A hidden treasure in the Large Magellanic Cloud
NASA, ESA. Acknowledgement: Josh Lake |
Nearly
200,000 light-years from Earth, the Large Magellanic Cloud, a satellite galaxy
of the Milky Way, floats in space, in a long and slow dance around our galaxy.
Vast clouds of gas within it slowly collapse to form new stars. In turn, these
light up the gas clouds in a riot of colours, visible in this image from the
NASA/ESA Hubble Space Telescope. The Large Magellanic Cloud (LMC) is ablaze
with star-forming regions. From the Tarantula Nebula, the brightest stellar
nursery in our cosmic neighbourhood, to LHA 120-N 11, part of which is featured
in this Hubble image, the small and irregular galaxy is scattered with glowing
nebulae, the most noticeable sign that new stars are being born.
The LMC
is in an ideal position for astronomers to study the phenomena surrounding star
formation. It lies in a fortuitous location in the sky, far enough from the
plane of the Milky Way that it is neither outshone by too many nearby stars,
nor obscured by the dust in the Milky Way's centre. It is also close enough to
study in detail (less than a tenth of the distance of the Andromeda Galaxy, the
closest spiral galaxy), and lies almost face-on to us [1], giving us a bird's
eye view.
LHA
120-N 11 (known as N11 for short) is a particularly bright region of the LMC,
consisting of several adjacent pockets of gas and star formation. NGC 1769 (in
the centre of this image) and NGC 1763 (to the right, see heic1011) are among
the brightest parts.
In the
centre of this image, a dark finger of dust blots out much of the light. While
nebulae are mostly made of hydrogen, the simplest and most plentiful element in
the Universe, dust clouds are home to heavier and more complex elements, which
go on to form rocky planets like Earth. Much finer than household dust (it is
more like smoke), this interstellar dust consists of material expelled from
previous generations of stars as they died.
The
data in this image were identified by Josh Lake, an astronomy teacher at Pomfret
School in Connecticut, USA, in the Hubble's Hidden Treasures image processing
competition. The competition invited members of the public to dig out
unreleased scientific data from Hubble's vast archive, and to process them into
stunning images.
Josh
Lake won first prize in the competition with an image contrasting the light
from glowing hydrogen and nitrogen in N11. The image above combines the data he
identified with additional exposures taken in blue, green and near infrared
light.
Source: ESA/Hubble Information Centre
"Earlier
blooming exposes plants to a greater risk of experiencing cold snaps that can
damage blossoms and prevent fruiting," says Temple. "The Door County
(Wisconsin) cherry crop was ruined in 2012 because the trees bloomed very early
in response to record-breaking warmth only to be hit by subsequent frost."
"The
Door County cherry crop was ruined in 2012 because the trees bloomed very early
in response to record-breaking warmth only to be hit by subsequent frost."
The new
study keyed on the detailed phenological records of 32 native plant species in
Concord, Mass., kept between 1852 and 1858 by Thoreau, a pioneering naturalist
best known as the author of "Walden," as well as later records. A
second data set of flowering times for 23 species in southern Wisconsin was
compiled by Leopold, a renowned wildlife ecologist at the University of
Wisconsin and author of "A Sand County Almanac." Leopold and his
students gathered their data in Dane and Sauk Counties between 1935 and 1945.
From 1977 until she died in 2011, Aldo Leopold's daughter Nina Leopold Bradley
resumed the collection of phenological records near the Leopold Shack.
"Both
Thoreau and Leopold were part of the 19th century naturalist movement in which
individuals often kept meticulous daily journals recording the things they
observed in nature," notes Temple. "Most of those journals have been
lost over time, but Thoreau and Leopold were famous writers, and their journals
have been preserved, providing us with unparalleled historical data."
Comparing
modern observations with those gathered by Leopold shows that in 1942, when the
mean spring temperature in southern Wisconsin was 48 degrees Fahrenheit, black
cherry bloomed on May 31. In 2012, with a mean spring temperature of 54 degrees
Fahrenheit, black cherry blooms were observed as early as May 6. In 1942,
Leopold's notes show the woodland wildflower bloodroot blooming on April 12. In
2012, bloodroot was first observed blossoming March 17.
Together,
these two data sets provide a unique record of flowering trends in the eastern
United States over a 161-year period, says Temple.
"Leopold
and Thoreau had no idea their observations would help us understand responses
to human-caused climate change," says Temple. "But Leopold knew his
records might be useful in retrospect when he wrote: 'Keeping records enhances
the pleasure of the search, and the chance of finding order and meaning in
these events.'"
Source: University
of Wisconsin-Madison
Leave Your Comments!
Share What’s Going on
in your brain about the Topic. We need Your Response . Feel free to leave comments!
Posted by Unknown
on Saturday, January 19, 2013.
Filed under
Space and Time
.
You can follow any responses to this entry through the RSS 2.0