About 5,000 light years away, the Boomerang
Nebula is the coldest object known.
Works Cited
Thursday, March 20, 2014
Big Bang Confirmed?
Not exactly. However, as new studies have found, new ripples of cosmic microwave background may gives us more insight on the true details of the occurrences during the big bang.
Check out the articles below.
Works Cited
Check out the articles below.
Works Cited
Eta Carinae
Eta Carinae is a stellar system in the constellation Carina. It is located
about 7,500 to 8,000 light years away from Earth (so its parallax angle is
about 0.435 to 0.408 micro arc seconds since 1 parsec = 3.262 light years) with
a mass equivalent to that of about 100 solar masses. Its luminosity is known to
be about a million times brighter than the sun! It is currently one the biggest
and brightest stars in our galaxy. Astronomers who have studied its history and
its present conditions suspect it to be a major supernova candidate that could
erupt any day now.
History
In the 19th century, its apparent brightness dramatically
increased for two decades, then decreased. This period of time was known as the
“great eruption.” No one is absolutely sure on the cause of this eruption. Also
parts of the cloud of dust and gas in the two big globes that surround it today
are believed to have been released during this dramatic increase in brightness.
In 1843 it flared up and became the second brightest star in the sky, after
Sirius. It remained this way for about 20 years and then faded, leaving a cloud
of gas called the Homunculus Nebula. Eta Carinae has lost about 10% of its substance
during that event. Astronomers have called this a “supernova impostor.” After
this it returned to be quiet, for an unstable object that is.
From 1976 to 1998, astronomers observed start the South African
Astronomical Observatory. During this period of time, they saw an increase
across the J, H, K, and L bands, which are filters that allow certain infrared
light to pass. However, the reason for this increase in infrared light was
unknown at the time.
More Recently
After 1988, the brightness increased more rapidly than a linear trend in
the J and H bands. Although this would typically lead observers to believe it
is getting hotter, it’s highly unlikely that this is the cause of rapid brightness
increase. One theory is that the cloud of dust absorbs blue light, so it is safe
to say that this increase could just be the star’s actual brightness, seeing as
how the dust could merely be getting destroyed. However this expansion of the
cloud that surrounds Eta Carinae is not enough to account for the brightening.
Instead it is possibly losing its mass or rotating at a different speed.
In 2005, astronomers discovered that Eta Carinae has at least one
companion star. The more massive star, Eta Carinae A, is a blue star. The
increase in temperature was most likely due to an overall
increase in temperature of some component of the Eta Carinae system, which
includes the cloud of dust and gas that surround the massive star.
Although this star has been studied so much by several types of telescopes,
there is no theory that has explained what happened.
These changes have lead scientists to believe that the star is becoming
more unstable and may be headed towards another eruptive phase, perhaps a
second “great eruption.”
Fate
If Eta Carinae does indeed blow up into a supernova, would we be
affected? Luckily for us, since we are about 7500 light years away, the
radiation from the supernova would not be able to reach us.
These along with many others, are reason astronomers believe Eta Carinae
to be a candidate for the next supernova to occur within our galaxy. Especially
since there was a star in another galaxy that also seemed like a “supernova
impostor” but then a few year later, boom
This star is heading towards instability and eruption and when it goes
off it will create a blast so violent that its flash will briefly outshine the
entire Milky Way.
Works Cited
Wikipedia: http://en.wikipedia.org/wiki/Eta_Carinae
Thursday, February 13, 2014
Happy Valentine's Day!
In honor of
Valentine’s Day, I give you the “Heart and Soul” nebulae. They are located
6,000 light years from earth in Cassiopeia, near the Perseus spiral arm of our
galaxy. Enjoy!
Works Cited:
Wikipedia: http://en.wikipedia.org/wiki/Soul_Nebula
A Star's Age
How do we
determine the age of a star? Obviously, stars don’t have birthdays like we do,
but their spin can tell us all we need to know to determine their age.
A technique called gyrochronology is used to calculate
the age of a star. It utilizes a known age of a cluster of stars and its spin
rate to determine the age of an isolated star. To measure the spin, astronomers
look for changes in the brightness of the star, caused by dark spots, and
determining the time it takes for that spot to reappear. Once that rotation
period is known, it is used to determine its age by means of a mathematical
formula of that only depends on the period (time) and the mass (or color) of
the star.
This method was instrument in determining more precise
ages of stars.
Works Cited:
Wikipedia: http://en.wikipedia.org/wiki/Gyrochronology
Wednesday, February 12, 2014
Time - An Illusion or Not?
According to the
theory of general relativity, time can be defined as the fourth dimension in
space, “traversable in any direction.” Meaning that all time (present, past,
future) has no “sequential” or specific order and is coexisting together at
once. This has led many to believe that time is simply an illusion. Something
we have created in order to “measure the rate of change of the present.”
However, many others believe that the present is real, and thus, not an
illusion. Well, which is it?
To think that the
current present is real and that the past and future are not (seeing as how
they cannot be measured) is universally acceptable. If something is in the past,
in a sense, it’s not “tangible” any longer; and the same goes for the future.
However, the present is “tangible” and can be measured. But if the present is
real and as “time” continues, the present soon becomes the past and the future
becomes the present. Does this mean that our idea of “time” is wrong?
To this day there
is no right or wrong answer to that question. The search and study to put an
exact, real definition on “time” will continue. I found several articles and
videos that make their best attempts to explain time and how it works.
PBS aired an episode
titled “The Fabric of the Cosmos: The Illusion of time,” where Brian Greene
takes the viewers on a time-traveling adventure in order to gain a better
understanding of the true meaning of time, where past, present, and future can
all coexist at once.
This interesting
video captures the essence of how time can be thought of as an “illusion” based
on the fact that time is different for different perspectives. http://www.youtube.com/watch?v=vrqmMoI0wks
Works Cited:
Scientific American: http://www.scientificamerican.com/article/is-time-an-illusion/
Leigh Brasington: http://www.leighb.com/notime.htm
Gliese 667C and its Possibly Habitable Super-Earths
Gliese 667Cc is one of seven (one unconfirmed) exoplanets
that orbit Gliese 667C, one of the three stars in the system Gliese 667 located
in the constellation Scorpius. The triple-star system Gliese 667 is located
about 22.1 light years (or 6.97 pc) away from earth. That makes its parallax
0.143”. See below:
Of the seven planets, three have been categorized as
super-Earths. Super-earths are basically exoplanets that are larger in mass than
earth, yet smaller in mass than our gas giants, Uranus and Neptune. These
super-Earths also lie in what we call the “habitable zone,” the region where
temperatures are cool enough for water to exist in its liquid form. It is also
believed that these planets are rocky, like earth, and have low levels of heavy
elements, which is rare.
Gliese 667C is a red dwarf and is much fainter than
the sun. Its surface temperature is about 3700K. Its absolute magnitude is
11.03, while the sun’s is 4.83. Its radius is about 0.42 solar radii (or 2.92×108
m). The distance from this star to its super-Earth, Gliese 667Cc, is only about
0.125 AU. That means that at the surface of this planet, Gliese 667C has an angular
size of 1.79°. See below:
Gliese 667Cc has a
radius of about 1.76 earth radii (or 1.12×109 m). It is believed to
be tidally locked to its parents star, meaning they continuously face each
other in the same spot. This means it would have a hemisphere that is always
bright and a hemisphere that is always dark. Meaning if I lived there, I could
be a night owl throughout the day! Since it parent star is a part of a
triple-star system, it is possible for all three stars to be visible in the
daytime. Its orbital period is around 28 earth days (only one month). So
technically, if life could exist on this planet, we could celebrate our
birthday every month! Only down side to that is we’d all be very old, in Gliese
667Cc years. I’d be 264 years old!
The system Gliese
667 has a right ascension of 17h18m57s. Since we’re in February now, the right
ascension at midnight is 10h, meaning our field of visibility would span between
4h-16h; thus, we would not be able to see this system tonight at midnight.
However, next month, in March, the right ascension at midnight would be 12h,
giving us a field of visibility between 6h-18h; thus, we would be able to see
it at midnight next month. So mark your calendars!
Works Cited:
Wikipedia: http://en.wikipedia.org/wiki/Gliese_667
Science: http://science.kqed.org/quest/2013/03/22/gliese-667-cc-musing-the-possibilities-of-another-earth/
Universe Today: http://www.universetoday.com/103131/three-potentially-habitable-planets-found-orbiting-gliese-667c/
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