There is a group here at Goddard is called the HEASARC – High Energy Astrophysics Science Archive Research Center. This is where we keep data from old and new satellites. Even though every new satellite is an improvement over the last in one way or another, it is important to keep old data, with the expertise to go with it.
Think of Halley’s Comet – when Edmund Halley calculated the orbit of this comet from observations in 1682, he was able show that it was the same as the comets of 1531 and 1607 because there were sufficiently detailed records from those appearances.
Halley’s Comet. Credit: NASA
We now know of even earlier appearances of Halley’s Comet, dating back at least to the Chinese record of of a comet in 240 BC. Chinese court astrologers had a habit of making careful records of not only comets but novae and supernovae, which they collectively called “guest stars.” These records are invaluable to today’s astrophysicists who also use modern telescopes and satellites. For example, historical records can give you the precise age of a supernova since the explosion.
The Universe is expanding faster and faster and faster! But, how do we know that? Our current knowledge of the Universe is built upon a foundation of research done by previous generations of scientists. Sometimes it seems that science moves slowly, but when you look back, it becomes clear just how far we have come in a short of time. (When you’re an astronomer, anything less than a few million years is very short!)
NASA’s Cosmic Times project takes a look at how our understanding of the Universe has changed from 1919, when astronomers believed the Universe was the size of our galaxy and infinitely old, to today, when astronomical evidence shows that the Universe is about 94 billion light years in size and about 14 billion years old. Cosmic Times traces these changes through a series of front-page newspapers from six different times over the past century.
Go find out how astronomers have come to their current understanding of the size, age, and nature of the Universe! What will we find out in the next 10 years?
The last time I visited an observatory, it was an ancient Chinese one. This time I visited one a little closer to home.
When I learned that I was going to be in Southern California (visiting my husband who was there for back-to-back science conferences), I knew I had to stop at Palomar Observatory! After all, back in college, I spent a chunk of one semester of Astronomy class in the basement of Davey Lab using a jeweler’s loupe searching for quasars on old POSS (Palomar Observatory Sky Survey) plates. (And that way lies madness.)
It turned out to be well-worth a visit. The main attraction at Palomar is the giant Hale telescope, which lives in the biggest dome there. And it’s truly impressive. The Hale telescope has 5.1 m (200 inch) mirror and is named for George Ellery Hale, the man who was behind the creation of the observatory. In fact, it was the largest telescope in the world for a long time, until Keck I on Mauna Kea was built in the early 90s.
We all know that Nicolaus Copernicus revolutionized our view of the universe. Who would you pick as the top scientists who further developed astronomy during the 16th and 17th centuries? I would pick Tycho Brahe, Johannes Kepler, Galileo Galilei, Isaac Newton, and Edmond Halley as my top five. I got to think about these giants of the field during my recent European trip, as I had the chance to see sights connected directly to three of these five, and indirectly to a fourth.
Halley’s major contribution was that he calculated the orbit of the comet that now bears his name – he applied his friend Newton’s laws of physics, and realized that the comet of 1682 had previously been seen in 1531 and in 1607, and predicted, correctly, its return in 1758. In this, he went beyond Newton and included the approximate effect of the gravity of Jupiter.
During its return in 1986, several spacecraft visited Halley’s comet, including European Space Agency’s Giotto mission. When a space probe is named after a person, that person usually is a famous scientist. In this case, though, ESA picked Giotto, who was an architect and a painter, and I got to see one of his masterpieces, the Scrovegni Chapel in Padua (Padova), Italy. Giotto painted many religious scenes in the year 1305 or so in the interior of this chapel. In one of them, the Adoration of the Magi, he incorporated his interpretation of the star of Bethlehem – a comet. This is widely thought to have been inspired by the sight of Halley’s comet from its appearance in 1301, 5 orbits before Halley saw it, and 9 orbits before Giotto the spacecraft would visit it.
Here are a few pretty astronomical images that are Valentine themed!
This image shows a ring… of black holes!
Credit: X-ray: NASA/CXC/MIT/S.Rappaport et al, Optical: NASA/STScI
This object is known as Arp 147 – it’s actually a pair of interacting galaxies, a spiral one on the right, that collided with the elliptical one on the left. The image contains X-ray data from Chandra (pink), and optical data from the Hubble (red, green, blue). The collision caused a wave of star formation visible here as a blue ring containing many massive young stars. In just a few million years, these stars can speed through their evolutionary cycle, exploding as supernovae and leaving neutron stars and black holes behind! Neutron stars and black holes that have companion stars can become bright sources of X-rays. You can see nine (pink) X-ray sources scattered around the blue ring. They are so bright in X-rays that they are likely black holes. There is more information on the Chandra site.
Check out this amazingly cool orrery, created by the creative director, of Dynamic Diagrams, Piotr Kaczmarek. It shows the motion of the planets in our solar system. You can change it by setting the date, and you can speed it up or slow it down! You can even click on the lower right hand-corner and change it from the Copernican view to the earth-centric Tychonian view! (Be sure to try tracing the planets orbits in this view!) What a cool app! (BTW, if you can’t see it, it’s because it’s Flash.) Here’s a direct link to the orrery flash file.
There are many different meetings and conferences for professional astronomers, but one of the most widely attended is the American Astronomical Society (AAS) meeting. These are held twice a year, in June and January, though January is better attended. The location of the meeting changes each time, but every four years it’s in Seattle, WA. (Washington, DC hosts winter AAS every four years too – last year the meeting was in DC and we made a podcast episode about what the meeting was like!)
This year, I traveled to Seattle to attend the meeting. This was pretty cool, because I’d never been to Seattle before, and I was able to take some time off to sight-see before and after the meeting.
It’s 1 PM, and I’m sampling the local cuisine, 7000 miles from home and 50 km from my second home outside Tokyo, hoping I can make it back before dark on my rented bicycle. Hi everybody, I’m new to Blueshift, but not new to Japan. I’ve been coming over to the Institute for Space and Astronautical Science (ISAS) since the late 90′s, working first on the Astro-E mission, then Astro-E2 and now Astro-H. These are all X-ray astronomy satellites, and they all make use of a microcalorimeter spectrometer built at Goddard.
Use of a s-what? A spectrometer, which measures the spectrum of incoming light (or in this case, X-rays). That is, it measures the energy of each X-ray photon it sees. For X-ray astrophysicists, the most important information is in the spectrum. Sadly, the usual methods of measuring a detailed X-ray spectrum are inefficient, so you have to expose the sensor for days to get a useful signal. What you wish you could do is catch all the photons and accurately measure each one. That’s where the microcalorimeter part comes in. You might have used a calorimeter in chemistry class to measure the heat of a reaction. Our microcalorimeters work the same way, only they measure the heat of a single photon. The higher the energy of the photon, the more heat.
I love astronaut ice cream – that freeze-dried, crispy block of strawberry, vanilla, and chocolate sugary sweetness that melts on your tongue into something that vaguely resembles melted ice cream. Though it was developed for the Apollo program, I was disappointed to find out that it wasn’t very popular and isn’t a part of the regular NASA menu. There are actually some fairly stringent requirements for food that goes into space. You can read more and find some excellent links to menus and space food science in this web feature.
When I heard that they filmed part of an elimination challenge for the latest season of Top Chef right here at NASA Goddard Space Flight Center, I was jealous! Vickie Kloeris came up from Johnson Space Center in Houston and joined the panel of judges (including Buzz Aldrin!) to choose a dish that could be served in zero gravity. I would’ve loved to get a taste of those amazing meals, either in DC or up in space. Unlike the “Hubble Gotchu” filming, we didn’t find out about this one until it was over – so we didn’t get the behind-the-scenes scoop. I’ve been waiting to see this episode for a few months!
If you didn’t catch the episode last night, it’s currently available streaming online. I don’t know how long that will last – so check it out below!