only about 0.02% water by mass.)

Finding the densities of these planets was not easy. To do so, scientists had to determine both the mass and the size. The TRAPPIST-1 planets were found using the transit method, where the light of the host star dips as the planets pass between their star and us. The transit method gives us a pretty good idea of the size of the planets, but that’s it.

It’s a lot harder to find the mass, because planets with different masses can have the same orbits and we can’t tell them apart. But in multi-planet systems like TRAPPIST-1, there is a way.

As the planets orbit the TRAPPIST-1 star, more massive planets disturb the orbits of the other planets more than lighter ones. This changes the timing of the transits. These effects are “complicated and very subtle” according to the team, and it took a lot of observation and measurement of the transit timing—and very complex computer modelling—to determine their densities.

Lead author Simon Grimm explains how it was done: “The TRAPPIST-1 planets are so close together that they interfere with each other gravitationally, so the times when they pass in front of the star shift slightly. These shifts depend on the planets’ masses, their distances and other orbital parameters. With a computer model, we simulate the planets’ orbits until the calculated transits agree with the observed values, and hence derive the planetary masses.”

So, what about the water?

First of all, this study didn’t detect water. It detected volatile material which is probably water.

Whether or not they’ve confirmed the presence of water, these are still very important results. We’re getting good at finding exoplanets, and the next step is to determine the properties of any atmospheres that exoplanets have.

Team member Eric Agol comments on the significance: “A goal of exoplanet studies for some time has been to probe the composition of planets that are Earth-like in size and temperature. The discovery of TRAPPIST-1 and the capabilities of ESO’s facilities in Chile and the NASA Spitzer Space Telescope in orbit have made this possible — giving us our first glimpse of what Earth-sized exoplanets are made of!”

This diagram compares the sizes, masses and estimated temperatures of the TRAPPIST-1 planets with Solar System planets. The colours indicate temperatures and the black line matches the densities and composition of the terrestrial planets in the Solar System. Planets above the line are less dense and planets below are more dense. Image: EXO/S.Grimm et. al.

This study doesn’t tell us if any of the TRAPPIST planets have life on them, or even if they’re habitable. It’s just one more step on the path to hopefully, maybe, one day, finding life somewhere. Study co-author Brice-Olivier Demory, at the University of Bern, said as much: “Densities, while important clues to the planets’ compositions, do not say anything about habitability. However, our study is an important step forward as we continue to explore whether these planets could support life.”

This diagram compares the masses and energy input of the seven TRAPPIST-1 planets, along with the properties of the four innermost Solar System planets. Image: NASA/JPL-Caltech

This is what the study determined about the different planets in the TRAPPIST system:

TRAPPIST 1-b and 1c are the two innermost planets and are likely to have rocky cores and be surrounded by atmospheres much thicker than Earth’s.
TRAPPIST-1d is the lightest of the planets at about 30 percent the mass of Earth. We’re uncertain whether it has a large atmosphere, an ocean or an ice layer.
TRAPPIST-1e is a bit of a surprise. It’s the only planet in the system slightly denser than Earth. It may have a denser iron core, and it does not necessarily have a thick atmosphere, ocean or ice layer. TRAPPIST-1e is a mystery because it appears to be so much rockier than the rest of the planets. It’s the most similar to Earth, in size, density and the amount of radiation it receives from its star.
TRAPPIST-1f, g and h might have frozen surfaces. If they have thin atmospheres, they would be unlikely to contain the heavy molecules that we find on Earth, such as carbon dioxide.

The TRAPPIST-1 system is going to be studied for a very long time. It promises to be one of the first targets for the James Webb Space Telescope (we hope.) It’s a very intriguing system, and whether or not any of the planets are deemed habitable, studying them will teach us a lot about our search for water, habitability, and life.

The post Good News For The Search For Life, The Trappist System Might Be Rich In Water appeared first on Universe Today.

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The National Aeronautics and Space Administration (NASA) is the United States government agency responsible for the civilian space program as well as aeronautics and aerospace research. President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA's predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

UFO SIGHTINGS PHOTO PHOTOGRAPHY

The Oxford English Dictionary defines a UFO as "An unidentified flying object; a 'flying saucer'." The first published book to use the word was authored by Donald E. Keyhoe. The acronym "UFO" was coined by Captain Edward J. Ruppelt, who headed Project Blue Book, then the USAF's official investigation of UFOs. He wrote, "Obviously the term 'flying saucer' is misleading when applied to objects of every conceivable shape and performance. For this reason the military prefers the more general, if less colorful, name: unidentified flying objects. UFO (pronounced Yoo-foe) for short." Other phrases that were used officially and that predate the UFO acronym include "flying flapjack", "flying disc", "unexplained flying discs", "unidentifiable object", and "flying saucer". The phrase "flying saucer" had gained widespread attention after the summer of 1947. On June 24, a civilian pilot named Kenneth Arnold reported seeing nine objects flying in formation near Mount Rainier. Arnold timed the sighting and estimated the speed of discs to be over 1,200 mph (1,931 km/h). At the time, he described the objects' shape as being somewhat disc-like or saucer-like, leading to newspaper accounts of "flying saucers" and "flying discs". In popular usage the term UFO came to be used to refer to claims of alien spacecraft. and because of the public and media ridicule associated with the topic, some investigators prefer to use such terms as unidentified aerial phenomenon (or UAP) or anomalous phenomena, as in the title of the National Aviation Reporting Center on Anomalous Phenomena (NARCAP).

UFO PHOTO PHOTOGRAPHY

UFO - Unidentified Flying Object An unidentified flying object, or UFO, in its most general definition, is any apparent anomaly in the sky that is not identifiable as a known object or phenomenon. Culturally, UFOs are associated with claims of visitation by extraterrestrial life or government-related conspiracy theories, and have become popular subjects in fiction. While UFOs are often later identified, sometimes identification may not be possible owing to the usually low quality of evidence related to UFO sightings (generally anecdotal evidence and eyewitness accounts). Stories of fantastical celestial apparitions have been told since antiquity, but the term "UFO" (or "UFOB") was officially created in 1953 by the United States Air Force (USAF) to serve as a catch-all for all such reports. In its initial definition, the USAF stated that a "UFOB" was "any airborne object which by performance, aerodynamic characteristics, or unusual features, does not conform to any presently known aircraft or missile type, or which cannot be positively identified as a familiar object." Accordingly, the term was initially restricted to that fraction of cases which remained unidentified after investigation, as the USAF was interested in potential national security reasons and/or "technical aspects" (see Air Force Regulation 200-2). During the late 1940s and through the 1950s, UFOs were often referred to popularly as "flying saucers" or "flying discs". The term UFO became more widespread during the 1950s, at first in technical literature, but later in popular use. UFOs garnered considerable interest during the Cold War, an era associated with a heightened concern for national security. Various studies have concluded that the phenomenon does not represent a threat to national security nor does it contain anything worthy of scientific pursuit (e.g., 1951 Flying Saucer Working Party, 1953 CIA Robertson Panel, USAF Project Blue Book, Condon Committee).

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