понедельник, 16 декабря 2019 г.

Interstellar Comet 2I/Borisov Swings Past the Sun

Comet 2I/Borisov Near and at Perihelion
Credits: NASA, ESA, and D. Jewitt (UCLA)

These two images, taken by NASA's Hubble Space Telescope, capture comet 2I/Borisov streaking though our solar system and on its way back to interstellar space. It is only the second interstellar object known to have passed through the solar system.

"Hubble gives us the best upper limit of the size of comet Borisov's nucleus, which is the really important part of the comet," said David Jewitt, a UCLA professor of planetary science and astronomy, whose team has captured the best and sharpest look at this first confirmed interstellar comet. "Surprisingly, our Hubble images show that its nucleus is more than 15 times smaller than earlier investigations suggested it might be. Our Hubble images show that the radius is smaller than half-a-kilometer. Knowing the size is potentially useful for beginning to estimate how common such objects may be in the solar system and our galaxy. Borisov is the first known interstellar comet, and we would like to learn how many others there are."

Crimean amateur astronomer Gennady Borisov discovered the comet on August 30, 2019 and reported the position measurements to the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts. The Center for Near-Earth Object Studies at the Jet Propulsion Laboratory, working with the Minor Planet Center, computed an orbit for the comet which shows that it came from elsewhere in our Milky Way galaxy, point of origin unknown.

Nevertheless, observations by numerous telescopes show that the comet's chemical composition is similar to the comets found inside our solar system, providing evidence that comets also form around other stars. By the middle of 2020 the comet will have already zoomed past Jupiter's distance of 500 million miles on its way back into the frozen abyss of interstellar space.

[left] November 16, 2019 photo

The comet appears in front of a distant background spiral galaxy (2MASX J10500165-0152029). The galaxy's bright central core is smeared in the image because Hubble was tracking the comet. Comet Borisov was approximately 203 million miles from Earth in this exposure. Its tail of ejected dust streaks off to the upper right. The comet has been artificially colored blue to discriminate fine detail in the halo of dust, or coma, surrounding the central nucleus. It also helps to visually separate the comet from the background galaxy.

[right] December 9, 2019 photo

Hubble revisited the comet shortly after its closest approach to the Sun where it received maximum heating after spending most of its life in frigid interstellar space. The comet also reached a breathtaking maximum speed of about 100,000 miles per hour. Comet Borisov is 185 million miles from Earth in this photo, near the inner edge of the asteroid belt but below it. The nucleus, an agglomeration of ices and dust, is still too small to be resolved. The bright central portion is a coma made up of dust leaving the surface. The comet will make its closest approach to Earth in late December at a distance of 180 million miles.

The Hubble Space Telescope is a project of international cooperation between the European Space Agency (ESA) and NASA. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C. The Minor Planet Center and the Center for Near-Earth Orbit Studies are projects of NASA’s Near-Earth Object Observations Program of the Planetary Defense Coordination Office at NASA Headquarters.




Contact

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4514
villard@stsci.edu

Stuart Wolpert
UCLA, Los Angeles, California
swolpert@stratcomm.ucla.edu

David Jewitt
UCLA, Los Angeles, California
jewitt@ucla.edu



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* This article was originally published here

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Massive UFO Seen In California!

358 views   43 likes   2 dislikes  

Channel: Terry's Theories  

Massive UFO hovering over California or is it. Tell me what you guys think. So here is the backstory. This was supposedly recorded a day or two ago and when the authorities approached this object took off wish that was on the video but its not. So tell me what we are looking at. Is this the real deal or are we looking at skydivers or some other natural event.
Source video: https://www.youtube.com/watch?v=7f830n4DD3I

Video length: 2:41
Category: Science & Technology
40 comments

Radio Jupiter: Seeing the Giant Planet in a New Light

Radio image of Jupiter made with ALMA. Bright bands indicate high temperatures and dark bands low temperatures. The dark bands correspond to the zones on Jupiter, which are often white at visible wavelengths. The bright bands correspond to the brown belts on the planet. This image contains over 10 hours of data, so fine details are smeared by the planet's rotation. Credit: ALMA (ESO/NAOJ/NRAO), I. de Pater et al.; NRAO/AUI NSF, S. Dagnello

Flat map of Jupiter in radio waves with ALMA (top) and visible light with the Hubble Space Telescope (bottom). The eruption in the South Equatorial Belt is visible in both images. Credit: ALMA (ESO/NAOJ/NRAO), I. de Pater et al.; NRAO/AUI NSF, S. Dagnello; NASA/Hubble. Hi-res image

Burke and Franklin's antenna array.
Credit: Carnegie Institution of Washington. Hi-res image

Radio image (bottom) captured by the VLA of Jupiter's Great Red Spot, compared with a visible-light image (top) from the Hubble Space Telescope. Credit: de Pater, et al., NRAO/AUI/NSF; NASA. Hi-res image

A 2003 image of Jupiter. The lobes on each side of the planet are caused by Jupiter's strong magnetosphere.
Credit: NRAO/AUI/NSF. Hi-res image



Jupiter is the largest planet in our solar system. It is also the brightest planet at radio frequencies. While radio astronomy often focuses on more distant objects such as nebulae and galaxies, the radio astronomy of planets begins with Jupiter.

While other planets in our solar system emit radio light, Jupiter is by far the most radio bright. When charged particles in space interact with Jupiter’s magnetic field, they emit radio light through a process known as synchrotron radiation. The first radio observation of Jupiter was made by Bernard Burke and Kenneth Franklin in 1955. They weren’t expecting such a signal, so they initially thought it was the radio noise of a farm-hand driving home. But subsequent observations showed the signal was Jovian in origin.

In addition to its synchrotron emissions, Jupiter also gives off radio light due to thermal emissions. These fainter emissions were first mapped by the Very Large Array (VLA). The VLA’s antennas can work together in a wide configuration to capture faint and high-resolution radio images.

When the VLA was upgraded in 2011, it greatly increased its sensitivity and imaging capabilities. In 2013 the VLA gathered the first radio images of Jupiter’s atmosphere. It allowed us to peer into Jupiter’s thick atmosphere. Observations in visible light are limited by the cloud layer of Jupiter. But radio light penetrates these cloud layers more easily. The VLA observations let us see 100 kilometers below the visible clouds. They captured details of the great red spot, and how ammonia within Jupiter’s cloud layer rises and falls.

Recently the Atacama Large Millimeter/submillimeter Array (ALMA) also captured even higher resolution images of Jupiter’s thermal emissions. ALMA operates at shorter wavelengths than the VLA. Since shorter wavelengths are absorbed more readily by Jupiter’s atmosphere, ALMA’s observation only penetrates about 50 kilometers below Jupiter’s cloud layer. But ALMA’s high resolution allowed astronomers to create a three-dimensional map of ammonia gas within the atmosphere. This helps us understand the mechanisms that drive storms on Jupiter.

As radio technology has advanced, the radio astronomy of Jupiter has become much more accessible. With only modest radio equipment, you can observe the radio light of Jupiter for yourselves. Projects such as NASA’s Radio JOVE encourage students and amateur scientists to observe radio emissions from Jupiter and other bright radio sources. The project teaches students about radio astronomy and engages in citizen science research projects.

Jupiter has long inspired humanity to look toward the stars. From Galileo’s first view through his telescope, to the radio arrays of the VLA and ALMA, the light of Jupiter at all wavelengths has much to offer.




Reference: de Pater, Imke, et al. “Peering through Jupiter’s clouds with radio spectral imaging.” Science 352.6290 (2016): 1198-1201.

Reference: de Pater, Imke, et al. “First ALMA Millimeter-wavelength Maps of Jupiter, with a Multiwavelength Study of Convection.” The Astronomical Journal 158.4 (2019): 139.




* This article was originally published here

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