terça-feira, 28 de março de 2017

Chuva de meteoros Liríadas 22 de abril de 2017




No início do Outono no hemisfério sul começa a Temporada das Grandes Chuvas de Meteoros no Brasil.

A chuva de Meteoros Lirídeos ou Lirídas (006 LYR) está associada ao cometa C/1861 G1 (Thatcher) e é visível anualmente entre os dias 16 a 25 de abril.

A atividade é máxima no ano de 2017 é no dia 22 de abril (Feriadão de Tiradentes) quando poderão ser observados até 18 meteoros por hora com a constelação de Lira no zênite (em cima de sua cabeça). 

Seu Radiante (de onde irão surgir os meteoros) se encontra próximo da estrela Vega (Alpha Lyrae), a estrela mais brilhante da constelação da Lira que está visível ao norte no início da madrugada de outono.

A constelação de Lira é melhor observada nas regiões norte e nordeste, mas é visível em todo o Brasil, sempre de madrugada nesta época do ano.

No dia do Pico, 22 de abril, a Lua estará em Fase Minguante e com luz cinérea, iluminada somente 22%, interferindo pouco na observação dos Lirídeos em 2017.

O meteoros Lirídeos entram na atmosfera da Terra a 49 km/s ou 176.400 km/h.

O mais antigo registro de observações dessa Chuva de Meteoros remonta ao ano 687 a.C. e há ainda um registro dos astrônomos chineses de que no ano 15 a.C. essa chuva de meteoros Lirídeos foi particularmente notável. Esta é uma chuva que pode ter surpresas na taxa horária, podendo chegar a 90 meteoros/hora em 2017, conforme informações do IMO.

Em 1835, a Chuva de Meteoros Lirídeos foi reconhecida cientificamente e ela está associada ao cometa C/1861 G1 (Thatcher).

Na mesma época da Chuva Lirídeos (006 LYR) acontece a Chuva de Meteoros Pi-Pupideos (137 PPU) e estaremos no início da atividade da Chuva de Meteoros Eta-Aquarídeos (031 ETA), uma das mais famosas chuva de meteoros.

A chuva de meteoros Pi-Pupídeos, por vezes é referido apenas como Pupídeos ou Pupidas e a janela de observação está entre os dias 15 a 28 de Abril, com o pico no dia 23 de abril de 2017 (Domingo, no final do Feriadão de Tiradentes).

Seu radiante está localizado próximo da estrela π (pi) Puppis na constelação da Popa e a chuva está associada ao cometa 26P/Grigg-Skjellerup, resultando em meteoros lentos, entrando na atmosfera a 18 km/s ou 64.800 km/h.

A atividade da chuva Pi-Pupídeos somente foi detectada em 1972.

Neste ano de 2017, a previsão é variável, podendo a chegar a até 40 meteoros/hora e a Lua não irá interferir na observação.

A constelação da Popa, onde está o radiante da chuva de meteoros Pi-Pupídeos é fácil de localizar pois está entre as brilhantes estrelas Sirius (Alpha Canis Majoris) e Canopus (Alpha Carinae), as duas estrelas mais brilhantes do céu noturno, visíveis a sudoeste no início da noite nesta época do ano.

A Chuva de meteoros Pi-Pupideos pode ser observada no início da noite até o início da madrugada a sudoeste (SO), neste momento começam a ser observados os Meteoros das Liríadas, ao norte.

Talvez você observe algum meteoro da Chuva de Meteoros Eta-Aquarídeos (031 ETA), relacionada com o famoso Cometa Halley.

A Eta-Aquarídeos está ativa do dia 19 de abril ao dia 28 de maio, com o pico no dia 6 de maio.

A constelação de Aquário, de onde surgem os meteoros do cometa Halley surge a leste no nordeste/norte do Brasil no início da madrugada e é visível até o final da madrugada, sendo o melhor horário de observação 2 horas antes do nascer do Sol.

Todo o Brasil pode observar esta chuva, mas o nordeste e o norte do Brasil são os melhores locais de observação, com constelação de Aquário mais alta no céu.

A Chuva de meteoros Liríadas é observada durante a madrugada.

No mês de Abril, é comemorado o GAM (Global Astronomy Month) ou Mês Global da Astronomia, com diversas atividades de observação em todo o mundo !

Fique atento as informações dos Grupos e Clubes de Astronomia de sua cidade e região.

O Feriado de Tiradentes de 2017 no Brasil será Meteorítico !

E o ano de 2017 promete ser Excelente para a observação das Chuvas de Meteoros !



Agora é Curtir as Chuvas de Meteoros de 2017 !



Mais informações:
https://www.facebook.com/OQueVerNoCeuAstronomia/photos/a.331943486984502.1073741828.331852660326918/703071966538317/?type=3&theater


Boas observações dos Meteoros.

Un telescopio grande quanto la Terra per fotografare un buco nero

Da Ansa.it - Al nastro di partenza una delle più grandi imprese astronomiche di tutti i tempi: osservare e fotografare per la prima volta dalla Terra corpi celesti 'irraggiungibili' come i buchi neri. Il progetto, descritto sul sito di Nature, si chiama Event Horizon Telescope (Eht) e punta a unire le forze di otto dei più grandi radiotelescopi del mondo per creare un radiotelescopio delle dimensioni della Terra. 

Le prime osservazioni sono previste in aprile, ma l'elaborazione dei dati richiederà tempo, al punto che la prima foto è attesa nel 2018. Diretto da Sheperd Doeleman, dell'università americana di Harvard, il progetto mira a fotografare sia il buco nero al centro della Via Lattea, che ha una massa pari a 4 milioni di volte quella del Sole, sia il buco nero al centro della galassia M87, che ha una massa di circa 6 miliardi quella del Sole. 

Della rete dei radiotelescopi coinvolti fanno parte Alma (Cile), Iram (Spagna) e il South Pole Telescope (Antartide) e tutti punteranno le antenne contemporaneamente verso lo stesso obiettivo per osservare la materia che ruota intorno al buco nero prima che oltrepassi l'orizzonte degli eventi, ossia il 'punto di non ritorno' oltre il quale la gravità è così forte che nulla di ciò che lo attraversa può fuggire. 

I risultati delle osservazioni permetteranno anche di sottoporre a uno dei test più rigorosi la teoria della relatività di Einstein e di scoprire come nascono i getti ad altissima energia emessi dai buchi neri. Gli obiettivi sono ambiziosi quanto sarà complesso, per gli otto radiotelescopi, riuscire a catturare le immagini contemporaneamente. Uno dei vincoli è che ognuno dovrà avere cieli cristallini e di conseguenza la rete potrà funzionare solo per due settimane l'anno.

L'atmosfera del Sole è 'irrequieta' come quella della Terra

Da Ansa.it - L'atmosfera del Sole è irrequieta come quella terrestre: al suo interno sono infatti riconoscibili delle enormi 'onde' che si propagano in maniera simile a quelle che condizionano il meteo sul nostro Pianeta. La scoperta è pubblicata su Nature Astronomy dal Centro statunitese per gli studi atmosferici (Ncar) con il supporto della Nasa, e in futuro potrà aiutare a prevedere la formazione di macchie ed eruzioni solari, così come le tempeste magnetiche che spesso colpiscono la Terra interferendo con satelliti, comunicazioni e reti elettriche. 

Le onde magnetiche nell'atmosfera del Sole, simili alle cosiddette 'onde di Rossby' che condizionano il meteo sulla Terra, sono state individuate grazie all'azione congiunta di tre strumenti della Nasa, ovvero l'osservatorio solare Sdo (Solar Dynamics Observatory) e le due sonde gemelle della missione Stereo (Solar TErrestrial RElations Observatory). 

I dati raccolti tra il 2011 e il 2014 (cioè fino a quando si è persa una delle sonde Stereo) hanno permesso per la prima volta di avere una visione completa del Sole a 360 gradi, facilitando l'individuazione delle onde. ''La scoperta - spiegano gli esperti - potrebbe rivelarsi molto utile per la previsione delle tempeste solari, il 'motore' del meteo spaziale che condiziona anche la Terra. Il 'cattivo tempo' nello spazio può infatti interferire con i satelliti, i sistemi di comunicazione e navigazione, così come può causare balckout elettrici, determinando importanti costi socio-economici che si stimano pari a circa 10 miliardi di dollari all'anno''. Per capire come le onde dell'atmosfera solare influiscano su scala locale ''dobbiamo ancora ampliare la visuale'', precisano i ricercatori. ''Avremmo bisogno di una costellazione di veicoli spaziali che ruoti intorno al Sole per monitorare l'evoluzione del suo campo magnetico globale''.

Planet Again? Pluto, Most Moons Count Under Proposed Definition

By 

The geophysical definition of a planet categorizes the worlds of the solar system by their composition. Rather than remembering the individual planets, students would learn about the types.

Credit: Kirby Runyon, et al.


The geophysical definition of a planet categorizes the worlds of the solar system by their composition. Rather than remembering the individual planets, students would learn about the types.

Credit: Kirby Runyon, et al.

THE WOODLANDS, Texas — There's new hope for people who still believe that Pluto is a planet more than a decade after the International Astronomical Union (IAU) reclassified the object as a dwarf planet. 
A group of planetary scientists is making the case that the definition for a planet should rely more on what an object is than where it is. Pluto's demotion came largely because the world fails to clear its orbit of other large objects (most notably, Neptune). But the proposed geophysical definition focuses on the physical properties of a body rather than the characteristics of its orbit, and would also include objects such as the dwarf planet Ceres and Jupiter's moon Europa.
"The [current] IAU definition [of a planet] is primarily concerned with gravitational perturbations and orbits," Kirby Runyon, a planetary scientist graduate student at Johns Hopkins University told Space.com. "Those aren't what planetary scientists study." [Destination Pluto: NASA's New Horizons Mission in Pictures]

www.space.com

Solar eclipse


www.space.com

segunda-feira, 27 de março de 2017

Lua de Júpiter vira aposta de cientistas na busca por vida extraterrestre no Sistema Solar





Checking in on Bleriot

What appears as a pair of bright dashes at the center of this image is one of the features rings scientists have dubbed "propellers." This particular propeller, named Bleriot, marks the presence of a body that is much larger than the particles that surround it, yet too small to clear out a complete gap in the rings (like Pan and Daphnis) and become a moon in its own right. Although the moonlet at the core of the propeller is itself too small to see, the disturbances in the rings caused by its gravity betray its presence.
Cassini scientists have been tracking propeller features like this one for years in order to learn how their orbits change over time. From this, they hope to gain insight into how forming planets migrate in the disks in which they form.
For more on Bleriot, see PIA12792.
This view looks toward the sunlit side of the rings from about 59 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 9, 2017.
The view was acquired at a distance of approximately 223,000 miles (359,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 73 degrees. Image scale is 1.2 miles (2 kilometers) per pixel.
The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.
For more information about the Cassini-Huygens mission visit  http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org .
Credit: NASA/JPL-Caltech/Space Science Institute
Last Updated: March 27, 2017
Editor: Martin Perez

A supermassive black hole inside a tiny galaxy is challenging scientists' ideas about what happens when two galaxies become one.

This optical image shows the Was 49 system, which consists of a large disk galaxy, Was 49a, merging with a much smaller "dwarf" galaxy Was 49b.
Credits: DCT/NRL
A supermassive black hole inside a tiny galaxy is challenging scientists' ideas about what happens when two galaxies become one.
Was 49 is the name of a system consisting of a large disk galaxy, referred to as Was 49a, merging with a much smaller "dwarf" galaxy called Was 49b. The dwarf galaxy rotates within the larger galaxy's disk, about 26,000 light-years from its center. Thanks to NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) mission, scientists have discovered that the dwarf galaxy is so luminous in high-energy X-rays, it must host a supermassive black hole much larger and more powerful than expected.
"This is a completely unique system and runs contrary to what we understand of galaxy mergers," said Nathan Secrest, lead author of the study and postdoctoral fellow at the U.S. Naval Research Laboratory in Washington.
Data from NuSTAR and the Sloan Digital Sky Survey suggest that the mass of the dwarf galaxy's black hole is huge, compared to similarly sized galaxies, at more than 2 percent of the galaxy's own mass.
"We didn't think that dwarf galaxies hosted supermassive black holes this big," Secrest said. "This black hole could be hundreds of times more massive than what we would expect for a galaxy of this size, depending on how the galaxy evolved in relation to other galaxies.”
The dwarf galaxy's black hole is the engine of an active galactic nucleus (AGN), a cosmic phenomenon in which extremely high-energy radiation bursts forth as a black hole devours gas and dust. This particular AGN appears to be covered by a donut-shaped structure made of gas and dust. NASA's Chandra and Swift missions were used to further characterize the X-ray emission.
Normally, when two galaxies start to merge, the larger galaxy's central black hole becomes active, voraciously gobbling gas and dust, and spewing out high-energy X-rays as matter gets converted into energy. That is because, as galaxies approach each other, their gravitational interactions create a torque that funnels gas into the larger galaxy's central black hole. But in this case, the smaller galaxy hosts a more luminous AGN with a more active supermassive black hole, and the larger galaxy's central black hole is relatively quiet.
An optical image of the Was 49 system, compiled using observations from the Discovery Channel Telescope in Happy Jack, Arizona, uses the same color filters as the Sloan Digital Sky Survey. Since Was 49 is so far away, these colors are optimized to separate highly-ionized gas emission, such as the pink-colored region around the feeding supermassive black hole, from normal starlight, shown in green. This allowed astronomers to more accurately determine the size of the dwarf galaxy that hosts the supermassive black hole.
The pink-colored emission stands out in a new image because of the intense ionizing radiation emanating from the powerful AGN. Buried within this region of intense ionization is a faint collection of stars, believed to be part of the galaxy surrounding the enormous black hole. These striking features lie on the outskirts of the much larger spiral galaxy Was 49a, which appears greenish in the image due to the distance to the galaxy and the optical filters used. 
Scientists are still trying to figure out why the supermassive black hole of dwarf galaxy Was 49b is so big. It may have already been large before the merger began, or it may have grown during the very early phase of the merger. 
"This study is important because it may give new insight into how supermassive black holes form and grow in such systems," Secrest said. “By examining systems like this, we may find clues as to how our own galaxy’s supermassive black hole formed.”
In several hundred million years, the black holes of the large and small galaxies will merge into one enormous beast. 
NuSTAR is a Small Explorer mission led by Caltech and managed by JPL for NASA's Science Mission Directorate in Washington. NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corp., Dulles, Virginia. NuSTAR's mission operations center is at UC Berkeley, and the official data archive is at NASA's High Energy Astrophysics Science Archive Research Center. ASI provides the mission's ground station and a mirror archive. JPL is managed by Caltech for NASA.
For more information on NuSTAR, visit:
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov
2017-088

sábado, 25 de março de 2017

2017 Full Moon Calendar


Many cultures have given distinct names to each recurring full moon. The names were applied to the entire month in which each occurred. The Farmer's Almanac lists several names that are commonly used in the United States. The almanac explains that there were some variations in the moon names, but in general, the same ones were used among the Algonquin tribes from New England on west to Lake Superior. European settlers followed their own customs and created some of their own names.
This is when full moons will occur in 2017, according to NASA:
DateNameU.S. EastUTC
Jan. 12Wolf Moon6:34 a.m.11:34
Feb. 10Snow Moon7:33 p.m.00:33 (2/11)
Mar. 12Worm Moon10:54 a.m.15:54
Apr. 11Pink Moon2:08 a.m.07:08
May 10Flower Moon5:43 p.m.22:43
June 9Strawberry Moon9:10 a.m.14:10
July 9Buck Moon12:07 a.m.05:07
Aug. 7Sturgeon Moon2:11 p.m.19:11
Sept. 6Harvest Moon3:03 a.m.08:03
Oct. 5Hunter's Moon2:40 p.m.19:40
Nov. 4Beaver Moon12:23 a.m.05:23
Dec. 3Cold Moon10:47 a.m.15:47
Other Native American people had different names. In the book "This Day in North American Indian History" (Da Capo Press, 2002), author Phil Konstantin lists more than 50 native peoples and their names for full moons. He also lists them on his website, AmericanIndian.net.
Amateur astronomer Keith Cooley has a brief list of the moon names of other cultures, including Chinese and Celtic, on his website. For example:
Chinese moon names
MonthNameMonthName
JanuaryHoliday MoonJulyHungry Ghost Moon
FebruaryBudding MoonAugustHarvest Moon
MarchSleepy MoonSeptemberChrysanthemum Moon
AprilPeony MoonOctoberKindly Moon
MayDragon MoonNovemberWhite Moon
JuneLotus MoonDecemberBitter Moon
Full moon names often correspond to seasonal markers, so a Harvest Moon occurs at the end of the growing season, in September, and the Cold Moon occurs in frosty December. At least, that's how it works in the Northern Hemisphere.
In the Southern Hemisphere, where the seasons are switched, the Harvest Moon occurs in March and the Cold Moon is in June. According to Earthsky.org, these are common names for full moons south of the equator.
January: Hay Moon, Buck Moon, Thunder Moon, Mead Moon
February (mid-summer): Grain Moon, Sturgeon Moon, Red Moon, Wyrt Moon, Corn Moon, Dog Moon, Barley Moon
March: Harvest Moon, Corn Moon
April: Harvest Moon, Hunter’s Moon, Blood Moon
May: Hunter’s Moon, Beaver Moon, Frost Moon
June: Oak Moon, Cold Moon, Long Night’s Moon
July: Wolf Moon, Old Moon, Ice Moon
August: Snow Moon, Storm Moon, Hunger Moon, Wolf Moon
September: Worm Moon, Lenten Moon, Crow Moon, Sugar Moon, Chaste Moon, Sap Moon
October: Egg Moon, Fish Moon, Seed Moon, Pink Moon, Waking Moon
November: Corn Moon, Milk Moon, Flower Moon, Hare Moon
December: Strawberry Moon, Honey Moon, Rose Moon

Here's how a full moon works:
The moon is a sphere that travels once around Earth every 27.3 days. It also takes about 27 days for the moon to rotate on its axis. So, the moon always shows us the same face; there is no single "dark side" of the moon. As the moon revolves around Earth, it is illuminated from varying angles by the sun — what we see when we look at the moon is reflected sunlight. On average, the moon rises about 50 minutes later each day, which means sometimes it rises during daylight and other times during nighttime hours.
Here’s how the moon's phases go:
At new moon, the moon is between Earth and the sun, so that the side of the moon facing toward us receives no direct sunlight, and is lit only by dim sunlight reflected from Earth.
A few days later, as the moon moves around Earth, the side we can see gradually becomes more illuminated by direct sunlight. This thin sliver is called the waxing crescent.
A week after new moon, the moon is 90 degrees away from the sun in the sky and is half-illuminated from our point of view, what we call first quarterbecause it is about a quarter of the way around Earth.
A few days later, the area of illumination continues to increase. More than half of the moon's face appears to be getting sunlight. This phase is called a waxing gibbous moon.
When the moon has moved 180 degrees from its new moon position, the sun, Earth and the moon form
From www.space.com








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