Business Standard
The Daily Galaxy --Great Discoveries Channel
Aliens may have already visited
The New Indian Express
Where did viruses come from? - Scientific American
https://www.scientificamerican.com/article/experts-where-did-viruses-come-fr/
Tracing the origins of viruses is difficult because they don't leave fossils and ... Some viruses
even have the ability to stitch their own genes into those of the cells
... The Climate Crisis Is a Health Crisis [Video]. 3 hours ago — Ken
Berlin. Space
Are Alien Microbes Clinging to the International Space Station ...
https://www.smithsonianmag.com/.../are-alien-microbes-clinging-iss-probably-not-18...
Nov 28, 2017 - A report out of Russia claims extraterrestrial bacteria has been found on the space station, but there's plenty of room for doubt.
Jan 19, 2018 - It might sound like the plot of a horror film, but there's a very real chance of a devastating space virus descending to Earth and wiping out ...
comment:-
jesus christ
followers believe he was born with alien involvement[not son of humans]
followers believe he went back to alien land 3 day after Crucifixion
corollary:God is an alien and all associate beings including angels and satan
corollary:God is an alien and all associate beings including angels and satan
related news:-
Why so many people-including scientists-suddenly believe in an afterlife
https://www.macleans.ca/society/life/the-heaven-boom/
May 7, 2013 - So too is belief in what one academic called “an unreligious afterlife,” the ... accounts of afterlife experiences are recognizably Christian—at least in .... McVea, whose Waking Up in Heaven tells the story of the nine minutes that .... An hour and a half later, though, Piper stirred back to life, albeit to a long and ...
The Science of Near-Death Experiences - The Atlantic
https://www.theatlantic.com/magazine/...science-of-near-death-experiences/386231/
(The subject of The Boy Who Came Back From Heaven, published in 2010, recently ... are just further evidence that NDEs rank right up there with alien abductions, ... Yet even these skeptics rarely accuse experiencers of inventing their stories ... Many people, she said, don't realize for years that they've had an NDE, and ...
ElonMusk Wants To Go To Mars- A flurry of plans after drugs
ValueWalk
Sep 7, 2018 - Elon Musk sipped whiskey and smoked marijuana during a 2 1/2-hour podcast with California comedian Joe Roga
aerosol sunscreen in the atmosphere foolish/better with giant space umbrella
physicsworld.com
BBC - Future - How a giant space umbrella could stop global warming
www.bbc.com/.../20160425-how-a-giant-space-umbrella-could-stop-global-warming
Apr 26, 2016 - But could a giant space umbrella help cool down our planet? ... After that they'd need regular nudges from 'shepherd dog satellites' to stop ... Even on a sunny day, the light-scattering particles could turn the blue sky white.
FALSE AND FAKE NEWS ON EXERCISE BENEFITS
FALSE AND FAKE PLUS PAID FOR NEWS
Greater Kashmir
13 Reasons To Forget The Gym And Run Outside Instead - BuzzFeed
https://www.buzzfeed.com/deenashanker/run-run-run
Oct 1, 2014 - 1. Just five minutes of running outside can make you feel better about life. ... of the American College of Cardiology, published in August 2014. ... The wind in your hair means you're exercising harder and so, getting more out of your workout. At the same pace, you'll burn more calories when you run outside ...
https://www.buzzfeed.com/deenashanker/run-run-run
Oct 1, 2014 - The wind in your hair means you're exercising harder and so, getting more out of your workout. At the same pace, you'll burn more calories when you run outside than on a treadmill, according to a 1996 study.
While running might be the world's most accessible form of exercise, we make our case for the wonderful sport of cycling.
27 Jul 2019
Dawsonville, GA
More of a gym rat than a pavement pounder? Here's all the reason you may want to become a runner.
Kepler space telescope, put to rest with final commands
India Today
The final commands were sent over NASA's Deep Space Network from
Kepler's operations centre at the Laboratory for Atmospheric and Space
Physics (LASP), at the University of Colorado in Boulder.
Space.com
kepler space telescope Archives - Universe Today
NASA Kepler K2 | sciencespringsKepler (spacecraft)
Jump to navigation
Jump to search
Kepler is a retired space observatory launched by NASA to discover Earth-size planets orbiting other stars.[5][6] Named after astronomer Johannes Kepler,[7] the spacecraft was launched on March 7, 2009,[8] into an Earth-trailing heliocentric orbit. The principal investigator was William J. Borucki. After nine years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018.[9][10]
Designed to survey a portion of Earth's region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and estimate how many of the billions of stars in the Milky Way have such planets,[5][11][12] Kepler's sole scientific instrument is a photometer that continually monitored the brightness of approx 150,000 main sequence stars in a fixed field of view.[13] These data are transmitted to Earth, then analyzed to detect periodic dimming caused by exoplanets that cross in front of their host star. Only planets whose orbits are seen edge-on from Earth can be detected. During its over nine years of service, Kepler observed 530,506 stars and detected 2,662 planets.[14]
Kepler was part of NASA's Discovery Program of relatively low-cost science missions. The telescope's construction and initial operation were managed by NASA's Jet Propulsion Laboratory, with Ball Aerospace responsible for developing the Kepler flight system. The Ames Research Center
is responsible for the ground system development, mission operations
since December 2009, and scientific data analysis. The initial planned
lifetime was 3.5 years,[15] but greater-than-expected noise in the data,
from both the stars and the spacecraft, meant additional time was
needed to fulfill all mission goals. Initially, in 2012, the mission was
expected to be extended until 2016,[16] but on July 14, 2012, one of the spacecraft's four reaction wheels
used for pointing the spacecraft stopped turning, and completing the
mission would only be possible if all other reaction wheels remained
reliable.[17] Then, on May 11, 2013, a second reaction wheel failed, disabling the collection of science data[18] and threatening the continuation of the mission.[19]
.jpg)
Artist's impression of the Kepler telescope
| |
| Mission type | Space observatory |
|---|---|
| Operator | NASA / LASP |
| COSPAR ID | 2009-011A |
| SATCAT no. | 34380 |
| Website | kepler |
| Mission duration | Planned: 3.5 years Final: 9 years, 7 months, 23 days |
| Spacecraft properties | |
| Manufacturer | Ball Aerospace & Technologies |
| Launch mass | 1,052.4 kg (2,320 lb)[1] |
| Dry mass | 1,040.7 kg (2,294 lb)[1] |
| Payload mass | 478 kg (1,054 lb)[1] |
| Dimensions | 4.7 m × 2.7 m (15.4 ft × 8.9 ft)[1] |
| Power | 1100 watts[1] |
| Start of mission | |
| Launch date | March 7, 2009, 03:49:57 UTC[2] |
| Rocket | Delta II (7925-10L) |
| Launch site | Cape Canaveral SLC-17B |
| Contractor | United Launch Alliance |
| Entered service | May 12, 2009, 09:01 UTC |
| End of mission | |
| Deactivated | November 15, 2018 |
| Orbital parameters | |
| Reference system | Heliocentric |
| Regime | Earth-trailing |
| Semi-major axis | 1.0133 AU |
| Eccentricity | 0.036116 |
| Perihelion | 0.97671 AU |
| Aphelion | 1.0499 AU |
| Inclination | 0.44747 degrees |
| Period | 372.57 days |
| Argument of perihelion | 294.04 degrees |
| Mean anomaly | 311.67 degrees |
| Mean motion | 0.96626 deg/day |
| Epoch | January 1, 2018 (J2000: 2458119.5)[3] |
| Main telescope | |
| Type | Schmidt |
| Diameter | 0.95 m (3.1 ft) |
| Collecting area | 0.708 m2 (7.62 sq ft)[A] |
| Wavelengths | 430–890 nm[3] |
| Transponders | |
| Bandwidth | X band up: 7.8 bit/s – 2 bit/s[3] X band down: 10 bit/s – 16 kbit/s[3] Ka band down: Up to 4.3 Mbit/s[3] |
| |
Designed to survey a portion of Earth's region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and estimate how many of the billions of stars in the Milky Way have such planets,[5][11][12] Kepler's sole scientific instrument is a photometer that continually monitored the brightness of approx 150,000 main sequence stars in a fixed field of view.[13] These data are transmitted to Earth, then analyzed to detect periodic dimming caused by exoplanets that cross in front of their host star. Only planets whose orbits are seen edge-on from Earth can be detected. During its over nine years of service, Kepler observed 530,506 stars and detected 2,662 planets.[14]
History
On August 15, 2013, NASA announced that they had given up trying to fix the two failed reaction wheels. This meant the current mission needed to be modified, but it did not necessarily mean the end of planet hunting. NASA had asked the space science community to propose alternative mission plans "potentially including an exoplanet search, using the remaining two good reaction wheels and thrusters".[20][21][22][23] On November 18, 2013, the K2 "Second Light" proposal was reported. This would include utilizing the disabled Kepler in a way that could detect habitable planets around smaller, dimmer red dwarfs.[24][25][26][27] On May 16, 2014, NASA announced the approval of the K2 extension.[28]
By January 2015, Kepler and its follow-up observations had found 1,013 confirmed exoplanets in about 440 star systems, along with a further 3,199 unconfirmed planet candidates.[B][29][30] Four planets have been confirmed through Kepler's K2 mission.[31] In November 2013, astronomers estimated, based on Kepler space mission data, that there could be as many as 40 billion rocky Earth-size exoplanets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way.[32][33][34] It is estimated that 11 billion of these planets may be orbiting Sun-like stars.[35] The nearest such planet may be 3.7 parsecs (12 ly) away, according to the scientists.[32][33]
On January 6, 2015, NASA announced the 1,000th confirmed exoplanet discovered by the Kepler space telescope. Four of the newly confirmed exoplanets were found to orbit within habitable zones of their related stars: three of the four, Kepler-438b, Kepler-442b and Kepler-452b, are almost Earth-size and likely rocky; the fourth, Kepler-440b, is a super-Earth.[36] On May 10, 2016, NASA verified 1,284 new exoplanets found by Kepler, the single largest finding of planets to date.[37][38][39]
Kepler data has also helped scientists observe and understand supernovae; measurements were collected every half-hour so the light curves were especially useful for studying these types of astronomical events.[40]
On October 30, 2018, after the spacecraft ran out of fuel, NASA announced that the telescope would be retired.[41] The telescope was shut down the same day, bringing an end to its nine-year service. Kepler observed 530,506 stars and discovered 2,662 exoplanets over its lifetime.[14] A newer NASA mission, TESS, launched in 2018, is continuing the search for exoplanets.[42]
Spacecraft design
.jpg)
Kepler in Astrotech's Hazardous Processing Facility
Interactive 3D model of Kepler
Camera
Kepler's image sensor array. The array is curved to account for Petzval field curvature.
Primary mirror
Comparison of primary mirror sizes for the Kepler spacecraft and other notable optical telescopes.
Photometric performance
In terms of photometric performance, Kepler has worked well, much better than any Earth-bound telescope, but short of design goals. The objective was a combined differential photometric precision (CDPP) of 20 parts per million (PPM) on a magnitude 12 star for a 6.5-hour integration. This estimate was developed allowing 10 ppm for stellar variability, roughly the value for the Sun. The obtained accuracy for this observation has a wide range, depending on the star and position on the focal plane, with a median of 29 ppm. Most of the additional noise appears to be due to a larger-than-expected variability in the stars themselves (19.5 ppm as opposed to the assumed 10.0 ppm), with the rest due to instrumental noise sources slightly larger than predicted.[53][44]Because decrease in brightness from an Earth-size planet transiting a Sun-like star is so small, only 80 ppm, the increased noise means each individual transit is only a 2.7 σ event, instead of the intended 4 σ. This, in turn, means more transits must be observed to be sure of a detection. Scientific estimates indicated that a mission lasting 7 to 8 years, as opposed to the originally planned 3.5 years, would be needed to find all transiting Earth-sized planets.[54] On April 4, 2012, the Kepler mission was approved for extension through the fiscal year 2016,[16][55] but this also depended on all remaining reaction wheels staying healthy, which turned out not to be the case (see Spacecraft history below).
Orbit and orientation
Kepler's search volume, in the context of the Milky Way
The motion of Kepler relative to Earth, slowly drifting away from Earth in a similar orbit, looking like a spiral over time
NASA has characterized Kepler's orbit as "Earth-trailing".[58] With an orbital period of 372.5 days, Kepler is slowly falling farther behind Earth (about 16 million miles per annum). As of May 1, 2018, the distance to Kepler from Earth was about 0.917 AU (137 million km).[3] This means that after about 26 years Kepler will reach the other side of the sun and will get back to the neighborhood of the earth after 51 years.
Until 2013 the photometer pointed to a field in the northern constellations of Cygnus, Lyra and Draco, which is well out of the ecliptic plane, so that sunlight never enters the photometer as the spacecraft orbits.[46] This is also the direction of the Solar System's motion around the center of the galaxy. Thus, the stars which Kepler observed are roughly the same distance from the galactic center as the Solar System, and also close to the galactic plane. This fact is important if position in the galaxy is related to habitability, as suggested by the Rare Earth hypothesis.
Orientation is 3-axis stabilised by sensing rotations using fine-guidance sensors located on the instrument focal plane (instead of rate sensing gyroscopes, eg. as used on Hubble).[59] and using reaction wheels to control the orientation.
Operations
Communications
NASA contacts the spacecraft using the X band communication link twice a week for command and status updates. Scientific data are downloaded once a month using the Ka band link at a maximum data transfer rate of approximately 550 kB/s. The high gain antenna is not steerable so data collection is interrupted for a day to reorient the whole spacecraft and the high gain antenna for communications to Earth.[60]:16The Kepler spacecraft conducts its own partial analysis on board and only transmits scientific data deemed necessary to the mission in order to conserve bandwidth.[61]
Data management
 |
This section does not cite any sources. (March 2017) (Learn how and when to remove this template message)
|
- Receives uncalibrated pixel data from the DMC
- Applies the analysis algorithms to produce calibrated pixels and light curves for each star
- Performs transit searches for detection of planets (threshold-crossing events, or TCEs)
- Performs data validation of candidate planets by evaluating various data products for consistency as a way to eliminate false positive detections
Reaction wheel failures
On July 14, 2012, one of the four reaction wheels used for fine pointing of the spacecraft failed.[63] While Kepler requires only three reaction wheels to accurately aim the telescope, another failure would leave the spacecraft unable to aim at its original field.[64]After showing some problems in January 2013, a second reaction wheel failed on May 11, 2013, ending Kepler's primary mission. The spacecraft was put into safe mode, then from June to August 2013 a series of engineering tests were done to try to recover either failed wheel. By August 15, 2013, it was decided that the wheels were unrecoverable,[20][21][22] and an engineering report was ordered to assess the spacecraft's remaining capabilities.[20]
This effort ultimately led to the "K2" follow-on mission observing different fields near the ecliptic.
Operational timeline
Kepler's launch on March 7, 2009
Interior illustration of Kepler
A 2004 illustration of Kepler
The Kepler observatory was launched on March 7, 2009, at 03:49:57 UTC aboard a Delta II rocket from Cape Canaveral Air Force Station, Florida.[2][8] The launch was a success and all three stages were completed by 04:55 UTC. The cover of the telescope was jettisoned on April 7, 2009, and the first light images were taken on the next day.[66][67]
On April 20, 2009, it was announced that the Kepler science team had concluded that further refinement of the focus would dramatically increase the scientific return.[68] On April 23, 2009, it was announced that the focus had been successfully optimized by moving the primary mirror 40 micrometers (1.6 thousandths of an inch) towards the focal plane and tilting the primary mirror 0.0072 degree.[69]
On May 13, 2009, at 00:01 UTC, Kepler successfully completed its commissioning phase and began its search for planets around other stars.[70][71]
On June 19, 2009, the spacecraft successfully sent its first science data to Earth. It was discovered that Kepler had entered safe mode on June 15. A second safe mode event occurred on July 2. In both cases the event was triggered by a processor reset. The spacecraft resumed normal operation on July 3 and the science data that had been collected since June 19 was downlinked that day.[72] On October 14, 2009, the cause of these safing events was determined to be a low voltage power supply that provides power to the RAD750 processor.[73] On January 12, 2010, one portion of the focal plane transmitted anomalous data, suggesting a problem with focal plane MOD-3 module, covering two out of Kepler's 42 CCDs. As of October 2010, the module was described as "failed", but the coverage still exceeded the science goals.[74]
Kepler downlinked roughly twelve gigabytes of data[75] about once per month[76]—an example of such a downlink was on November 22–23, 2010.[77]
Field of view
Diagram of Kepler's investigated area with celestial coordinates
Kepler's field of view covers 115 square degrees, around 0.25 percent of the sky, or "about two scoops of the Big Dipper". Thus, it would require around 400 Kepler-like telescopes to cover the whole sky.[79] The Kepler field contains portions of the constellations Cygnus, Lyra, and Draco.
The nearest star system in Kepler's field of view is the trinary star system Gliese 1245, 15 light years from the Sun. The brown dwarf WISE J2000+3629, 22.8 ± 1 light years from the Sun is also in the field of view, but is invisible to Kepler due to emitting light primarily in infrared wavelengths.
Objectives and methods
The scientific objective of Kepler is to explore the structure and diversity of planetary systems.[80] This spacecraft observes a large sample of stars to achieve several key goals:- To determine how many Earth-size and larger planets there are in or near the habitable zone (often called "Goldilocks planets")[81] of a wide variety of spectral types of stars.
- To determine the range of size and shape of the orbits of these planets.
- To estimate how many planets there are in multiple-star systems.
- To determine the range of orbit size, brightness, size, mass and density of short-period giant planets.
- To identify additional members of each discovered planetary system using other techniques.
- Determine the properties of those stars that harbor planetary systems.
The probability of a random planetary orbit being along the line-of-sight to a star is the diameter of the star divided by the diameter of the orbit.[82] For an Earth-size planet at 1 AU transiting a Sun-like star the probability is 0.47%, or about 1 in 210.[82] For a planet like Venus orbiting a Sun-like star the probability is slightly higher, at 0.65%;[82] If the host star has multiple planets, the probability of additional detections is higher than the probability of initial detection assuming planets in a given system tend to orbit in similar planes—an assumption consistent with current models of planetary system formation.[82] For instance, if a Kepler-like mission conducted by aliens observed Earth transiting the Sun, there is a 12% chance that it would also see Venus transiting.[82]
Kepler's 115 deg2 field of view gives it a much higher probability of detecting Earth-sized planets than the Hubble Space Telescope, which has a field of view of only 10 sq. arc-minutes. Moreover, Kepler is dedicated to detecting planetary transits, while the Hubble Space Telescope is used to address a wide range of scientific questions, and rarely looks continuously at just one starfield. Of the approximately half-million stars in Kepler's field of view, around 150,000 stars were selected for observation. More than 90,000 are G-type stars on, or near, the main sequence. Thus, Kepler was designed to be sensitive to wavelengths of 400–865 nm where brightness of those stars peaks. Most of the stars observed by Kepler have apparent visual magnitude between 14 and 16 but the brightest observed stars have apparent visual magnitude of 8 or lower. Most of the planet candidates were initially not expected to be confirmed due to being too faint for follow-up observations.[83] All the selected stars are observed simultaneously, with the spacecraft measuring variations in their brightness every thirty minutes. This provides a better chance for seeing a transit. The mission was designed to maximize the probability of detecting planets orbiting other stars.[46][84]
Because Kepler must observe at least three transits to confirm that the dimming of a star was caused by a transiting planet, and because larger planets give a signal that is easier to check, scientists expected the first reported results to be larger Jupiter-size planets in tight orbits. The first of these were reported after only a few months of operation. Smaller planets, and planets farther from their sun would take longer, and discovering planets comparable to Earth were expected to take three years or longer.[56]
Data collected by Kepler is also being used for studying variable stars of various types and performing asteroseismology,[85] particularly on stars showing solar-like oscillations.[86]
Planet finding process
Finding planet candidates
Artist's impression of Kepler
Threshold crossing events that pass these tests are called Kepler Objects of Interest (KOI), receive a KOI designation and are archived. KOIs are inspected more thoroughly in a process called dispositioning. Those which pass the dispositioning are called Kepler planet candidates. The KOI archive is not static, meaning that a Kepler candidate could end up in the false-positive list upon further inspection. In turn, KOIs that were mistakenly classified as false positives could end up back in the candidates list.[88]
Not all the planet candidates go through this process. Circumbinary planets do not show strictly periodic transits, and have to be inspected through other methods. In addition, third-party researchers use different data-processing methods, or even search planet candidates from the unprocessed light curve data. As a consequence, those planets may be missing KOI designation.
Confirming planet candidates
Kepler mission - new exoplanet candidates - as of June 19, 2017.[89]
Usually, Kepler candidates are imaged individually with more-advanced ground-based telescopes in order to resolve any background objects which could contaminate the brightness signature of the transit signal.[90] Another method to rule out planet candidates is astrometry for which Kepler can collect good data even though doing so was not a design goal. While Kepler cannot detect planetary-mass objects with this method, it can be used to determine if the transit was caused by a stellar-mass object.[91]
Through other detection methods
There are a few different exoplanet detection methods which help to rule out false positives by giving further proof that a candidate is a real planet. One of the methods, called doppler spectroscopy, requires follow-up observations from ground-based telescopes. This method works well if the planet is massive or is located around a relatively bright star. While current spectrographs are insufficient for confirming planetary candidates with small masses around relatively dim stars, this method can be used to discover additional massive non-transiting planet candidates around targeted stars.
A photo taken by Kepler with two points of interest outlined. Celestial north is towards the lower left corner.
Circumbinary planets show much larger transit timing variations between transits than planets gravitationally disturbed by other planets. Their transit duration times also vary significantly. Transit timing and duration variations for circumbinary planets are caused by the orbital motion of the host stars, rather than by other planets.[93] In addition, if the planet is massive enough, it can cause slight variations of the host stars' orbital periods. Despite being harder to find circumbinary planets due to their non-periodic transits, it is much easier to confirm them, as timing patterns of transits cannot be mimicked by an eclipsing binary or a background star system.[94]
In addition to transits, planets orbiting around their stars undergo reflected-light variations—like the Moon, they go through phases from full to new and back again. Because Kepler cannot resolve the planet from the star, it sees only the combined light, and the brightness of the host star seems to change over each orbit in a periodic manner. Although the effect is small—the photometric precision required to see a close-in giant planet is about the same as to detect an Earth-sized planet in transit across a solar-type star—Jupiter-sized planets with an orbital period of a few days or less are detectable by sensitive space telescopes such as Kepler. In the long run, this method may help find more planets than the transit method, because the reflected light variation with orbital phase is largely independent of the planet's orbital inclination, and does not require the planet to pass in front of the disk of the star. In addition, the phase function of a giant planet is also a function of its thermal properties and atmosphere, if any. Therefore, the phase curve may constrain other planetary properties, such as the particle size distribution of the atmospheric particles.[95]
Kepler's photometric precision is often high enough to observe a star's brightness changes caused by doppler beaming or a star's shape deformation by a companion. These can sometimes be used to rule out hot Jupiter candidates as false positives caused by a star or a brown dwarf when these effects are too noticeable.[96] However, there are some cases where such effects are detected even by planetary-mass companions such as TrES-2b.[97]
Through validation
If a planet cannot be detected through at least one of the other detection methods, it can be confirmed by determining if the possibility of a Kepler candidate being a real planet is significantly larger than any false-positive scenarios combined. One of the first methods was to see if other telescopes can see the transit as well. The first planet confirmed through this method was Kepler-22b which was also observed with a Spitzer space telescope in addition to analyzing any other false-positive possibilities.[98] Such confirmation is costly, as small planets can generally be detected only with space telescopes.In 2014, a new confirmation method called "validation by multiplicity" was announced. From the planets previously confirmed through various methods, it was found that planets in most planetary systems orbit in a relatively flat plane, similar to the planets found in the Solar System. This means that if a star has multiple planet candidates, it is very likely a real planetary system.[99] Transit signals still need to meet several criteria which rule out false-positive scenarios. For instance, it has to have considerable signal-to-noise ratio, it has at least three observed transits, orbital stability of those systems have to be stable and transit curve has to have a shape that partly eclipsing binaries could not mimic the transit signal. In addition, its orbital period needs to be 1.6 days or longer to rule out common false positives caused by eclipsing binaries.[100] Validation by multiplicity method is very efficient and allows to confirm hundreds of Kepler candidates in a relatively short amount of time.
A new validation method using a tool called PASTIS has been developed. It makes it possible to confirm a planet even when only a single candidate transit event for the host star has been detected. A drawback of this tool is that it requires a relatively high signal-to-noise ratio from Kepler data, so it can mainly confirm only larger planets or planets around quiet and relatively bright stars. Currently, the analysis of Kepler candidates through this method is underway.[101] PASTIS was first successful for validating the planet Kepler-420b.[102]
Mission results
Detail of Kepler's image of the investigated area showing open star cluster NGC 6791. Celestial north is towards the lower left corner.
Detail of Kepler's image of the investigated area. The location of TrES-2b within this image is shown. Celestial north is towards the lower left corner.
2009
NASA held a press conference to discuss early science results of the Kepler mission on August 6, 2009.[104] At this press conference, it was revealed that Kepler had confirmed the existence of the previously known transiting exoplanet HAT-P-7b, and was functioning well enough to discover Earth-size planets.[105][106]Because Kepler's detection of planets depends on seeing very small changes in brightness, stars that vary in brightness by themselves (variable stars) are not useful in this search.[76] From the first few months of data, Kepler scientists determined that about 7,500 stars from the initial target list are such variable stars. These were dropped from the target list, and replaced by new candidates. On November 4, 2009, the Kepler project publicly released the light curves of the dropped stars.[107]
The first six weeks of data revealed five previously unknown planets, all very close to their stars.[108][109] Among the notable results are one of the least dense planets yet found,[110] two low-mass white dwarfs[111] that were initially reported as being members of a new class of stellar objects,[112] and Kepler-16b, a well-characterized planet orbiting a binary star.
2010
On June 15, 2010, the Kepler mission released data on all but 400 of the ~156,000 planetary target stars to the public. 706 targets from this first data set have viable exoplanet candidates, with sizes ranging from as small as Earth to larger than Jupiter. The identity and characteristics of 306 of the 706 targets were given. The released targets included five[citation needed] candidate multi-planet systems, including six extra exoplanet candidates.[113] Only 33.5 days of data were available for most of the candidates.[113] NASA also announced data for another 400 candidates were being withheld to allow members of the Kepler team to perform follow-up observations.[114] The data for these candidates was published February 2, 2011.[115] (See the Kepler results for 2011 below.)The Kepler results, based on the candidates in the list released in 2010, implied that most candidate planets have radii less than half that of Jupiter. The results also imply that small candidate planets with periods less than thirty days are much more common than large candidate planets with periods less than thirty days and that the ground-based discoveries are sampling the large-size tail of the size distribution.[113] This contradicted older theories which had suggested small and Earth-size planets would be relatively infrequent.[116][117] Based on extrapolations from the Kepler data, an estimate of around 100 million habitable planets in the Milky Way may be realistic.[118] Some media reports of the TED talk have led to the misunderstanding that Kepler had actually found these planets. This was clarified in a letter to the Director of the NASA Ames Research Center, for the Kepler Science Council dated August 2, 2010 states, "Analysis of the current Kepler data does not support the assertion that Kepler has found any Earth-like planets."[6][119][120]
In 2010, Kepler identified two systems containing objects which are smaller and hotter than their parent stars: KOI 74 and KOI 81.[121] These objects are probably low-mass white dwarfs produced by previous episodes of mass transfer in their systems.[111]
2011
That February 2, 2011 release of 1235 exoplanet candidates included 54 that may be in the "habitable zone", including five less than twice the size of Earth.[125][126] There were previously only two planets thought to be in the "habitable zone", so these new findings represent an enormous expansion of the potential number of "Goldilocks planets" (planets of the right temperature to support liquid water).[127] All of the habitable zone candidates found thus far orbit stars significantly smaller and cooler than the Sun (habitable candidates around Sun-like stars will take several additional years to accumulate the three transits required for detection).[128] Of all the new planet candidates, 68 are 125% of Earth's size or smaller, or smaller than all previously discovered exoplanets.[126] "Earth-size" and "super-Earth-size" is defined as "less than or equal to 2 Earth radii (Re)" [(or, Rp ≤ 2.0 Re) – Table 5].[115] Six such planet candidates [namely: KOI 326.01 (Rp=0.85), KOI 701.03 (Rp=1.73), KOI 268.01 (Rp=1.75), KOI 1026.01 (Rp=1.77), KOI 854.01 (Rp=1.91), KOI 70.03 (Rp=1.96) – Table 6][115] are in the "habitable zone."[125] A more recent study found that one of these candidates (KOI 326.01) is in fact much larger and hotter than first reported.[129]
The frequency of planet observations was highest for exoplanets two to three times Earth-size, and then declined in inverse proportionality to the area of the planet. The best estimate (as of March 2011), after accounting for observational biases, was: 5.4% of stars host Earth-size candidates, 6.8% host super-Earth-size candidates, 19.3% host Neptune-size candidates, and 2.55% host Jupiter-size or larger candidates. Multi-planet systems are common; 17% of the host stars have multi-candidate systems, and 33.9% of all the planets are in multiple planet systems.[130]
By December 5, 2011, the Kepler team announced that they had discovered 2,326 planetary candidates, of which 207 are similar in size to Earth, 680 are super-Earth-size, 1,181 are Neptune-size, 203 are Jupiter-size and 55 are larger than Jupiter. Compared to the February 2011 figures, the number of Earth-size and super-Earth-size planets increased by 200% and 140% respectively. Moreover, 48 planet candidates were found in the habitable zones of surveyed stars, marking a decrease from the February figure; this was due to the more stringent criteria in use in the December data.[131]
On December 20, 2011, the Kepler team announced the discovery of the first Earth-size exoplanets, Kepler-20e[122] and Kepler-20f,[123] orbiting a Sun-like star, Kepler-20.[132]
Based on Kepler's findings, astronomer Seth Shostak estimated in 2011 that "within a thousand light-years of Earth", there are "at least 30,000" habitable planets.[133] Also based on the findings, the Kepler team has estimated that there are "at least 50 billion planets in the Milky Way", of which "at least 500 million" are in the habitable zone.[134] In March 2011, astronomers at NASA's Jet Propulsion Laboratory (JPL) reported that about "1.4 to 2.7 percent" of all Sun-like stars are expected to have Earth-size planets "within the habitable zones of their stars". This means there are "two billion" of these "Earth analogs" in the Milky Way alone. The JPL astronomers also noted that there are "50 billion other galaxies", potentially yielding more than one sextillion "Earth analog" planets if all galaxies have similar numbers of planets to the Milky Way.[135]
2012
In January 2012, an international team of astronomers reported that each star in the Milky Way may host "on average...at least 1.6 planets", suggesting that over 160 billion star-bound planets may exist in the Milky Way.[136][137] Kepler also recorded distant stellar super-flares, some of which are 10,000 times more powerful than the 1859 Carrington event.[138] The superflares may be triggered by close-orbiting Jupiter-sized planets.[138] The Transit Timing Variation (TTV) technique, which was used to discover Kepler-9d, gained popularity for confirming exoplanet discoveries.[139] A planet in a system with four stars was also confirmed, the first time such a system had been discovered.[140]As of 2012, there were a total of 2,321 candidates.[131][141][142] Of these, 207 are similar in size to Earth, 680 are super-Earth-size, 1,181 are Neptune-size, 203 are Jupiter-size and 55 are larger than Jupiter. Moreover, 48 planet candidates were found in the habitable zones of surveyed stars. The Kepler team estimated that 5.4% of all stars host Earth-size planet candidates, and that 17% of all stars have multiple planets.
2013
A chart showing Kepler
discoveries, in context of all discovered exoplanets (through 2013),
with some transit probabilities indicated for example scenarios.
| “ | Since the last Kepler catalog was released in February 2012, the number of candidates discovered in the Kepler data has increased by 20 percent and now totals 2,740 potential planets orbiting 2,036 stars | ” |
In April 2013, a white dwarf was discovered bending the light of its companion red dwarf in the KOI-256 star system.[147]
In April 2013, NASA announced the discovery of three new Earth-size exoplanets—Kepler-62e, Kepler-62f, and Kepler-69c—in the habitable zones of their respective host stars, Kepler-62 and Kepler-69. The new exoplanets are considered prime candidates for possessing liquid water and thus a habitable environment.[148][149][150] A more recent analysis has shown that Kepler-69c is likely more analogous to Venus, and thus unlikely to be habitable.[151]
On May 15, 2013, NASA announced the spacecraft had been crippled by failure of a reaction wheel that keeps it pointed in the right direction. A second wheel had previously failed, and the spacecraft requires three wheels (out of four total) to be operational for the instrument to function properly. Further testing in July and August determined that while Kepler was capable of using its damaged reaction wheels to prevent itself from entering safe mode and of downlinking previously collected science data it was not capable of collecting further science data as previously configured.[152] Scientists working on the Kepler project said there was a backlog of data still to be looked at, and that more discoveries would be made in the following couple of years, despite the setback.[153]
Although no new science data from Kepler field had been collected since the problem, an additional sixty-three candidates were announced in July 2013 based on the previously collected observations.[154]
In November 2013, the second Kepler science conference was held. The discoveries included the median size of planet candidates getting smaller compared to early 2013, preliminary results of the discovery of a few circumbinary planets and planets in the habitable zone.[155]
2014
Histogram
of exoplanet discoveries. The yellow shaded bar shows newly announced
planets including those verified by the multiplicity technique (February
26, 2014).
On February 26, scientists announced that data from Kepler had confirmed the existence of 715 new exoplanets. A new statistical method of confirmation was used called "verification by multiplicity" which is based on how many planets around multiple stars were found to be real planets. This allowed much quicker confirmation of numerous candidates which are part of multiplanetary systems. 95% of the discovered exoplanets were smaller than Neptune and four, including Kepler-296f, were less than 2 1/2 the size of Earth and were in habitable zones where surface temperatures are suitable for liquid water.[99][157][158][159]
In March, a study found that small planets with orbital periods of less than 1 day are usually accompanied by at least one additional planet with orbital period of 1–50 days. This study also noted that ultra-short period planets are almost always smaller than 2 Earth radii unless it is a misaligned hot Jupiter.[160]
On April 17, the Kepler team announced the discovery of Kepler-186f, the first nearly Earth-sized planet located in the habitable zone. This planet orbits around a red dwarf.[161]
In May 2014, K2 observations fields 0 to 13 were announced and described in detail.[162] K2 observations began in June 2014.
In July 2014, the first discoveries from K2 field data were reported in the form of eclipsing binaries. Discoveries were derived from a Kepler engineering data set which was collected prior to campaign 0[163] in preparation to the main K2 mission.[164]
On September 23, 2014, NASA reported that the K2 mission had completed campaign 1,[165] the first official set of science observations, and that campaign 2[166] was underway.[167]
Kepler observed KSN 2011b, a Type Ia supernova, in the process of exploding: before, during and after.[168]
2015
- In January 2015, the number of confirmed Kepler planets exceeded 1000. At least two (Kepler-438b and Kepler-442b) of the discovered planets announced that month were likely rocky and in the habitable zone.[36] Also in January 2015, NASA reported that five confirmed sub-earth-sized rocky exoplanets, all smaller than the planet Venus, were found orbiting the 11.2 billion year old star Kepler-444, making this star system, at 80% of the age of the universe, the oldest yet discovered.[170][171][172]
- In April 2015, campaign 4[173] was reported to last between February 7, 2015, and April 24, 2015, and to include observations of nearly 16,000 target stars and two notable open star clusters, Pleiades and Hyades.[174]
- In May 2015, Kepler observed a newly discovered supernova, KSN 2011b (Type 1a), before, during and after explosion. Details of the pre-nova moments may help scientists better understand dark energy.[168]
- On July 24, 2015, NASA announced the discovery of Kepler-452b, a confirmed exoplanet that is near-Earth in size and found orbiting the habitable zone of a Sun-like star.[175][176] The seventh Kepler planet candidate catalog was released, containing 4,696 candidates, and increase of 521 candidates since the previous catalog release in January 2015.[177][178]
- On September 14, 2015, astronomers reported unusual light fluctuations of KIC 8462852, an F-type main-sequence star in the constellation Cygnus, as detected by Kepler, while searching for exoplanets. Various hypotheses have been presented, including comets, asteroids, and an alien civilization.[179][180][181]
2016
By May 10, 2016, the Kepler mission had verified 1,284 new planets.[37] Based on their size, about 550 could be rocky planets. Nine of these orbit in their stars' habitable zone:[37]- Kepler-560b
- Kepler-705b
- Kepler-1229b
- Kepler-1410b
- Kepler-1455b
- Kepler-1544b
- Kepler-1593b
- Kepler-1606b
- Kepler-1638b
Mission status
Kepler was launched in 2009. It was very successful at finding exoplanets, but failures in two of four reaction wheels crippled its extended mission in 2013. Without three functioning wheels, the telescope could not be pointed accurately. On October 30, 2018, NASA announced that the spacecraft was out of fuel and its mission was officially ended. [182]Extension
Predicted structure of the Milky Way overlaid with the original Kepler search space.[5]
Reaction wheel issues
In July 2012, one of Kepler's four reaction wheels (wheel 2) failed.[20] On May 11, 2013, a second wheel (wheel 4) failed, jeopardizing the continuation of the mission, as three wheels are necessary for its planet hunting.[18][19] Kepler had not collected science data since May because it was not able to point with sufficient accuracy.[145] On July 18 and 22 reaction wheels 4 and 2 were tested respectively; wheel 4 only rotated counter-clockwise but wheel 2 ran in both directions, albeit with significantly elevated friction levels.[185] A further test of wheel 4 on July 25 managed to achieve bi-directional rotation.[186] Both wheels, however, exhibited too much friction to be useful.[22] On August 2, NASA put out a call for proposals to use the remaining capabilities of Kepler for other scientific missions. Starting on August 8, a full systems evaluation was conducted. It was determined that wheel 2 could not provide sufficient precision for scientific missions and the spacecraft was returned to a "rest" state to conserve fuel.[20] Wheel 4 was previously ruled out because it exhibited higher friction levels than wheel 2 in previous tests.[186] Sending astronauts to fix Kepler is not an option because it orbits the Sun and is millions of kilometers from Earth.[22]On August 15, 2013, NASA announced that Kepler would not continue searching for planets using the transit method after attempts to resolve issues with two of the four reaction wheels failed.[20][21][22] An engineering report was ordered to assess the spacecraft's capabilities, its two good reaction wheels and its thrusters.[20] Concurrently, a scientific study was conducted to determine whether enough knowledge can be obtained from Kepler's limited scope to justify its $18 million per year cost.
Possible ideas included searching for asteroids and comets, looking for evidence of supernovas, and finding huge exoplanets through gravitational microlensing.[22] Another proposal was to modify the software on Kepler to compensate for the disabled reaction wheels. Instead of the stars being fixed and stable in Kepler's field of view, they will drift. However, proposed software was to track this drift and more or less completely recover the mission goals despite being unable to hold the stars in a fixed view.[187]
Previously collected data continues to be analyzed.[188]
Second Light (K2)
In November 2013, a new mission plan named K2 "Second Light" was presented for consideration.[25][26][27][189] K2 would involve using Kepler's remaining capability, photometric precision of about 300 parts per million, compared with about 20 parts per million earlier, to collect data for the study of "supernova explosions, star formation and Solar-System bodies such as asteroids and comets, ... " and for finding and studying more exoplanets.[25][26][189] In this proposed mission plan, Kepler would search a much larger area in the plane of Earth's orbit around the Sun.[25][26][189]In early 2014, the spacecraft underwent successful testing for the K2 mission.[191] From March to May 2014, data from a new field called Field 0 was collected as a testing run.[192] On May 16, 2014, NASA announced the approval of extending the Kepler mission to the K2 mission.[28] Kepler's photometric precision for the K2 mission was estimated to be 50 ppm on a magnitude 12 star for a 6.5-hour integration.[193] In February 2014, photometric precision for the K2 mission using two-wheel, fine-point precision operations was measured as 44 ppm on magnitude 12 stars for a 6.5-hour integration. The analysis of these measurements by NASA suggests the K2 photometric precision approaches that of the Kepler archive of three-wheel, fine-point precision data.[194]
On May 29, 2014, campaign fields 0 to 13 were reported and described in detail.[162]
K2 proposal explained (December 11, 2013).[26]
On December 18, 2014, NASA announced that the K2 mission had detected its first confirmed exoplanet, a super-Earth named HIP 116454 b. Its signature was found in a set of engineering data meant to prepare the spacecraft for the full K2 mission. Radial velocity follow-up observations were needed as only a single transit of the planet was detected.[199]
During a scheduled contact on April 7, 2016, Kepler was found to be operating in emergency mode, the lowest operational and most fuel intensive mode. Mission operations declared a spacecraft emergency, which afforded them priority access to NASA's Deep Space Network.[200][201] By the evening of April 8 the spacecraft had been upgraded to safe mode, and on April 10 it was placed into point-rest state,[202] a stable mode which provides normal communication and the lowest fuel burn.[200] At that time, the cause of the emergency was unknown, but it was not believed that Kepler's reaction wheels or a planned maneuver to support K2's Campaign 9 were responsible. Operators downloaded and analyzed engineering data from the spacecraft, with the prioritization of returning to normal science operations.[200][203] Kepler was returned to science mode on April 22.[204] The emergency caused the first half of Campaign 9 to be shortened by two weeks.[205]
In June 2016, NASA announced a K2 mission extension of three additional years, beyond the expected exhaustion of on-board fuel in 2018.[206] In August 2018, NASA roused the spacecraft from sleep mode, applied a modified configuration to deal with thruster problems that degraded pointing performance, and began collecting scientific data for the 19th observation campaign, finding that the onboard fuel was not yet utterly exhausted.[207]
Data releases
The Kepler team originally promised to release data within one year of observations.[208] However, this plan was changed after launch, with data being scheduled for release up to three years after its collection.[209] This resulted in considerable criticism,[210][211][212][213][214] leading the Kepler science team to release the third quarter of their data one year and nine months after collection.[215] The data through September 2010 (quarters 4, 5, and 6) was made public in January 2012.[216]Follow-ups by others
Periodically, the Kepler team releases a list of candidates (Kepler Objects of Interest, or KOIs) to the public. Using this information, a team of astronomers collected radial velocity data using the SOPHIE échelle spectrograph to confirm the existence of the candidate KOI-428b in 2010, later named Kepler-40b.[217] In 2011, the same team confirmed candidate KOI-423b, later named Kepler-39b.[218]Citizen scientist participation
Since December 2010, Kepler mission data has been used for the Planet Hunters project, which allows volunteers to look for transit events in the light curves of Kepler images to identify planets that computer algorithms might miss.[219] By June 2011, users had found sixty-nine potential candidates that were previously unrecognized by the Kepler mission team.[220] The team has plans to publicly credit amateurs who spot such planets.In January 2012, the BBC program Stargazing Live aired a public appeal for volunteers to analyse Planethunters.org data for potential new exoplanets. This led two amateur astronomers—one in Peterborough, England—to discover a new Neptune-sized exoplanet, to be named Threapleton Holmes B.[221] One hundred thousand other volunteers were also engaged in the search by late January, analyzing over one million Kepler images by early 2012.[222] One such exoplanet, PH1b (or Kepler-64b from its Kepler designation), was discovered in 2012. A second exoplanet, PH2b (Kepler-86b) was discovered in 2013.
In April 2017, ABC Stargazing Live, a variation of BBC Stargazing Live, launched the Zooniverse project "Exoplanet Explorers". While Planethunters.org worked with archived data, Exoplanet Explorers used recently downlinked data from the K2 mission. On the first day of the project, 184 transit candidates were identified that passed simple tests. On the second day, the research team identified a star system, later named K2-138, with a Sun-like star and four super-Earths in a tight orbit. In the end, volunteers helped to identify 90 exoplanet candidates.[223][224] The citizen scientists that helped discover the new star system will be added as co-authors in the research paper when published.[225]
Confirmed exoplanets
Confirmed small exoplanets in habitable zones (Kepler-62e, Kepler-62f, Kepler-186f, Kepler-296e, Kepler-296f, Kepler-438b, Kepler-440b, Kepler-442b).[36]
Both Corot[233] and Kepler[106] measured the reflected light from planets. However, these planets were already known, because they transit their star. Kepler's data allowed the first discovery of planets by this method, Kepler-70b and Kepler-70c.[234]
Kepler Input Catalog
The Kepler Input Catalog is a publicly searchable database of roughly 13.2 million targets used for the Kepler Spectral Classification Program and the Kepler mission.[235][236] The catalog alone is not used for finding Kepler targets, because only a portion of the listed stars (about one-third of the catalog) can be observed by the spacecraft.[235]Solar System observations
Kepler has been assigned an observatory code (C55) in order to report its astrometric observations of small Solar System bodies to the Minor Planet Center. In 2013 the alternative NEOKepler mission was proposed, a search for near-Earth objects, in particular potentially hazardous asteroids (PHAs). Its unique orbit and larger field of view than existing survey telescopes allow it to look for objects inside Earth's orbit. It was predicted a 12-month survey could make a significant contribution to the hunt for PHAs as well as potentially locating targets for NASA's Asteroid Redirect Mission.[237] Kepler's first discovery in the Solar System, however, was (506121) 2016 BP81, a 200-kilometer cold classical Kuiper belt object located beyond the orbit of Neptune.[238]Retirement
See also
- Kepler-22b, the first exoplanet confirmed by Kepler to have an average orbital distance within its star's habitable zone
- List of exoplanets discovered using the Kepler spacecraft
- List of exoplanets
- List of multiplanetary systems
- Hunt for Exomoons with Kepler
- William J. Borucki, the chief investigator for Kepler
- NASA Exoplanet Archive, online exoplanet catalog
Johannes Kepler was a German mathematician, astronomer, and astrologer. Kepler is a key figure in the 17th-century scientific revolution. He is best known for ...
Influences: Nicolaus Copernicus; Tycho Brahe
Known for: Kepler's laws of planetary motion; ...
Influenced: Sir Isaac Newton
Nationality: German
Oct 29, 2018 - Johannes Kepler, (born December 27, 1571, Weil der Stadt, Württemberg [
Johannes Kepler is now chiefly remembered for discovering the three laws of planetary motion that bear his name published in 1609 and 1619). He also did ...
People also ask
Web results
Nov 20, 2017 - When Johannes Kepler was born in the late 16th century, people thought that planets in the solar system traveled in circular orbits around Earth ...
Johannes Kepler was born about 1 PM on December 27, 1571, in Weil der Stadt, Württemberg, in the Holy Roman Empire of German Nationality. He was a ...
Johannes Kepler was an astronomer around the same time as Galileo. He was a heliocentrist, and he made great contributions to the telescope and astronomy.
Johannes Kepler was one of the great astronomers of the 17th century. Kepler was born in Weil der Stadt in southern Germany on 27 December 1571. His father ...
Johannes Kepler played a key role in the profound changes in human thinking that took place during the the scientific revolution. In Kepler's lifetime:.
Johannes Kepler based on his science on the Bible.
The German astronomer Johannes Kepler's discovery of three basic laws governing the motion of planets made him one of the chief founders of modern ...
Complementary results
Knowledge result
Johannes Kepler was a German mathematician, astronomer, and astrologer. Kepler is a key figure in the 17th-century scientific revolution. He is best known for his laws of planetary motion, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican Astronomy. Wikipedia
Born: 27 December 1571, Weil der Stadt, Germany
Died: 15 November 1630, Regensburg, Germany
Education: University of Tübingen (1591–1594), MORE
I much prefer the sharpest criticism of a single intelligent man to the thoughtless approval of the masses.
Nature uses as little as possible of anything.
Truth is the daughter of time, and I feel no shame in being her midwife.
Subscribe to:
Posts (Atom)