Дата: 01 апреля 1998 (1998-04-01)
От: Alexander Bondugin
Тема: A Bull's Eye For MERLIN and Hubble
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University of Manchester
Nuffield Radio Astronomy Laboratories
Jodrell Bank
Macclesfield
Cheshire SK11 9DL
England
PRESS RELEASE: PR9801 27th March 1998
A Bull's Eye for MERLIN and the Hubble
A team of British astronomers using the UK's MERLIN radio array and the
Hubble Space Telescope have found an ``Einstein Ring'' -- a gravitational
effect predicted by Albert Einstein over 60 years ago as a consequence of
his General Theory of Relativity. The Hubble picture is a beautiful
demonstration of Einstein's ideas since, for the first time, it shows a
complete ring surrounding the galaxy that created it.
The effect is a cosmic mirage caused by the gravity of a massive galaxy
bending the light from an object behind it and acting as a ``gravitational
lens''. On the rare occasions when the distant object, the lens galaxy and
the telescope are exactly aligned an ``Einstein ring'' is created.
Dr. Ian Browne of the University of Manchester admits ``At first sight
it looks artificial and we thought it was some sort of defect in the
image but then we realised we were actually looking at a perfect
Einstein ring!''.
Commenting later on the pictures Bristol University astronomer Professor
Mark Birkinshaw said ``MERLIN and the Hubble have scored a bulls-eye!''.
The size of the ring on the sky is tiny -- roughly a second of arc or about
the size of a penny viewed from a distance of over two miles -- even though
the lens consists of an entire galaxy. The blurring effect of the atmosphere
makes such fine detail hard for astronomers to spot using optical telescopes
on the Earth.
The British team found it by using the 135 mile-wide MERLIN radio telescope
to image distant radio sources. MERLIN is a network of six radio telescopes
spread out across England and operated as a national facility by the
University of Manchester's Jodrell Bank observatory. MERLIN's resolution is
the same as that of the Hubble Space Telescope but at a completely different
wavelength -- the two make perfect astronomical partners. The Hubble,
orbiting above the atmosphere, took a detailed picture of the object and
this revealed the spectacular bulls-eye. This is only one of over 20 galaxy
lenses now known.
In an ironic twist, counting the number of gravitational lenses in the sky,
including the rare Einstein rings, is the best way of seeing whether
Einstein really made his ``greatest blunder''. When he applied his General
Theory of Relativity to the Universe as it was known 80 years ago, Einstein
had to invent a repulsive force which overcomes gravity at very large
distances. This new force was soon dismissed by other astronomers but many
modern cosmologists now think that Einstein may have been right first time --
the lens searches will soon tell us where the truth lies.
Background information on gravitational lenses is available by clicking
HERE. [http://www.jb.man.ac.uk/merlin/press/PR9801/press2.html]
The results of this work will be published in Letters section of the April 1
Issue of the Monthly Notices of the Royal Astronomical Society.
L.J. King et al. ``A complete infrared Einstein ring in the
gravitational lens sytem B1938+666''
The MERLIN radio array is a UK National Facility operated by the University
of Manchester on behalf of the Particle Physics and Astronomy Research
Council. The Very Large Array is a US National Facility operated by the
National Radio Astronomy Observatory on behalf of Associcated Universities
Inc.
The astronomers involved work at the following institutes: University of
Manchester; University of Oxford; California Institute of Technology
(Pasadena); Netherlands Foundation for Radio Astronomy; University of
Groningen; Institut d'Astrophysique de Paris.
For further information contact any of the following team members:
The following may be contacted at Jodrell Bank, at
Telephone: 01477 571321
FAX: 01477 571618
Address: Nuffield Radio Astronomy Laboratories
Jodrell Bank
Macclesfield
Cheshire SK11 9DL
* Dr. Neal Jackson, Lecturer, Dept. of Physics and Astronomy, Univ.
Manchester
Email: njj@jb.man.ac.uk
* Dr. Peter Wilkinson, Acting Director, MERLIN/VLBI National Facility
Email: pnw@jb.man.ac.uk
NOTE: During the period Tuesday 31 March to Friday 3 April Dr.
Wilkinson will be attending the UK National Astronomy Meeting (NAM) at
the University of St. Andrews.
He can be contacted at via the NAM press room, whose hours are:
Tuesday to Thursday, 8.30 - 18.00, and 9.00 - 12.00 Friday.
Telephone: 01334-462168 and 462169
FAX: 01334-463130
PHOTO CAPTION:
Figure 1 [http://www.jb.man.ac.uk/merlin/press/PR9801/picture1.html]
Hubble and MERLIN image of 1938+666. A postscript version is available
for Figure 1.
(Upper) The Hubble Space Telescope picture of the distant galaxy 1938+666
which has been imaged into an Einstein ring by an intervening galaxy. The
intervening galaxy shows up as the bright spot in the centre of the ring.
The picture was taken in the infra-red region of the spectrum and the
computer-generated colour of the image has been chosen simply for ease of
viewing.
(Lower) The MERLIN radio picture of the radio source 1938+666 embedded in
the distant galaxy. The incomplete ring (or arc) shows that the radio source
is not perfectly aligned with the lens galaxy and the Earth. The lens galaxy
does not contain a radio source and hence does not show up in this picture.
The colours are computer-generated and represent different levels of radio
brightness.
Figure 2 [http://www.jb.man.ac.uk/merlin/press/PR9801/picture2.html]
Diagram demonstrating the principle of a gravitational lens. A postscript
version is available for Figure 2.
Diagram showing the formation of a gravitational lens images. In the upper
diagram the distant object, the lens galaxy and the Earth are perfectly
aligned. The lens galaxy formed a perfect ring-like image known as an
Einstein Ring. In the lower diagram the distant object, the lens galaxy and
the Earth are not perfectly aligned. In this case the lens galaxy forms
multiple images of the distant object.
*****
PRESS RELEASE: PR9801 12th March 1998
A Bull's Eye for MERLIN and the Hubble
Background Information
The observations
Because of the blurring effect of the atmosphere on optical telescopes, the
astronomers use high resolution radio telescopes -- the Very Large Array in
New Mexico and the MERLIN array in the UK (see the main MERLIN WWW page at
http://www.jb.man.ac.uk/merlin/) -- to pick out gravitational lens systems.
Only about one in every five hundred distant radio sources (galaxies and
quasars) is lensed and so thousands of radio sources have to be searched to
have a good chance of success. The British team, working together with an
international team of colleagues, have now found thirteen such systems --
more than doubling the number previously known.
The radio picture produced by MERLIN (Figure 1), which allowed the system to
be recognised in the first place, shows only part of a ring. The reason is
that, while the source of radio emission is embedded in the distant galaxy,
it is not exactly aligned with the lens galaxy. The ``optical'' picture
produced by the Hubble (Figure 1) is actually in the infra-red region of the
spectrum taken with the NICMOS camera. The wavelength used is about twice
that of red light. The infra-red emission from the distant galaxy is more
extended than the radio emission. Some of it comes from directly behind the
lens galaxy and hence a complete ring is formed.
Gravitational Lensing
Unlike the lenses with which we are familiar, in spectacles for example, a
gravitational lens can produce not one but several images of a given object;
these images may be highly distorted and magnified. Whereas a conventional
glass or plastic lens has a simply curved shape the analogy with a
gravitational lens is a piece of glass shaped like the base and stem of a
wine glass with the bowl cut off. Even without breaking the glass the ring
effect can easily be seen by tipping the glass and looking at a mark on a
piece of paper (or a table cloth) through the base.
The way in which a gravitional lens produces multiple images, including the
special Einstein ring case, is illustrated in the explanatory diagram
(Figure 2).
Why study gravitational lenses?
By studying this and other gravitational lenses astronomers can not only
measure the masses and shapes of distant galaxies, including any ``dark''
matter which will not show up in the optical or radio pictures, but also can
measure Hubble's constant which is related to the time elapsed since the Big
Bang.
Einstein's ``greatest blunder'' refers to the elusive Cosmological Constant.
This describes the strength of the long-range repulsive force he introduced
into the General Relativity equations in 1916. Other astronomers soon
showed, however, that this force was not needed to explain the properties of
the Universe as it was then known. Einstein ruefully wrote ``away with the
cosmological term''. But like a genie, once released it has proved hard to
put away and many astronomers now invoke the Cosmological Constant to
account for modern observations of the distant universe.
A Universe in which the Cosmological Constant is not identically zero has
different geometrical properties to one governed solely by gravity. Counting
gravitational lenses, in other words counting the number of lines-of-sight
``blocked'' by intervening galaxies, is acknowledged to be the best way of
measuring the geometry of the Universe at large distances. By the end of
this year we expect to be able to place the best limit so far on the
Cosmological Constant.
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=SANA=
Дата: 01 апреля 1998 (1998-04-01)
От: Alexander Bondugin
Тема: A New View Of Mass Ejections: Watching The Sun Cough
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Royal Astronomical Society Press Notices
Date: 27 March 1998
Ref. PN 98/08 (NAM5)
Issued by:
Dr Jacqueline Mitton
RAS Public Relations Officer
Phone: Cambridge ((0)1223) 564914
FAX: Cambridge ((0)1223) 572892
E-mail: jmitton@ast.cam.ac.uk
and
Peter Bond
Space Science Advisor
Phone: (0)1483-268672
Fax: (0)1483-274047
E-mail: 100604.1111@compuserve.com
A NEW VIEW OF MASS EJECTIONS: WATCHING THE SUN COUGH
It seems that the behaviour of the Sun in some ways resembles that of humans
with a dry throat: the first spasm leads to a further series of coughs in a
kind of chain reaction. In the case of the Sun, huge clouds of hot gas are
ejected during each spasm in the form of Coronal Mass Ejections. This, and
other new results from the LASCO (Large Angle Spectrometric Coronagraph)
instrument on board the European Space Agency/NASA spacecraft SOHO (Solar
and Heliospheric Observatory), will be presented at the UK National
Astronomy Meeting at the University of St Andrews by Dr Mark Lyons from the
University of Birmingham.
What Are CMEs?
Astronomers have known since the early 1970s that Coronal Mass Ejections
(CMEs) are regularly thrown out into space by the Sun. These huge clouds of
gas consist of electrically charged particles (protons and electrons) and
have a typical mass of hundreds of millions of tonnes. In some cases they
are directed towards the Earth and they travel so rapidly that they usually
cross the 150 million km gap within three days of their launch from the Sun.
Scientists would very much like to be able to forecast these events since,
on arrival, they interact with the Earth's magnetic field, producing
geomagnetic disturbances which can disrupt electricity supplies and cause
damage to satellites.
In addition, understanding how CMEs are produced is crucial to understanding
the overall workings of the Sun. They are a dominant feature of the solar
corona (the white halo seen around the Sun during solar eclipses) and may
play a major role in the behaviour of the solar magnetic field.
LASCO
The latest tool being used to advance the research into CMEs is the LASCO
instrument carried on board the SOHO satellite. LASCO is a joint project
between the University of Birmingham, the Naval Research Laboratory
(Washington DC), the Max-Planck-Institut fur Aeronomie (Germany) and the
Laboratoire d'Astronomie Spatiale (France). It consists of three telescopes
(known as coronagraphs) which are capable of blocking out the bright disk of
the Sun and allowing the fainter light from the corona to be observed.
Combined, the three coronagraphs of LASCO give images of the solar corona
from 1.1 to 30 solar radii (from just above the visible surface to a
distance of about 20 million km from the Sun). This wide angle view and its
high sensitivity give LASCO a tremendous advantage over previous
instruments.
In general, a CME is thought to occur when closed magnetic configurations in
the solar corona are destabilised by some trigger. This destabilisation then
leads to the expulsion of matter from the solar atmosphere. The latest
research at Birmingham is revealing that the entire Sun can be affected by
CMEs. This is displayed most strikingly by events observed by LASCO where an
initial mass ejection is closely followed by a series of others. In some
cases CMEs occur at widely separated points almost simultaneously. For the
first time LASCO is showing us that the corona behaves as a single unit,
capable of storing large amounts of magnetic energy which can be released
from more than one point by some initial triggering mechanism.
Further evidence for a global reaction of the corona was provided by an
event observed on the 23rd February 1997. LASCO C1 images (covering a region
from 1.1 to 3 solar radii) showed the expansion of a CME in the lower corona
moving with a speed of 880 km/s from the north-east limb of the Sun. This
quickly destabilised a sequence of much larger magnetic loop structures to
the south which then became the dominant feature of the CME. This sequence
of events implies that a higher magnetic loop system spans the solar equator
to physically connect regions in opposite hemispheres.
The Solar Wind
For a long time the Sun has been known to produce a 'wind' of charged
particles. Mass ejections from the Sun are known to contribute a significant
fraction of the total material of solar wind. LASCO observations are now
providing new information about the flow of the solar wind nearer to solar
surface where its properties have not been closely studied.
A study of CME events carried out by Professor George Simnett at Birmingham
University has shown that they begin to undergo an acceleration at a
distance of about 6 solar radii. So the LASCO observations indicate that
this is probably where the solar wind begins.
Notes for Editors
The SOHO satellite was launched in December 1995. It orbits a stable point
(the Lagrangian L1 point), situated approximately 1.5 million km from Earth
towards the Sun at which the gravitational pull on the satellite from the
Earth and the Sun are equal. This position ensures that LASCO has an
uninterrupted view of the Sun.
LASCO observations will continue as solar activity moves towards a maximum
in its 11 year cycle by the end of the century. Dr Mark Lyons is a research
fellow working on the LASCO project at the University of Birmingham. The
solar group at the University of Birmingham, headed by Prof. George Simnett,
is using images from LASCO to provide new insights into the CME process.
More information about the LASCO research carried out by the solar group at
the University of Birmingham and about the SOHO project, including images of
CMEs, can be found on the following Web sites.
* http://www/research/solar.html
* http://lasco-www.nrl.navy.mil/lasco.html
Contact
Dr Mark Lyons,
School of Physics and Astronomy,
University of Birmingham, Birmingham B15 2TT.
Tel: +44 (0)121 414-4608
E-mail: mal@star.sr.bham.ac.uk
Press room at the National Astronomy Meeting, University of St Andrews
(8.30 - 18.00 Tue 31 March to Thur 2 April; 9.00 - 12.00 Fri 3 April):
Phone: 01334-462168 and 01334-462169
Fax: 01334-463130
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=SANA=
Дата: 01 апреля 1998 (1998-04-01)
От: Alexander Bondugin
Тема: Hubble Images Of Comet Hyakutake Released
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The University of Michigan
News and Information Services
412 Maynard
Ann Arbor, Michigan 48109-1399
Contact: Adam Marcus
Phone: (734) 647-7046
E-mail: marcusa@umich.edu
News Release: March 27, 1998
Hubble pictures from study of Comet Hyakutake released
EDITORS: A complete description of the results of the program and
the individual images can be accessed via the World Wide Web from
URL http://www.sprl.umich.edu/SPRL/Comets/Hyakutake.html
ANN ARBOR -- University of Michigan astronomer Michael Combi has
released two images of the inner coma, or gassy head, of Comet
Hyakutake, which passed within about 16 million kilometers of Earth
in 1996. The computer-generated pictures were taken with NASA's
Hubble Space Telescope on April 4, 1996, during observations led by
Combi, a research scientist at the U-M College of Engineering.
These images, made using Hubble's Wide Field Planetary Camera 2,
were part of a study of water photochemistry in comets. Hydrogen
atoms are the most abundant gas in the entire coma of the comet.
They are produced when solar ultraviolet light divides molecules of
water, the major constituent of the nucleus of the comet. Using
Hubble's High Resolution Spectrograph, Combi and his colleagues
were able to determine that Hyakutake was churning out between 7
and 8 tons of water per second, by matching a computer model of the
comet the researchers had created earlier to the observations.
"The importance of such a detailed model is that it permits the
accurate calculation of the production rate of water from
observations," Combi said. The results appear in an article in the
Feb. 20, 1998, issue of the Astrophysical Journal (vol 494, pages
816-821).
The first image, shown in red, was taken through a narrow-band red
filter that shows only sunlight scattered by dust particles in the
inner coma of the comet. The second, shown in blue, was taken with
an ultraviolet "Woods" filter image that shows the distribution of
scattered ultraviolet radiation from hydrogen atoms in the inner
coma.
The inner yellow region near the center of the red dust image is
dominated by the contribution from the dust which shows sunward
directed spiral jets toward the upper right, and the thin straight
particle trail pointing toward the lower left. The trail was a
permanent feature of the comet around the time of its close
approach to the earth in late March and early April. Also barely
visible just beyond the lower left end of the trail are two of the
many condensations which were seen to travel slowly down the tail
are believed to be clumps of material released from the comet's
nucleus -- a 2-3 km chunk of dirty ice.
The inner white region of the blue image appears to show that the
hydrogen atoms like the dust might be preferentially ejected toward
the sunward or day side of the nucleus. However, this is not true.
The asymmetric ultraviolet radiation pattern is produced by a
roughly spherical distribution of hydrogen atoms because they are
so efficient at scattering the incoming solar ultraviolet light.
The atoms on the sunward side actually shadow the atoms on the
tailward or night side of the coma. The same detailed model
analysis of the coma which explains the expansion of the hydrogen
atoms in the coma also explains the appearance of the image.
Combi's team included Michael Brown of the California Institute of
Technology, Paul Feldman of the Johns Hopkins University, H. Uwe
Keller of the Max Planck Institute, Lindau, Robert Meier of the
Naval Research Laboratory, and William Smyth of Atmospheric and
Environmental Research, Inc.
[NOTE: Images supporting this release can be accessed directly at
http://www-personal.engin.umich.edu/~mcombi/HST/hyaku.html]
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=SANA=
Дата: 01 апреля 1998 (1998-04-01)
От: Alexander Bondugin
Тема: Hunt Is On For More Extrasolar Planets
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Royal Astronomical Society Press Notices
Date: 30th March 1998
For immediate release
Ref. PN 98/11 (NAM8)
Issued by:
Dr Jacqueline Mitton
RAS Public Relations Officer
Phone: Cambridge ((0)1223) 564914
FAX: Cambridge ((0)1223) 572892
E-mail: jmitton@ast.cam.ac.uk
HUNT IS ON FOR MORE EXTRASOLAR PLANETS
The UK National Astronomy Meeting (NAM) at the University of St Andrews
opens on Tuesday 31st March with astronomers expressing high hopes of
finding more extrasolar planets in the near future, and of learning much
more about planetary systems beyond our own, as major new research projects
get under way at the Anglo-Australian Observatory (AAO) in New South Wales,
and at the observatory on La Palma in the Canary Islands.
The Anglo-Australian Planet Search Project
Commenting on the AAO programme, AAO astronomer Chris Tinney said, "This
southern hemisphere program is exciting, because it is the first time the
virgin territory of the southern sky has been searched. Every southern star
we observe is being checked for the first time. And the experience of the
northern hemisphere shows we can expect to find the first new planets within
about a year. Altogether, we hope to double the number of nearby stars with
known planets over the next five years."
The AAO observations form part of an international project to examine nearby
stars similar to the Sun for the presence of planets. The project stems from
the highly successful search by Geoffrey Marcy and Paul Butler at Lick
Observatory in California. Marcy and Butler are the world's leading
discoverers of extrasolar planets with 6 independent finds to their credit.
Because many stars in the far southern sky are not visible from Lick, Paul
Butler will be working on the 3.9-metre Anglo-Australian Telescope at the
AAO in collaboration with Chris Tinney, Hugh Jones (Liverpool John Moores
University) and Alan Penny (Rutherford Appleton Laboratory), who will talk
about the project at the NAM.
The LA Palma Exoplanet Programme
Observations to start in May on La Palma will be described by Professor
Keith Horne of the University of St Andrews, who is a member of a 20-strong
team of astronomers from 15 different institutions, mainly in Europe. He
explains, "We were awarded the 1998 'International Time Project' at La Palma
and we have about 5% of the 1998 telescope time on all of the La Palma
telescopes." Professor Horne is involved with searching for extrasolar
planets by two different techniques -- looking for any that act as
gravitational lenses, and looking for evidence that a planet is passing in
front of its parent star as it travels in orbit.
Other members of the La Palma consortium will observe stars with known
planets, where there is a very large planet orbiting close to the star. They
will be looking for signs of gas boiling off a giant planet similar to
Jupiter. A third study is concerned with disks of dust around stars where
planetary systems may still be forming. The researchers will investigate the
presence of comet-like objects which have already been discovered in the
disk around the star Beta Pictoris.
Making Sense of Extrasolar Planets
Dr William Cochran of the University of Texas, co-discoverer of the planet
orbiting the star 16 Cygni B, opens the NAM on Tuesday 31st March with an
invited talk in which he takes a long hard look at the facts on extrasolar
planets as they stand today, about a year since the last discovery was
announced. He will look at whether any of the 'planets' may really be brown
dwarfs (failed stars) and whether it is possible to tell the difference.
Dr Cochran says, "The question of whether these objects are planets or brown
dwarfs is much more than an issue of semantics. I define a brown dwarf as a
sub-stellar object formed in the same manner as a star. On the other hand, a
planet is an object formed in the way we believe the planets in our solar
system formed, by accretion in a circumstellar disk. Very different physical
processes were involved. So there is no reason to believe that there should
be a nice clean boundary between the masses of planets and brown dwarfs. The
mass ranges of the two kinds of object may overlap, or there may be a 'mass
gap' between planets and brown dwarfs. Those of us who have discovered the
low mass objects have labelled them as planets, but mostly through wishful
thinking. For example, the companion to 70 Virginis is commonly called a
"planet", while the virtually identical object in orbit around the star
HD114762 was called a "brown dwarf" by its discoverer. I believe that two
different physical processes are indeed at work in the formation of these
objects, and that the dividing line is somewhere around 10 Jupiter masses.
The companions to 70 Virginis and HD114762 could well be either planets or
brown dwarfs, but the lower mass companions are most likely true planets."
Further Information on the Internet
Further information on these topics can be found at the following WWW sites:
Anglo-Australian Telescope Planet Search Programme:
http://www.aao.gov.au/local/www/cgt/planet/aat.html
G. Marcy and P. Butler's programme at Lick Observatory:
http://cannon.sfse.edu/~williams/planetsearch/news.html
Contact Information for the National Astronomy Meeting, University of St
Andrews:
Press room (open 8.30 - 18.00 Tue 31 March to Thur 2 April; 9.00 -
12.00 Fri 3 April):
Phone: 01334-462168 and 01334-462169; Fax: 01334-463130
Contacts
(usual phone nos etc.)
Dr Alan Penny
Rutherford Appleton Laboratory
Didcot, Oxfordshire OX11 0QX, UK
E-mail: alan.penny@rl.ac.uk
Phone +44 (0)1235 445675
Fax: +44 (0)1235 446667
Dr Chris Tinney
Anglo-Australian Observatory
E-mail: cgt.@aaoepp.aao.gov.au
Phone: +61 2 9372 4849
Professor Keith Horne
University of St Andrews
E-mail: kdh1@st-andrews.ac.uk
Phone: +44 (0)1334 463322
Dr William Cochran
McDonald Observatory
The University of Texas at Austin
Austin, TX 78712-1083 USA
E-mail: wdc@shiraz.as.utexas.edu
Phone: +1 512-471-6474
Fax: +1 512-471-6016
Hа сегодня все, пока!
=SANA=
Дата: 01 апреля 1998 (1998-04-01)
От: Alexander Bondugin
Тема: Magnetism The Key To Mysteries Of The Sun
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Royal Astronomical Society Press Notices
Date: 27 March 1998
Ref. PN 98/10 (NAM 7)
Issued by:
Dr Jacqueline Mitton
RAS Public Relations Officer
Phone: Cambridge ((0)1223) 564914
FAX: Cambridge ((0)1223) 572892
E-mail: jmitton@ast.cam.ac.uk
MAGNETISM THE KEY TO MYSTERIES OF THE SUN
Solar physicists at the University of St Andrews are combining theory with
results from the European Space Agency/NASA Solar and Heliospheric
Observatory (SOHO) to solve a long-standing mystery about the Sun -- why is
the solar corona so hot? According to Professor Eric Priest and his
colleagues, energy from the Sun's magnetic surface is channelled into the
corona by a process called 'magnetic reconnection'. In the corona, the
magnetic field is broken down, releasing heat and raising the temperature of
the gas to millions of degrees. And using SOHO observations they have also
been able to show that there is little evidence so far to support a
competing theory.
This new work will be included by Professor Priest in his talk, 'A startling
new Sun', at the National Astronomy Meeting at the University of St Andrews
on Wednesday 1st April.
The surface of the Sun has a temperature of only 6000 degrees kelvin (5730
degrees C), but its outermost layers of tenuous gas -- the corona, which is
visible at a total solar eclipse -- is surprisingly very much hotter. Its
temperature is several million degrees. How the corona is heated represents
one of the most important unsolved mysteries in astrophysics which has
tantalized solar physicists for the past 40 years.
"But the coronal heating problem is a really tough and complex one to
tackle" says Professor Priest. "The corona consists of several types of
structure which may be heated by different mechanisms. There are huge
magnetic loops arching high above the solar surface, tiny intense cores of
emission called X-ray bright points, and dark regions, called coronal holes,
where the nature of the magnetic field allows hot gas (plasma) to stream out
into interplanetary space."
Two main theories have been proposed to explain the high temperature of the
solar corona. One of them involves magnetic waves travelling upwards from
the surface of the Sun. Like water waves, magnetic waves carry energy. The
other, the 'magnetic reconnection' theory, involves the generation of
intense electric currents to discharge the energy directly into the corona.
To test the wave theory, Dr Robert Walsh and Dr Jack Ireland at St Andrews
used the Coronal Diagnostic Spectrometer (CDS) instrument on SOHO to search
for magnetic waves with periods between 30 and 1000 seconds in an active
region of the Sun's surface where the magnetic field is strong. The magnetic
structure of the region was also mapped out using data from the Michelson
Doppler Imager (MDI) instrument, also on SOHO. The results were startling:
in the layers of gas nearest the visible surface of the Sun (the
chromosphere), where the temperature is about 10,000 degrees kelvin, there
are clear wave-like motions with periods of about 300 seconds and 600
seconds; further up (the transition region) where the temperature is 200,000
degrees kelvin the waves can also be seen. But by the time the one-
million-degree corona is reached no such wave motions were detected. It
appears that waves are travelling up some distance, but they are not getting
far enough to heat the corona.
However, the St Andrews team discovered that intense coronal brightenings
known as X-ray bright points are heated by magnetic reconnection.
Observations from a rocket instrument called NIXT have shown that such
bright points have a complex internal structure of interacting magnetic
loops. This structure agrees very well with predictions made by Professor
Priest, Dr Clare Parnell and Dr Sara Martin.
"Magnetic reconnection gives a unified explanation for many diverse
observations from SOHO that all fall into place when viewed together" says
Professor Priest. For example:
* Recently, Karel Schrijver, Alan Title and colleagues at Lockheed
Martin discovered from MDI observations that the solar surface
consists of a "magnetic carpet", in which the magnetic structure is
completely replenished every 40 hours. The mechanism for changing
the magnetic connections so rapidly is the magnetic reconnection
process.
* With the SUMER instrument, rapid jets of plasma in explosive events
have been discovered and these are also naturally produced by magnetic
reconnection.
* The discovery made with the CDS instrument of bright spots that have
been called "blinkers" are an inevitable consequence of magnetic
reconnection.
Said Professor Priest, "It is only now that we are beginning to analyse and
digest the results from SOHO, but there are some amazing surprises that are
revolutionising our understanding of the Sun -- our closest star".
Images to support this story can be found at:
* http://www-solar.dcs.st-andrews.ac.uk/~robert/press.html
The general SOHO Web site is at:
* http://sohowww.nascom.nasa.gov/
Note
The SOHO satellite was launched 2 years ago as a major joint project between
the European Space Agency (ESA) and NASA, with ESA as the major partner.
Contacts
All at the University of St Andrews
Fax: 01334 463748
Prof. Eric Priest
Phone: 01334-463709 or 01334-474975
E-mail: eric@dcs.st-and.ac.uk
Dr Jack Ireland
Phone: 01334-463750
E-mail: jack@dcs.st-and.ac.uk
Dr Clare Parnell
Phone: 01334-463706
E-mail: clare@dcs.st-and.ac.uk
Dr Robert Walsh
Phone: 01334-463711
E-mail: robert@dcs.st-andrews.ac.uk
Press room at the National Astronomy Meeting, University of St Andrews
(8.30 - 18.00 Tue 31 March to Thur 2 April; 9.00 - 12.00 Fri 3 April):
Phone: 01334-462168 and 01334-462169
Fax: 01334-463130
Hа сегодня все, пока!
=SANA=
Дата: 01 апреля 1998 (1998-04-01)
От: Alexander Bondugin
Тема: Milky Way May Be Smaller Than We Thought
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Royal Astronomical Society Press Notices
Date: 27 March 1998
Ref. PN 98/06 (NAM 3)
Issued by:
Dr Jacqueline Mitton
RAS Public Relations Officer
Phone: Cambridge ((0)1223) 564914
FAX: Cambridge ((0)1223) 572892
E-mail: jmitton@ast.cam.ac.uk
MILKY WAY GALAXY MAY BE SMALLER THAN WE THOUGHT
In a new study, astronomers Dr Michael Merrifield and Dr Robert Olling of
the University of Southampton have come up with revised estimates for the
size of our galaxy, the Milky Way, and for the rate at which it is turning.
They have found that the Milky Way is significantly smaller, and is spinning
more slowly, than has previously been assumed. These results are being
presented by Dr Merrifield on Thursday 2nd April at the UK National
Astronomy Meeting at the University of St Andrews.
Astronomers have known for almost a century that the solar system is located
toward the outskirts the Milky Way, and that it follows a roughly circular
path around the galactic centre. However, the quantitative details of this
picture -- how far we are from the centre of the Galaxy and how fast we are
travelling on our orbit -- have proved hard to pin down. For example, recent
estimates of the distance to the galactic centre have ranged from 21,000
light years up to 30,000 light years, with a "best" estimate of around
28,000 light years.
These uncertainties are particularly troubling to astronomers trying to
understand the motions of stars in the Milky Way. The way stars move through
space is largely controlled by the gravitational pull of our Galaxy as a
whole, and the strength of that pull can only be estimated when astronomers
know the size of our galaxy, and how rapidly the Sun is orbiting around its
centre.
Michael Merrifield and Robert Olling have shown how this problem can be
turned on its head. They have looked at several studies of the actual
observed motions of stars in the Milky Way. They say that the motion of the
stars can only be understood if the Sun is located some 23,000 light years
from the centre of the Milky Way, travelling at approximately 185 kilometres
per second. Although within the range of existing estimates, these new
results suggest that the values usually quoted for our distance from the
galactic centre (28,000 light years) and the Sun's speed of rotation in its
galactic orbit (220 kilometres per second) are significantly too high.
A lower value for the size of our galaxy has repercussions on a much larger
scale: the size of other objects in the Universe are often measured relative
to the size of the Milky Way. Thus, if astronomers have previously
overestimated the size of our galaxy, they will also have overestimated the
sizes of other objects, and, indeed, of the Universe as a whole. It is
therefore quite possible that the Universe is some 15% smaller than has been
previously believed.
Contact
Dr Michael Merrifield
Department of Physics and Astronomy
University of Southampton
Highfield
Southampton
SO17 1BJ
Phone no: 01703 592092
Fax no: 01703 593910
E-mail: mm@astro.soton.ac.uk
Note: Dr Merrifield will be at the National Astronomy Meeting, 31 March to 2
April.
Press room at the National Astronomy Meeting, University of St Andrews
(8.30 - 18.00 Tue 31 March to Thur 2 April; 9.00 - 12.00 Fri 3 April):
Phone: 01334-462168 and 01334-462169
Fax: 01334-463130
Hа сегодня все, пока!
=SANA=
Дата: 01 апреля 1998 (1998-04-01)
От: Alexander Bondugin
Тема: Oxford Scientists Uncover Strange Workings Of Jupiter's Great Red Spot
Subject: Oxford Scientists Uncover Strange Workings Of Jupiter's Great Red Spot
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Royal Astronomical Society Press Notices
Date: 27 March 1998
Ref. PN 98/12 (NAM9)
Issued by:
Dr Jacqueline Mitton
RAS Public Relations Officer
Phone: Cambridge ((0)1223) 564914
FAX: Cambridge ((0)1223) 572892
E-mail: jmitton@ast.cam.ac.uk
and
Peter Bond
Space Science Advisor
Phone: (0)1483-268672
Fax: (0)1483-274047
E-mail: 100604.1111@compuserve.com
OXFORD SCIENTISTS UNCOVER THE STRANGE WORKINGS OF JUPITER'S GREAT RED SPOT --
AND OTHER SECRETS OF THE JOVIAN ATMOSPHERE
For well over two years, scientists from the department of Atmospheric,
Oceanic & Planetary Physics at Oxford University have been studying weather
and cloud formations on a world more than 600 million km away -- the planet
Jupiter. The latest results of their research will be presented at the UK
National Astronomy Meeting on Tuesday 31st March by Professor Fred Taylor,
co-investigator for the NIMS instrument on the Galileo spacecraft, which is
currently orbiting Jupiter. These results include the revelation of
remarkable structure in Jupiter's Great Red Spot.
The giant planet Jupiter is famous for its colourful, swirling clouds. The
most notable feature among this ever-changing turbulence is the Great Red
Spot, a huge storm system that could swallow up three Earths and is known to
have existed for at least three centuries.
One of the instruments on board the Galileo orbiter being used to study the
Jovian atmosphere and the Great Red Spot is the Near-Infrared Mapping
Spectrometer (NIMS). The capability of NIMS to obtain spatial and spectral
information simultaneously is ideal for investigating the composition,
vertical layering, optical thickness, and fine structure of Jupiter's
mysterious cloud layers. The scientists hope that continued observations
with NIMS will help to explain a number of the following mysteries:
1) Although theories abound, it is still not known what gives rise to
the bright colorations of the Jovian clouds -- for example, the red
pigment in the Great Red Spot or the various yellows and browns.
2) The nature of the circulation which gives rise to the east-west,
belt-zone cloud structure is controversial.
3) What creates and sustains the various giant weather systems (of
which the Great Red Spot is just one example of a whole family of
different types of giant eddies).
The analysis of the data is still at a relatively early stage, but several
preliminary results will be presented at NAM.
Winds, Storms and the Great Red Spot
Jupiter has high winds, and a large number of very large, very long-lived
storm systems can be seen on the planet at any one time. The most famous of
these is the Great Red Spot (GRS), which is revealed as having a most
remarkable structure in the new data. Most astronomers believed it was a
deep mass of cloud. Instead, it has a spiral arm structure of clouds, with
gaps between which enable NIMS to see through the GRS into the deep,
relatively clear atmosphere below. Futhermore, the cloud structure is higher
in the centre by more than 10 km and tilted towards one side, something like
a crooked spiral staircase. What seems to be happening is that wet air from
the deep atmosphere is rising rapidly in a relatively narrow region in the
centre of the GRS, and then spraying out above the tops of the ammonia
clouds while rotating, rather like a giant garden sprinkler. In some ways
this is similar to what happens in a terrestrial hurricane, but the Jovian
storm is much bigger than the entire Earth.
The Nature of Jupiter's Cloud Layers
As expected, the main cloud layer on Jupiter is made up of frozen ammonia
crystals, and lies at a pressure level of around half a bar (1 bar is the
mean pressure at the surface of the Earth). Although anticipated to resemble
terrestrial cirrus clouds, the Jovian, ammonia-ice version is made of
particles around a hundred times smaller than those in water-ice clouds on
Earth.
The ammonia clouds are overlain by a thick haze at much higher levels in
Jupiter's atmosphere. This appears to be a photochemical smog made up of
liquid hydrocarbon droplets. A similar layer blankets Saturn's moon Titan
and prevents us from seeing Titan's surface. Although thinner than Titan's,
the Jovian haze is unexpectedly substantial, and varies with time and place
across the planet.
There is a thicker cloud layer below both the haze and the ammonia cloud.
This may be the theoretically-predicted hydrogen sulphide (as NH4SH) cloud
at around the one-and-a-half bar level (one and a half times the sea level
air pressure on Earth), or a combination of that and an even deeper water
cloud. New data is being acquired to try to resolve this point.
The Composition of Jupiter's Atmosphere
Jupiter's atmosphere is mainly hydrogen, with about 15% helium and a number
of minor constituents, the most important of which are measured and mapped
by NIMS. Weather on Earth centres around the condensation and evaporation of
water. On Jupiter three species, ammonia, phosphine, and water vapour, can
condense, making for a remarkably complicated climate. The new data have
shown that water, in particular, is very variable. This helps explain the
very low water abundance measured by the Galileo probe when it plunged into
Jupiters clouds in December 1995. It happened, by chance, to enter a
particularly dry region.
Notes
The Oxford researchers are part of an international science team for the
Near Infrared Mapping Spectrometer on the Galileo orbiter (Principal
Investigator is Dr. Robert W. Carlson of the Jet Propulsion Laboratory in
Pasadena, California).
Galileo is a $1.5 billion NASA mission to explore the Jupiter system at
close quarters over a long period. The orbiter has been returning data on
the planet and its four largest moons since 7 December, 1995. A probe was
also released into Jupiter's atmosphere which returned unique information on
the structure and composition of the planets cloud layers. Although the
primary mission is now over, the orbiter and the NIMS experiment are in good
health and an extended mission is under way. This is focusing on detailed
studies of the icy satellite Europa, which is thought to have a sub-surface
ocean.
Images
NIMS images showing full hemisphere views of Jupiter are available on the
Web site at:
* http://www.atm.ox.ac.uk/user/irwin/
Contact
Professor Fred W. Taylor,
Head of Atmospheric, Oceanic and Planetary Physics,
University of Oxford.
Telephone: +44 (1865) 272903 Fax: +44 (1865) 272924
E-mail: F.Taylor@physics.oxford.ac.uk
Press room at the National Astronomy Meeting, University of St Andrews
(8.30 - 18.00 Tue 31 March to Thur 2 April; 9.00 - 12.00 Fri 3 April):
Phone: 01334-462168 and 01334-462169
Fax: 01334-463130
Hа сегодня все, пока!
=SANA=
Дата: 01 апреля 1998 (1998-04-01)
От: Alexander Bondugin
Тема: Quasar Discovered With X-Rays Is Long Ago And Far Away
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Pennsylvania State University
Contact:
Barbara K. Kennedy (814-863-4682) or Donald P. Schneider
(814-863-9554) and go to the Web at http://www.astro.psu.edu/users/dps/
3-31-98
Quasar Discovered With X-Rays Is Long Ago And Far Away
University Park, Pa. -- The most distant object ever found by
probing the universe with x-rays has been discovered by an
international team of astronomers using the x-ray satellite,
ROSAT. The object, a quasar whose 12-billion-year-old radiation
has been speeding toward Earth since the universe was in its
infancy, was detected with the deepest x-ray exposure ever made,
according to a paper to be published in the April issue of the
Astronomical Journal.
"This quasar is one of the faintest x-ray sources ever detected,"
says Donald Schneider, associate professor of astronomy and
astrophysics at Penn State and an author of the paper describing
the discovery.
Quasars, which are the most luminous objects in the universe and
are thought to contain the black-hole seeds from which all
galaxies formed, are among the most distant objects known. "A
quasar produces about 100 times as much energy as our entire
galaxy but its volume typically is less than the size of our solar
system," explains Schneider. Because radiation from quasars takes
billions of years to reach the Earth, scientists see distant
quasars as they were billions of years ago and use them as probes
to study the early history of the universe.
The researchers discovered the distant quasar, christened "RX
J105225.9+571905," by pointing ROSAT's High-Resolution Imager
(HRI) x-ray camera at a patch of sky for about a million
seconds -- a very long time by astronomers' standards -- in a study
known as the ROSAT Deep Survey. The group, including astronomers
from the United States, Germany, and Italy, obtained enough time
on the telescope to look deeper into space in x-rays than anyone
ever had done before. "The purpose of this x-ray survey was to
determine the nature of faint x-ray sources, says Guenther
Hasinger, director of the Astrophysical Institute in Potsdam,
Germany. "It surprised us by revealing one of the most distant
objects known."
In addition to Schneider and Hasinger, other astronomers involved
with this work are Maarten Schmidt at Caltech, Ingo Lehmann at
Potsdam, James Gunn at Princeton University, Riccardo Giacconi at
the European Southern Observatory, J. Tr=FCmper at the Max Plank
Institute, and Gianni Zamorani in Bologna.
The enormous energies released by a quasar result from matter
tumultuously tumbling into its central black hole during the
initial formation of a galaxy, many astronomers believe. Quasars
are observed to be plentiful early in the history of the universe
but to be quite rare today. The black holes still exist, but have
had time by now to devour all the matter within their reach.
"There is good evidence that a black hole resides at the center of
our Milky Way galaxy, but we do not see a quasar because there is
no material currently falling into the black hole," Schneider
says.
In order to gauge the distance from Earth to the objects revealed
by ROSAT's x-ray observatory, the scientists had to study them
with one of the world's largest optical telescopes, the Keck
telescope in Hawaii. "The X-ray satellite reveals that there is an
X-ray source in this part of the sky, but it doesn't tell us what
it is and it doesn't tell us how far away it is -- we determine that
from its visible light," said Hasinger. The most distant objects
are speeding away the fastest, so their visible light appears to
be more "redshifted," or skewed toward the red end of the
spectrum.
"This quasar is so faint in visible light, it is near the limit of
what the giant Keck telescope can measure and -- because there are
large numbers of optical objects at these brightnesses -- our x-ray
resolution had to be very accurate in order to determine which
object our x-ray source matches in the Keck optical image,"
Hasinger explains. The German team, led by Hasinger, developed the
techniques that made it possible for the astronomers to assign
very accurate celestial positions to x-ray sources in the ROSAT
survey. "The HRI now yields positions that are accurate to about 2
arc seconds -- less than one-one-thousandth of a degree -- whereas
before we were getting positions accurate only within 5 to 10
arc-seconds."
The researchers discovered that the new quasar is located at
redshift 4.45, which is so far away that we see it as it appeared
when the universe was only about nine percent of its current age.
"Most of the other objects in the survey turned out to be galaxies
or quasars much closer to Earth, with redshifts less than two,"
Schneider says.
While a few objects more distant than the new quasar have been
discovered, this is the most distant object ever discovered in an
x-ray survey, according to the astronomers. Neil Brandt, assistant
professor of astronomy and astrophysics at Penn State, has been
investigating the x-ray properties of distant quasars.
"Altogether, there are about 100 high-redshift quasars now known
and x-rays have been detected coming from only about 9 of them,"
Brandt says. "We suspect the others are producing x-rays that are
just too weak to be detected with our current instruments and
typical exposure times."
Astronomers may have to wait only until the end of this year to
get a next-generation x-ray camera that will produce much sharper
images than are possible now. The "AXAF Charge-coupled device
Imaging Spectrometer" (ACIS), which is scheduled for a Space
Shuttle launch this fall, is one of the instruments on the world's
most powerful X-ray-astronomy observatory, NASA's Advanced X-ray
Astrophysics Facility (AXAF). AXAF will be the third of NASA's
"Great Observatories" to be launched, following the Hubble Space
Telescope, which detects ultraviolet, visible, and infrared rays,
and the Compton Gamma-Ray Observatory, which detects gamma rays.
"Among the wonders the ACIS camera is designed to see is the early
growth of the seeds of quasars in the infant universe," says
Gordon Garmire, the Evan Pugh Professor of Astronomy and
Astrophysics at Penn State and the principal investigator who
conceived and designed the camera.
"This research holds great promise for our future work at Penn
State," Schneider comments. "With Dr. Garmire's ASIS camera and
the next generation of large optical telescopes including the new
Hobby-Eberly Telescope, in which Penn State is a major partner, we
expect to be able to discover, identify, and locate many more very
faint x-ray objects," he says. "We will be quite surprised if a
number of them are not much closer to the beginning of time than
the quasar found in our current survey."
This research was supported by the National Science Foundation,
the National Aeronautics and Space Administration (NASA), the
German Center for Space Research, and the Italian Space Agency.
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=SANA=
Дата: 01 апреля 1998 (1998-04-01)
От: Alexander Bondugin
Тема: This Week On Galileo - March 31 - April 5, 1998
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THIS WEEK ON GALILEO
March 31 - April 5, 1998
The remaining five days of this week continue to be busy for the Galileo
spacecraft, even though it has just completed a science encounter. Among
other activities, Galileo begins to process and transmit to Earth pictures
and science information gathered this past weekend as the spacecraft flew
past Jupiter and its moons. The series of flybys included flying over
Europa's surface at a distance of 1645 kilometers (1022 miles).
During the week, the spacecraft will execute two activities designed to
further understand and possibly circumvent the anomalous behavior exhibited
by the attitude control subsystem. The first of these, performed on Tuesday,
is designed to collect gyroscope data to track the degradation of the gyro's
performance. A repeat of the performance test is planned later in the orbit,
far from Jupiter's intense radiation environment, in hopes of determining
whether the degradation rate is time dependent or radiation dependent, or
possibly dependent on both. The second activity is performed on Wednesday
and will provide engineers with data they require to complete the design of
a flight software upgrade that could allow the spacecraft to operate on the
single gyroscope that is functioning correctly.
This week's processing and transmission to Earth of science information
contains two sets of pictures obtained by the spacecraft's camera of
Jupiter's fiery moon Io. The first set of pictures shows color views of Io's
north and south pole regions. The pictures will improve the color knowledge
of these regions by providing more than a factor of 3 greater resolution
than obtained during Galileo's primary mission, 3 kilometers (1.8 miles) per
picture element and 10 kilometers (6.2 miles) per picture element,
respectively. Monochrome pictures as good as 2.5 kilometers (1.5 miles) per
picture element were obtained in the primary mission, but the color in these
new images will be critical to identifying surface materials. The second set
of images provides a preliminary look at a region of Io that is planned to
be imaged at much higher resolution in October 1999. Both of these image
sets will also help scientists to refine observation plans for Io in late
1999.
Data processing and transmission to Earth is paused for a few hours on
Thursday as the spacecraft executes a flight path correction. This is the
first flight path correction since before this past weekend's flybys.
For more information on the Galileo spacecraft and its mission to Jupiter,
please visit the Galileo home page:
http://www.jpl.nasa.gov/galileo/
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=SANA=
Дата: 01 апреля 1998 (1998-04-01)
От: Alexander Bondugin
Тема: NASA Program Spawns New Safety Sofware For Pilots
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Don Nolan-Proxmire
Headquarters, Washington, DC March 31, 1998
(Phone: 202/358-1983)
John G. Watson
Jet Propulsion Laboratory, Pasadena, CA
(Phone: 818/354-5011)
RELEASE: 98-52
NASA PROGRAM SPAWNS NEW SAFETY SOFTWARE FOR PILOTS
Two new software packages enabling pilots to use laptops to
avoid hazardous terrain and find their place on maps are the
latest success stories of a NASA program bringing together
entrepreneurs and space engineers.
Pilots of small planes, for whom such tools have been largely
unavailable until now due to cost and the sheer size of bulky
hardware, may soon be able to carry onboard the personal computer
equivalent of collision-avoidance systems now used by the military
and commercial airlines.
"TerrAvoid" and "Position Integrity" combine Global
Positioning Satellite (GPS) data with high-resolution maps of the
Earth's topography. Dubbs and Severino, Inc., based in Irvine, CA,
has developed software that allows the system to be run on a
battery-powered laptop in the cockpit.
The packages, designed primarily for military sponsors and
now positioned to hit the consumer market in coming months, came
about as the result of the Technology Affiliates Program at NASA's
Jet Propulsion Laboratory's (JPL), Pasadena, CA. Intended to give
American industry assistance from NASA experts and to facilitate
business use of intellectual property developed for the space
program, the Technology Affiliates Program introduced the start-up
company of Dubbs and Severino to JPL's Dr. Nevin Bryant four years ago.
Dubbs and Severino had an idea for mapping software to help
private airplane pilots, inspired in part by the fatal crash of a
pilot friend of company president Bob Severino. The twist: the
package was to be completely software-driven, instead of requiring
expensive hardware, as was the norm up to that time.
Bryant's Cartographic Applications Group at JPL had developed
GeoTIFF, an architecture standard providing geo-location tools for
mapping applications. GeoTIFF proved to be the crucial key that
the start-up company needed to bring the idea to fruition,
allowing the firm to develop low-cost software packages.
GeoTIFF is now in the public domain, and its use for
commercial product development has evolved into an industry
standard over the last year. Through the Technology Affiliates
Program, Dubbs and Severino obtained JPL's assistance early on and
thus gained a jump-start in adapting the architecture for their
products' specific needs. "JPL gave us a demonstration and opened
up the red carpet. It was a match made in heaven," says Severino.
Merle McKenzie, manager of JPL's Commercial Technology
Program, said that Dubbs and Severino's ability to utilize
technology originally developed for NASA provides a strong example
of the many advantages of technology transfer programs. "This is
a win-win partnership through which yet another American business
gets a boost from the space program," McKenzie said.
"TerrAvoid" is a terrain avoidance system that graphically
shows pilots if they are flying dangerously close to mountains:
safe sections can be seen in green, while hazardous sections show
up in red, with those proportions changing in real time as the
pilot moves through hilly terrain. In a sense, the system "looks"
out over a plane's flight path, sweeping 360 degrees, warning the
pilot if there are any upcoming hazards. Ithe software integrates
GPS tracking data with maps on CD-ROM, and is approximately 1/20th
the cost of its nearest competitor.
"Position Integrity," which also co-registers real-time GPS
data with local maps on CD-ROM, is a moving map detailing the
exact position of the pilot. Because of the unique features of
GeoTIFF, this software can be adapted to operate with any map,
chart or photo image in the world, while comparable versions are
limited solely to either military, scientific or commercial maps.
GeoTIFF also enables the package to feature four windows at once,
a useful and unique option for pilots who need to work
simultaneously with maps, charts, photo images and sketches at
different scales and zoom levels.
Further details about JPL's technology transfer activities,
including the Technology Affiliates Program, are available online
at http://techtrans.jpl.nasa.gov/tu.html
JPL is a division of the California Institute of Technology.
-end-
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=SANA=
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