All posts by Tom

An Interview with Venetia Burney Phair

For those of you who don’t know, Venetia Burney Phair was an accountant and taught economics and math to school girls.

She at age 11 is the person who gave Pluto its name. This interview was recorded in 2006.

Sadly Venetia  passed away on 30 April 2009.

This interview and more is  available at the New Horizons site.

Audio: NASA

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

Countdown to Pluto – Update

Here’s the 16 June 2015 edition.

The flyby of 14 July is less than a month out.

Topics include a mission and science overviews, a look at the spacecraft and its seven science instruments, and what we know about Pluto to date.

The part talking about sending commands to where the spacecraft is “going” to be after signal travel time is pretty amazing.

Video

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

Teenage Quasars

Quasars in Interacting Galaxies
Source: Hubblesite.org

It’s always nice when a Hubble release features a scientist at a home town school.  Bravo!

From Hubblesite:
Quasars are the light fantastic. They are the brightest beacons in the universe, blazing across space with the intrinsic brightness of one trillion suns. Yet the objects are not vast galaxies, but they appear as pinpoint sources in the biggest telescopes of today — hence the term “quasar” for quasi-stellar object. Discovered in the 1960s, it took more than two decades of research to come to the conclusion that quasars are produced by the gusher of energy coming from over-fed supermassive black holes inside the cores of very distant galaxies. And, most quasars bloomed into a brief existence 12 billion years ago.

The big question has been, why? What was happening in the universe 12 billion years ago? The universe was smaller and so crowded that galaxies collided with each other much more frequently than today. Astronomers using Hubble’s near-infrared vision tested this hypothesis by looking at dusty quasars where their glow was suppressed by dust, allowing a view of the quasar’s surroundings. Hubble’s sharp vision revealed chaotic collisions between galaxies that gave birth to quasars by fueling a supermassive central black hole.

“The Hubble observations are definitely telling us that the peak of quasar activity in the early universe is driven by galaxies colliding and then merging together,” said Eilat Glikman of Middlebury College in Vermont. “We are seeing the quasars in their teenage years, when they are growing quickly and all messed up.”

Read the full story.

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

The Lone Hill

ceresoi6

One of the latest Dawn spacecraft images shows what appears to be a lone hill on the surface of Ceres. The “hill” seems to be oddly out of place with all the visible terrain in the image. Hopefully down the road we will get topographical data on this feature.

This particular image was taken with the framing camera on 06 June 2015 from an altitude of 4,400 km / 2,700 miles and has a resolution down to 410 meters / 1400 feet per pixel.

Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

Happy Spring!

marsrovers

No not here, today is the first of Spring on Mars!

Determining the seasons on Mars isn’t difficult to understand but is a little complicated to explain and The Planetary Society has already done an excellent job at the task I recommend you go to their Mars Calendar page.

Also if you have been wondering about the lack of updates on the Rovers lately, Mars has been in solar conjunction. Mars is behind the Sun and hidden from us, it happens about every 28 months. When the solar conjunction occurs communications range from very difficult to impossible. The image above from the Mars Science Laboratory – Curiosity was taken on 03 June 2015 and is the last image recieved before the beginning of the conjunction. Mars will come out of the conjunction (hopefully) enough for communications to begin on 21 June.

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

First Generation Stars?

keckCR7

We generally think of stars in populations.

Population III stars are the hypothetical first stars. These stars are extremely metal poor but massive stars.

By metals we are talking about elements heavier than hydrogen (and helium depending on which definition you read and is what I consider to be a non-metal too). All elements heavier than hydrogen are a by-product or ash from fusion in the cores of stars.

Population II stars have little metals, stars in globular clusters are made up of a good percentage of population 2 stars. Population II stars are considered to have created all other elements in the periodic table beyond hydrogen and helium. Prior to 1978 or 1979 these were the stars thought to be the oldest stars and still are the oldest observed stars.

Population I stars are considered metal rich young stars and include our own Sun and are common in the arms of the Milky Way.

Now astronomers using the W. M. Keck Observatory, ESO’s Very Large Telescope, Subaru Telescope and the Hubble Space Telescope have discovered the brightest galaxy so far and have evidence of first generation stars within.

Details at the W.M. Keck Observatory site.

Image: David Sobral

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

All Smiles

Samantha Cristoforetti is all smiles on her return to Earth. I enjoyed following her activities during her stay aboard the ISS.

samantaback

From ESA:

ESA astronaut Samantha Cristoforetti, NASA astronaut Terry Virts and Russian commander Anton Shkaplerov landed safely on 11 June 2015 in the Kazakh steppe after a three-hour ride in their Soyuz spacecraft. They left the International Space Station at 10:20 GMT at the end of their six-month stay on the research complex.

Terry Virtz, Anton Shkaplerov, and Samantha Cristoforetti are returning after more than six months onboard the International Space Station where they served as members of the Expedition 42 and 43 crews.

Copyright ESA–S. Corvaja, 2015

 

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

Inside Tycho Crater

tycho

When we look up at the moon we can see the very large Tycho crater as above (image above wiki commons).

I’ve talked some about central peaks in recent posts and the Lunar Reconnaissance Orbiter has taken some spectacular images of Tycho at very close range. Click the image to see the central peak of Tycho from the LRO, that central peak is more than 2 km / 6562 ft high.

Not all craters have central peaks, it depends on the gravitational field of the body and the material being impacted and of course how large the impact is. Here is a very short video of the concept in a fluid. In rocky moons and planets the central peaks can be formed by the rock being pushed back up by the underlying substrate (rock) instead of the fluid in the video. It is very much like a rebound event.

There are lots of variables that play into the formation of central peaks. You can imagine if the impacted surface was say sandy regolith the peak would just fall down on itself and if the impacting body was not large enough material would be just swept away. Likewise an air burst meteor may not leave a central peak becuase the blast might not be concentrated enough. Even the angle of impact makes a difference.

So as you can see there is a lot to consider. Here is a great web page on crater forms from the University of Wisconsin – Green Bay.

The page where the above image of Tycho’s central peak came from gives a nice treatment of Shapes of Craters and there are even better shots of the central peak of Tycho from the LRO here.

Images: LRO / NASA

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

Rosetta’s View of the Comet

rosettaview

This is a view of Comet 67P/Churyumov-Gerasimenko just before receiving the long awaited signal from Philae on 13 June. Rosetta was just 201 km / 125 miles from the center of the comet at the time. The image has the small lobe to the right and the depression called Hatmehit is visible. Philae is thought to be situated near the top right of the image just outside the rim.

Philae is receiving enough sunlight to attain an acceptable operation temperature and generate electricity. The local “comet day” the power generated rises from about 13 watts at sunrise to a bit more than 24 watts. the power required to turn on the transmitter is 19 watts. I should note the comet has about a 12 hour rotation and the day light cycle is some portion of that and may be more or less than half the time. The time the solar panels receive power is 135 minutes during the daylight cycle.

While the information we have is very preliminary, it appears that the lander is in as good a condition as we could have hoped,” says Dr Ulamec.

Get all the details here.
Copyright ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

Tethys and Saturn

tethysandsat

A nice image from the Cassini spacecraft of the moon Tethys and Saturn.

The configuration shows two large craters on Tethys facing Saturn in sharp relief. The larger crater is the southern crater with a central peak indicating a violent impact. The northern crater does not seem to have a central peak so the impact wasn’t quite as violent or the surface composition did not support the central peak formation.

The moon is much closer to the spacecraft, Saturn is in the background. The distance to Tethys is about 120,000 km / 75,000 miles.

Today Cassini is doing a rather distant flyby of a few of Saturn’s smaller moons including: Polydeuces, Methone, Pan, Atlas and Telesto. We don’t get to see these very often so I hope they are close enough for images.

Image Credit: NASA/JPL-Caltech/Space Science Institute

facebooktwittergoogle_plusredditpinterestlinkedinmailby feather