Thursday, March 15, 2018

Across The Universe - When Roses Aren t Red

When Roses Aren t Red:

Discover the cosmos!
Each day a different image or photograph of our fascinating universe is
featured, along with a brief explanation written by a professional astronomer.


2018 February 22




See Explanation. Moving the cursor over the image will bring up an annotated version. Clicking on the image will bring up the highest resolution version available.


When Roses Aren't Red

Image Credit &
Copyright:


Eric Coles and
Mel Helm



Explanation:

Not all roses are red
of course,
but they can still be very pretty.

Likewise, the beautiful
Rosette
Nebula
and other star forming regions are often shown in
astronomical images with a predominately red hue,
in part because the dominant emission in the nebula is
from hydrogen atoms.

Hydrogen's strongest optical emission line, known as H-alpha,
is in the red region of the spectrum, but the beauty of an
emission nebula need not be appreciated
in red light alone.

Other
atoms
in the nebula are also excited by energetic
starlight and produce narrow emission lines as well.

In this gorgeous view of the Rosette Nebula,
narrowband images are combined to show
emission from sulfur atoms in red, hydrogen in blue, and
oxygen in green.

In fact, the
scheme of mapping these narrow atomic
emission lines into broader colors is adopted in
many Hubble images
of stellar nurseries.

The image spans about 100 light-years in
the constellation Monoceros, at the 3,000 light-year
estimated
distance of the
Rosette
Nebula
.

To make the Rosette red, just follow
this link or
slide your cursor over the image.



Tomorrow's picture: the moon isn't blue




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(MTU) &
Jerry Bonnell (UMCP)
NASA Official: Phillip Newman
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