from ironic sans via bad astronomy.
Tuesday, February 12, 2008
i heart chocolate
ze frank cleverly sums up valentine's day....
a quick ode to valentine's day from jay grandin that leaves me... speechless...
a quick ode to valentine's day from jay grandin that leaves me... speechless...
Sunday, February 10, 2008
a quick trip to chile!
i had a nice, though exhausting, short trip to chile!
the ocean water was so cold that i didnt swim the entire 8 months i was in chile last year.... but this warm summertime sunday, we played in the waves!
it was good to see again my british sister that i met chile! ;)
i took a bus trip into the grape-vine-lined valley, to the small town of vicuna...
... where i explored the bug museum!
la serena always provides entertaining night life!
the chilean cuisine provided particularly delightful adventures this trip!
the ocean water was so cold that i didnt swim the entire 8 months i was in chile last year.... but this warm summertime sunday, we played in the waves!
it was good to see again my british sister that i met chile! ;)
i took a bus trip into the grape-vine-lined valley, to the small town of vicuna...
... where i explored the bug museum!
la serena always provides entertaining night life!
the chilean cuisine provided particularly delightful adventures this trip!
redshift and the distance to distant galaxies
this weekend i gave a public talk entitled a long time ago, in galaxies far, far away. it was great fun to prepare and present a talk with pretty pictures after giving so many technical talks lately! based on the responses i received, i thought i would share a popular segment with everyone here!
in order to talk about galaxies far, far away, you have to know how far away the galaxies are! it turns out that determining the distance to astronomical objects is not a trivial matter! for very distant galaxies, the best way to determine their distance is by looking at their spectra in order to determine their "look-back time" or their "redshift."
to do this, we point a telescope at a galaxy, collect the photons of light coming from the stars in that galaxy, and then send those photons through a complicated prism system, in order to see the galaxy's rainbow!
the different colors of the rainbow correspond to different wavelengths of light.
each galaxy has a unique rainbow fingerprint ("spectrum"), although some general properties are universal. the simple rainbow fingerprint below shows a nearby galaxy that has several lines, produced by hydrogen, in its spectrum. the existence of these lines and the relative spacing between them are well understood by physics and quantum mechanics.
since light has a finite speed that it travels (the speed of light is 300,000 km/sec or 670,000,000 mph!), it takes light from a distant galaxy some amount of time to travel through space to us! when we determine how long the light has been traveling thru space, we know how far away the galaxy was when it released the photons of light that eventually landed on our lucky telescope! this time is called the galaxy's "look-back time" and goes from very small up to 13.7 billion years (the age of the universe).
sounds simple enough, but how can we determine this??
the key piece of information is that the universe is expanding!! as the light from a galaxy innocently travels thru space for a couple billion years, space itself is expanding! as the light wave travels, space expands and the wavelength of light gets stretched out with space!
the original wavelength of a photon of light when it left the galaxy, is stretched out as it travels thru space so that it is a longer wavelength by the time it reaches us and lands on our telescope mirror. each of the lines from hydrogen are shifted to longer wavelengths!
we compare the spectrum of a distant galaxy to a very nearby one to see how far a particular line has shifted. the farther the shift, the farther away the galaxy, the earlier in the history of the universe the light was produced inside the galaxy! from the amount of shift of a line in a galaxy's spectrum, we get the galaxy's redshift which is a number between zero and something very large (greater than 100). note that what i've described is the galaxy's "cosmological redshift" (as opposed to a doppler redshift).
mathematically, the redshift, z, is equal to the ratio of the wavelength of light that we observe to the emitted wavelength of light as it was when it left the home galaxy, minus one.
a galaxy with a redshift of one (z=1), emitted the light we observe about 8 billion years ago, when the universe was about 6 billion years old!
here's an example of a real two-dimensional galaxy spectrum, showing the intensity of various lines of hydrogen in addition to oxygen and sulfur.
in order to talk about galaxies far, far away, you have to know how far away the galaxies are! it turns out that determining the distance to astronomical objects is not a trivial matter! for very distant galaxies, the best way to determine their distance is by looking at their spectra in order to determine their "look-back time" or their "redshift."
to do this, we point a telescope at a galaxy, collect the photons of light coming from the stars in that galaxy, and then send those photons through a complicated prism system, in order to see the galaxy's rainbow!
the different colors of the rainbow correspond to different wavelengths of light.
each galaxy has a unique rainbow fingerprint ("spectrum"), although some general properties are universal. the simple rainbow fingerprint below shows a nearby galaxy that has several lines, produced by hydrogen, in its spectrum. the existence of these lines and the relative spacing between them are well understood by physics and quantum mechanics.
since light has a finite speed that it travels (the speed of light is 300,000 km/sec or 670,000,000 mph!), it takes light from a distant galaxy some amount of time to travel through space to us! when we determine how long the light has been traveling thru space, we know how far away the galaxy was when it released the photons of light that eventually landed on our lucky telescope! this time is called the galaxy's "look-back time" and goes from very small up to 13.7 billion years (the age of the universe).
sounds simple enough, but how can we determine this??
the key piece of information is that the universe is expanding!! as the light from a galaxy innocently travels thru space for a couple billion years, space itself is expanding! as the light wave travels, space expands and the wavelength of light gets stretched out with space!
the original wavelength of a photon of light when it left the galaxy, is stretched out as it travels thru space so that it is a longer wavelength by the time it reaches us and lands on our telescope mirror. each of the lines from hydrogen are shifted to longer wavelengths!
we compare the spectrum of a distant galaxy to a very nearby one to see how far a particular line has shifted. the farther the shift, the farther away the galaxy, the earlier in the history of the universe the light was produced inside the galaxy! from the amount of shift of a line in a galaxy's spectrum, we get the galaxy's redshift which is a number between zero and something very large (greater than 100). note that what i've described is the galaxy's "cosmological redshift" (as opposed to a doppler redshift).
mathematically, the redshift, z, is equal to the ratio of the wavelength of light that we observe to the emitted wavelength of light as it was when it left the home galaxy, minus one.
a galaxy with a redshift of one (z=1), emitted the light we observe about 8 billion years ago, when the universe was about 6 billion years old!
here's an example of a real two-dimensional galaxy spectrum, showing the intensity of various lines of hydrogen in addition to oxygen and sulfur.
Saturday, February 9, 2008
dew bug
stunningly beautiful example of refraction, using a brilliant target!
see more of martin amm's photography: here
see more of martin amm's photography: here
Friday, February 8, 2008
carnival of space - #40
hop over to the orbiting frog blog, for the 40th installment of the carnival of space!
Thursday, February 7, 2008
upside down orion!
i'm thrilled to be under southern skies again!
in general, when i walk outside of a roofed-structure at night, i look up immediately to see what stars and planets are out, in order to get acquainted with my relative time and location... just 4 days ago, i eagerly awaited the southern summer sun to set so i could look up to see orion upside down (!) and the southern cross above my head… reminding me how far around the other side of the earth i’ve come for this job interview!
i survived my interview, but i have to say it was the most intense one i've had! wow.... i was relieved when it ended, but of course i circled all my responses over and over in my head afterwards, wondering about their "correctness." i tried to be as honest as i could be without getting bogged down with worries about what the "right" answer was they might be expecting. i think i succeeded at this point, but their detailed questions have given me interesting things to ponder for the last couple days!
i leave this evening to head back to the northern hemisphere. i'm excited to discuss the universe a long time ago, in galaxies far, far away!
in general, when i walk outside of a roofed-structure at night, i look up immediately to see what stars and planets are out, in order to get acquainted with my relative time and location... just 4 days ago, i eagerly awaited the southern summer sun to set so i could look up to see orion upside down (!) and the southern cross above my head… reminding me how far around the other side of the earth i’ve come for this job interview!
i survived my interview, but i have to say it was the most intense one i've had! wow.... i was relieved when it ended, but of course i circled all my responses over and over in my head afterwards, wondering about their "correctness." i tried to be as honest as i could be without getting bogged down with worries about what the "right" answer was they might be expecting. i think i succeeded at this point, but their detailed questions have given me interesting things to ponder for the last couple days!
i leave this evening to head back to the northern hemisphere. i'm excited to discuss the universe a long time ago, in galaxies far, far away!
Saturday, February 2, 2008
darwinian valentine's day
did anyone get up early enough to see the conjunction of venus and jupiter? i almost did, but not quite. let me know if you got any good pictures!
this afternoon, i'm leaving on a jetplane for the spanish-speaking wonderland... chile! i'm extremely excited to be heading back to my home of most of 2007!! the main purpose of the trip is for a job interview (think good thoughts for me!), but i also plan to visit old friends, drive to the mystical valley, drink some pisco sours, eat an empanada or four, hopefully listen to fantastic folk music, and lounge a bit on the beach!
i might not be able to post much while traveling, so i leave you with a challenge... enter the darwin valentine's day card contest being held by the skepchicks!!! i think this is a hilarious idea, and i'm feeling inspired to try to come up with something even half as clever as the one they share...
good luck!
this afternoon, i'm leaving on a jetplane for the spanish-speaking wonderland... chile! i'm extremely excited to be heading back to my home of most of 2007!! the main purpose of the trip is for a job interview (think good thoughts for me!), but i also plan to visit old friends, drive to the mystical valley, drink some pisco sours, eat an empanada or four, hopefully listen to fantastic folk music, and lounge a bit on the beach!
i might not be able to post much while traveling, so i leave you with a challenge... enter the darwin valentine's day card contest being held by the skepchicks!!! i think this is a hilarious idea, and i'm feeling inspired to try to come up with something even half as clever as the one they share...
good luck!
space flight: challenges always re-enter
this week we're reminded to learn from our mistakes... by not forgetting them! three major NASA-related events that have helped shape our image of space exploration, all occured in various years during this week. for a more developed summary, see professor astronomy's blog. i'll just mention the two events that i remember from personal experience.
1) on January 28, 1986, the shuttle Challenger exploded. i was young at the time, but i have a very vivid memory of the moment. my class was privileged to watch the launch live and we were all very excited! i sat on the floor, next to my best friend jessica, looking up at the TV. the image of the liftoff and the arc made by the smoke in the air is very vivid in my mind. then the line grew into an unexplainably big puff ball while white streaks shot out to the sides.
the explosion seemed surreal and confusing. my young mind's first thought was "that's odd. i don't think that was supposed to happen." it was ultimately the reaction of the teachers in the room that made me understand the seriousness of the situation. i remember deciding at that moment that i did NOT want to be an astronaut!
2) On February 1, 2003 i was in west texas observing at the mcdonald observatory. i was there for an 8-night observing run on the 2.7m telescope and became excited when i heard the shuttle columbia would pass over texas on its way to landing in florida! depending on the shuttle's final descent path, i would be able to see it crossing the sky, low to the north, early in the morning. i followed NASA's liftoff webpage all night to track columbia in its orbit, in anticipation of seeing the shuttle! while i finished up some morning calibration exposures, i stood out on the catwalk that surrounds the telescope.... looking off to the north.
NASA estimated that the shuttle would pass by between 7:30 and 8am (central time, of course), so i watched from about 7:30 until 8:15am (it was february and cold on the mountain top!). The sun had risen by 8am and since the shuttle would have crossed the sky very low on the horizon, i suspected that i would not see it at all. so i finished the night's observing a little disappointed having not seen the shuttle. i closed down the telescope, walked across the road to my dorm room and went straight to sleep.
it wasnt until i woke up around 4pm that i found all the other astronomers gathered around the TV watching CNN. i was surprised, to say the least, when i heard the news that columbia had broken apart during re-entry! most of the visiting astronomers and observatory staff there were very emotional about the event. this created a somber atmosphere as we discussed the effect of the 3000 degree heat generated during re-entry and our speculations as to what could have happened. as the shock slowly wore off and the reality set in, i reflected on my thoughts that early morning as i waited to see the shuttle.
i think professor astronomy sums them up, and provides excellent insight into these events... so i will leave you with a quote from his blog:
1) on January 28, 1986, the shuttle Challenger exploded. i was young at the time, but i have a very vivid memory of the moment. my class was privileged to watch the launch live and we were all very excited! i sat on the floor, next to my best friend jessica, looking up at the TV. the image of the liftoff and the arc made by the smoke in the air is very vivid in my mind. then the line grew into an unexplainably big puff ball while white streaks shot out to the sides.
the explosion seemed surreal and confusing. my young mind's first thought was "that's odd. i don't think that was supposed to happen." it was ultimately the reaction of the teachers in the room that made me understand the seriousness of the situation. i remember deciding at that moment that i did NOT want to be an astronaut!
2) On February 1, 2003 i was in west texas observing at the mcdonald observatory. i was there for an 8-night observing run on the 2.7m telescope and became excited when i heard the shuttle columbia would pass over texas on its way to landing in florida! depending on the shuttle's final descent path, i would be able to see it crossing the sky, low to the north, early in the morning. i followed NASA's liftoff webpage all night to track columbia in its orbit, in anticipation of seeing the shuttle! while i finished up some morning calibration exposures, i stood out on the catwalk that surrounds the telescope.... looking off to the north.
NASA estimated that the shuttle would pass by between 7:30 and 8am (central time, of course), so i watched from about 7:30 until 8:15am (it was february and cold on the mountain top!). The sun had risen by 8am and since the shuttle would have crossed the sky very low on the horizon, i suspected that i would not see it at all. so i finished the night's observing a little disappointed having not seen the shuttle. i closed down the telescope, walked across the road to my dorm room and went straight to sleep. it wasnt until i woke up around 4pm that i found all the other astronomers gathered around the TV watching CNN. i was surprised, to say the least, when i heard the news that columbia had broken apart during re-entry! most of the visiting astronomers and observatory staff there were very emotional about the event. this created a somber atmosphere as we discussed the effect of the 3000 degree heat generated during re-entry and our speculations as to what could have happened. as the shock slowly wore off and the reality set in, i reflected on my thoughts that early morning as i waited to see the shuttle.
i think professor astronomy sums them up, and provides excellent insight into these events... so i will leave you with a quote from his blog:
It is important to remember these people and accidents. These men and women willingly put their lives at risk to explore space, bravery that deserves recognition. But also, each of these accidents may have been preventable. A string of human errors and cultural issues led to each accident. These errors are much easier to see in retrospect than they were ahead of time, and so we should be careful in assigning blame to freely. Yet we can and must learn from these mistakes to protect future lives; to ignore these lessons would be an unforgivable failure.
Finally, we should all recognize that more lives will be lost in the future. Space travel is extraordinarily dangerous. As private companies also begin to open space to civilians, we must accept that there will be accidents and lives lost, and most of these will probably be due to human error. Let's just hope that those errors are due to exploration and humankind's pushing of the envelope, and not due to our failure to learn from our history.
when imagination becomes reality
here is an amazing project where Yeon Doo Jung, a korean photographer, takes drawings by children and turns them into reality by staging real photoshoots! that must be such a cool feeling as a kid to have so much effort going into creating your personal design! see more at wonderland 2005...
i found this via neat-o-rama
i found this via neat-o-rama
Friday, February 1, 2008
carnival o space - #39
this week's collection of astronomy musings has been collected at sean welton's visual astronomy.
around christmas, many people asked me about what kind of telescope they should buy for their backyard sky watching. assuming the successful purchase of a telescope, i refer you to sean's excellent list of ten essential astronomy accessories. i find especially useful: a good chair, star charts, a red flashlight, warm clothes and various eye pieces. one thing that doesnt make his top ten, but i definitely enjoy when possible, is a tasty beverage kept warm or cold in a good thermos! enjoy!
around christmas, many people asked me about what kind of telescope they should buy for their backyard sky watching. assuming the successful purchase of a telescope, i refer you to sean's excellent list of ten essential astronomy accessories. i find especially useful: a good chair, star charts, a red flashlight, warm clothes and various eye pieces. one thing that doesnt make his top ten, but i definitely enjoy when possible, is a tasty beverage kept warm or cold in a good thermos! enjoy!
Thursday, January 31, 2008
Wednesday, January 30, 2008
a long time ago, in galaxies far, far away...
would you, could you be in austin, texas on friday, feb. 8th?? if so, then read on!
you're invited to a public astronomy lecture i'm giving for the austin astronomical society in a couple weeks! At 7:30pm on the evening of friday, february 8th, i'll be talking for 45 minutes about galaxy evolution and answering questions afterwards. No prior astronomy knowledge is necessary... enthusiasm is encouraged! :)
Title: "A long time ago in galaxies far, far, away..."
Topic: Galaxies found in the distant, early universe look and behave differently from those in our local universe. In this presentation, I describe triumphs and tribulations towards our understanding of these differences, by highlighting some fundamental insights into the current questions of galaxy evolution.
Treatise: Astronomy always fascinated Amanda as a child, but she never thought that it could be a feasible career. As an undergraduate at the University of Cincinnati, she studied French for a year before recognizing her true fascination with the Universe. She changed her major to physics, having no real idea of what she was getting herself into! Ten years later, she is preparing to graduate from the University of Texas at Austin with her PhD in Astronomy, still not entirely sure of what the Universe has in store for her, but excited to find out!
The meeting location is in RLM Room 4.102 (The Wheeler Lecture Hall), in the Robert Lee Moore Building, on the University of Texas at Austin campus at the southeast corner of Dean Keeton (26th) and Speedway. more info here:
http://www.austinastro.org/meetings.html
map and parking:
http://www.austinastro.org/meetings-map.gif
see you there!!
amanda
you're invited to a public astronomy lecture i'm giving for the austin astronomical society in a couple weeks! At 7:30pm on the evening of friday, february 8th, i'll be talking for 45 minutes about galaxy evolution and answering questions afterwards. No prior astronomy knowledge is necessary... enthusiasm is encouraged! :)
Title: "A long time ago in galaxies far, far, away..."
Topic: Galaxies found in the distant, early universe look and behave differently from those in our local universe. In this presentation, I describe triumphs and tribulations towards our understanding of these differences, by highlighting some fundamental insights into the current questions of galaxy evolution.
Treatise: Astronomy always fascinated Amanda as a child, but she never thought that it could be a feasible career. As an undergraduate at the University of Cincinnati, she studied French for a year before recognizing her true fascination with the Universe. She changed her major to physics, having no real idea of what she was getting herself into! Ten years later, she is preparing to graduate from the University of Texas at Austin with her PhD in Astronomy, still not entirely sure of what the Universe has in store for her, but excited to find out!
The meeting location is in RLM Room 4.102 (The Wheeler Lecture Hall), in the Robert Lee Moore Building, on the University of Texas at Austin campus at the southeast corner of Dean Keeton (26th) and Speedway. more info here:
http://www.austinastro.org/meetings.html
map and parking:
http://www.austinastro.org/meetings-map.gif
see you there!!
amanda
jupiter and venus under your finger!
this friday morning... feb 1, 2008... get up early and go outside! the very bright "morning star," venus, and the very large and bright planet, jupiter, are creeping closer to each other these days! they will be closest this friday morning with a separation of less than one degree!.... that means they will both be covered by one finger when you hold it out at arms length! here are a couple maps to help you find you way. look to the southeast at dawn....
the morning light should provide a perfect photographic setting! here's an image i saw at NASA's science site taken by Thierry Demange in france on january 23.
the morning light should provide a perfect photographic setting! here's an image i saw at NASA's science site taken by Thierry Demange in france on january 23.
Tuesday, January 29, 2008
powers of ten - galaxy song
the first video is the fabulous "powers of ten" video produced by architects charles and ray eames in 1977. this 10 minute feature shows the scale of the universe, from a cell in our body, to a galaxy out in space!
"Eventually, everything connects." — Charles Eames
this couple minute video shows the "powers of ten" movie while playing the brilliant "galaxy song" by eric idle. just as carl sagan's COSMOS has stood up the test of time, Paul Kohlmiller tells us that the galaxy song does too!
here's the original version of the "galaxy song", shown in the monty python classic film... "the meaning of life".
"Eventually, everything connects." — Charles Eames
this couple minute video shows the "powers of ten" movie while playing the brilliant "galaxy song" by eric idle. just as carl sagan's COSMOS has stood up the test of time, Paul Kohlmiller tells us that the galaxy song does too!
here's the original version of the "galaxy song", shown in the monty python classic film... "the meaning of life".
Monday, January 28, 2008
NASA "meatball" logo
i just read the print on the back of a NASA sticker i picked up at the AAS meeting in austin. i learned that the NASA insignia was designed in 1959 and has been referred to as the "meatball" since 1975!? the sphere represents a planet, the stars represent space, the red chevron wing represents aeronautics (the latest design in hypersonic wings at the time the logo was developed), and the spacecraft orbiting around the wing represents space travel.
i spy with my little eye, three stars close together in a line....
i still dont quite understand how the word "meatball" fits into this insignia, but i give huge props to NASA anyway, for giving out some great stuff this year at AAS! the calendar i picked up is fantastic, the image changing COBE/WMAP postcard is cool, and i love my little black cleat bag! thanks NASA! (where is this kind of positive press for NASA in the popular media?)
i spy with my little eye, three stars close together in a line....
i still dont quite understand how the word "meatball" fits into this insignia, but i give huge props to NASA anyway, for giving out some great stuff this year at AAS! the calendar i picked up is fantastic, the image changing COBE/WMAP postcard is cool, and i love my little black cleat bag! thanks NASA! (where is this kind of positive press for NASA in the popular media?)
Saturday, January 26, 2008
focus
what i strive for,
what i sometimes lack.
my excuse for many things,
my determination for others.
what motivates my intuition,
what hinders my instincts.
i'm driven by curiosity,
i'm delighted by discovery.
satisfaction is my motive,
happiness is my goal.
what i sometimes lack.
my excuse for many things,
my determination for others.
what motivates my intuition,
what hinders my instincts.
i'm driven by curiosity,
i'm delighted by discovery.
satisfaction is my motive,
happiness is my goal.
Friday, January 25, 2008
our moon and mercury
congratulations! everyone fared very well on this week's mercury or the moon game! without further hesitation... the bottom image in the game was mercury and the top was the moon! now its time to take a closer look at their similarities and differences between these two neighbors of ours.
take another guess....
could you tell the difference between them in the new images above? this time i think it's a bit easier because only the second image... the moon... reveals the sharp-edged darker regions called maria. the low-laying maria are flat planes that appear smooth in the image because they have fewer crater impacts.
there are a few maria visible on mercury, but they are small and not so defined. the striking brightness variations on mercury's surface might be caused by different things.
some people identify familiar objects on the surface of the moon based on the patterns resulting from the strong contrast between the dark maria, and the bright hilly highlands. i've never been able to find the man in the moon on my own. i think this phenomenon is somewhat subjective since people tend to find faces among patterns easily, but also because i'm always so distracted by the realization that the moon is a big huge rock flying around us in gigantic, predictable circles... that my eyes tend to not seek familiarity!
an obvious similarity between our two neighbors is their dense covering of impact craters. they both have large craters that are covered with smaller, younger craters. the fact that we can still see these craters tells us that neither object experiences strong storms caused by thick atmospheres, or lingering geologic activity. it appears to me from closer inspection of their surfaces, that mercury has more little tiny craters than the moon.
there are a couple very large impact sites seen on the moon. two of these seem much bigger than the largest impacts on the surface of mercury. the moon's largest impact craters also have large radial white lines shooting from them, caused by debris material thrown out at impact. i see some of these lines on mercury, but they are much fainter. i think this can be explained by mercury's higher surface gravity.
the planet mercury is larger than our moon. i can apply newton's law of universal gravitation to determine the relative strengths the gravitational forces one would feel on the surface of each orb...
if i'm sitting on mercury, then i say my mass is M1 in the equation above, mercury is M2 and the radius of mercury is r. I do the same thing for the moon and take the ratio of their F_. i discover that i weigh a little over 2 times more on mercury than i would on the moon! higher surface gravity means that the impacts on mercury did not throw debris as far as they did on our moon, and we see weaker white streaks coming out from each crater! it's interesting though that the brightest lines on mercury seem to radiate from very small impact craters.
what other differences do you see?
take another guess....
could you tell the difference between them in the new images above? this time i think it's a bit easier because only the second image... the moon... reveals the sharp-edged darker regions called maria. the low-laying maria are flat planes that appear smooth in the image because they have fewer crater impacts.
there are a few maria visible on mercury, but they are small and not so defined. the striking brightness variations on mercury's surface might be caused by different things.
some people identify familiar objects on the surface of the moon based on the patterns resulting from the strong contrast between the dark maria, and the bright hilly highlands. i've never been able to find the man in the moon on my own. i think this phenomenon is somewhat subjective since people tend to find faces among patterns easily, but also because i'm always so distracted by the realization that the moon is a big huge rock flying around us in gigantic, predictable circles... that my eyes tend to not seek familiarity!
an obvious similarity between our two neighbors is their dense covering of impact craters. they both have large craters that are covered with smaller, younger craters. the fact that we can still see these craters tells us that neither object experiences strong storms caused by thick atmospheres, or lingering geologic activity. it appears to me from closer inspection of their surfaces, that mercury has more little tiny craters than the moon.
there are a couple very large impact sites seen on the moon. two of these seem much bigger than the largest impacts on the surface of mercury. the moon's largest impact craters also have large radial white lines shooting from them, caused by debris material thrown out at impact. i see some of these lines on mercury, but they are much fainter. i think this can be explained by mercury's higher surface gravity.
the planet mercury is larger than our moon. i can apply newton's law of universal gravitation to determine the relative strengths the gravitational forces one would feel on the surface of each orb...
if i'm sitting on mercury, then i say my mass is M1 in the equation above, mercury is M2 and the radius of mercury is r. I do the same thing for the moon and take the ratio of their F_. i discover that i weigh a little over 2 times more on mercury than i would on the moon! higher surface gravity means that the impacts on mercury did not throw debris as far as they did on our moon, and we see weaker white streaks coming out from each crater! it's interesting though that the brightest lines on mercury seem to radiate from very small impact craters.
what other differences do you see?
low-G rides!
the fact that independent organizations are creating technology to go to space is awesome! friendly competition, in my opinion, can only benefit the potential for space travel by introducing more clever and efficient designs, that arent held back by the federal requirements faced by NASA and other worldwide, government-funded organizations!
here's an example... virgin galactic's SpaceShipTwo:
i'm not saying i'll be first in line to jump on the SpaceShipTwo next year when it launches. i dont have an extra $200,000 in my financial future, and i'm concerned enough with self-preservation to wait until they work out some of the bugs in the process (but seriously, if anyone wants to see an astropixie in space sooner than if she pursues the possibility of becoming a real astronaut.... please let me know). i know of another scientist who enjoys weightlessness: stephen hawking!
here's a flight simulation video from virgin galactic:
i wonder what the point is of raising the tail wings once in orbit since they lower them again to land. its seems that they would just block the view from inside the spacecraft! also, can you choose what side of the earth you fly over during your 4 minutes of weightlessness? (do i have a choice of color for my space suit shoes? is there a different, less bug-eye design for the helmet??) see more photos here.
here's a simulation of another potential low-G ride, called the spacedev dreamchaser designed by a different group, the benson space company.
this spacecraft seriously needs more windows... and a better theme song! otherwise, i'm glad to see competition in the field!
i'm eager to see what develops from these independent groups working towards space flight!
here's an example... virgin galactic's SpaceShipTwo:
i'm not saying i'll be first in line to jump on the SpaceShipTwo next year when it launches. i dont have an extra $200,000 in my financial future, and i'm concerned enough with self-preservation to wait until they work out some of the bugs in the process (but seriously, if anyone wants to see an astropixie in space sooner than if she pursues the possibility of becoming a real astronaut.... please let me know). i know of another scientist who enjoys weightlessness: stephen hawking!
here's a flight simulation video from virgin galactic:
i wonder what the point is of raising the tail wings once in orbit since they lower them again to land. its seems that they would just block the view from inside the spacecraft! also, can you choose what side of the earth you fly over during your 4 minutes of weightlessness? (do i have a choice of color for my space suit shoes? is there a different, less bug-eye design for the helmet??) see more photos here.
here's a simulation of another potential low-G ride, called the spacedev dreamchaser designed by a different group, the benson space company.
this spacecraft seriously needs more windows... and a better theme song! otherwise, i'm glad to see competition in the field!
i'm eager to see what develops from these independent groups working towards space flight!
carnial of space - 38
this weeks spacey entries are cleverly mixed into sam wise's mystery narrative, the adventures of shorty barlow, private eye. enjoy!!
Thursday, January 24, 2008
interest and rejection
i knew my looming dissertation defense and job-application period would provide a lot of moment-to-moment excitement in my life, but somehow i didnt anticipate the degree of my emotional highs and lows! i've finished applying for the majority of post-doctoral positions now, and am eagerly awaiting the results. i applied for about 20 positions and i've heard back from many of them. the unofficial-official date in the US for job offers in astronomy is february 15th. international posts tend to work on slightly different time frames, but they know that most applicants for US "prize fellowships" (hubble, spitzer, NSF, chandra, etc...) will hold out at least until the beginning of february to hear from these fellowships!
last week, i was disappointed to receive a scathing rejection *email* from one of the prize fellowship committee, reminding all of us applicants that any variation on the detailed application format was highly frowned upon. i understand this complaint from people who are reading over 100 5-page applications, but the message seemed so negative... especially compared to the email i received last night. this was absolutely the most wonderfully-worded rejection letter i could ever receive, starting out with....
i was so sad when i reached the gigantic BUT part of the letter. oh well.
the thing that gets me more than receiving a constructive-criticism-negative-rejection letter, is receiving absolutely no acknowledgement what-so-ever! i've worked on detailed applications, asked very busy collaborators to write me letters of recommendation, and then i've heard absolutely no response from multiple places. it's horrible to hear offers made to other people via the astrophysics job rumor mill but hear nothing personally!! it's like not calling someone back who asks you out on a date, just because you think it will let them down easier! i think thats horrible!! just tell me "no" so i can deal with it and move on!
aside from all this venting, i feel confident i will get a job that i will be perfectly happy with.... it's just a roller coaster ride to find it!
anyway, i've been ridiculously busy with planning my defense, interviewing for jobs, and teaching classes, so i havent been able to update as much as i'd like. the good news is that i met with my committee today and set a final date for my dissertation defense.... may 15th. eek! i will be ready by that point. it seems far away, but my family wanted to reserve plane tickets to come down and support me... which i very much appreciate!!
i came home tonight and celebrated the official date by opening my last bottle of fantastic chilean wine. woo hoo! cheers!
last week, i was disappointed to receive a scathing rejection *email* from one of the prize fellowship committee, reminding all of us applicants that any variation on the detailed application format was highly frowned upon. i understand this complaint from people who are reading over 100 5-page applications, but the message seemed so negative... especially compared to the email i received last night. this was absolutely the most wonderfully-worded rejection letter i could ever receive, starting out with....
My colleagues and I were very grateful to receive your impressive application, which is supported by strong letters of reference that indicate how highly your professors regard you and your research.
i was so sad when i reached the gigantic BUT part of the letter. oh well.
the thing that gets me more than receiving a constructive-criticism-negative-rejection letter, is receiving absolutely no acknowledgement what-so-ever! i've worked on detailed applications, asked very busy collaborators to write me letters of recommendation, and then i've heard absolutely no response from multiple places. it's horrible to hear offers made to other people via the astrophysics job rumor mill but hear nothing personally!! it's like not calling someone back who asks you out on a date, just because you think it will let them down easier! i think thats horrible!! just tell me "no" so i can deal with it and move on!
aside from all this venting, i feel confident i will get a job that i will be perfectly happy with.... it's just a roller coaster ride to find it!
anyway, i've been ridiculously busy with planning my defense, interviewing for jobs, and teaching classes, so i havent been able to update as much as i'd like. the good news is that i met with my committee today and set a final date for my dissertation defense.... may 15th. eek! i will be ready by that point. it seems far away, but my family wanted to reserve plane tickets to come down and support me... which i very much appreciate!!
i came home tonight and celebrated the official date by opening my last bottle of fantastic chilean wine. woo hoo! cheers!
Tuesday, January 22, 2008
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