Profile

Cover photo
Brian Grefenstette
Works at California Institute of Technology
Attended Stanford University
12,783 followers|436,299 views
AboutPostsCollections+1's

Stream

Brian Grefenstette

Shared publicly  - 
 
This came out a couple of weeks ago, but I'm just getting around to re-sharing now. Cool new #NuSTAR  results from observation of SN1987A. Granted, the press image is from Chandra/Hubble, but the fact that we see it as a point source doesn't lend itself to awesome images the way that Cas A did.



http://www.jpl.nasa.gov/news/news.php?feature=4577
NASA's NuSTAR, has found evidence that a massive star exploded in a lopsided fashion, sending ejected material flying in one direction and the core of the star in the other.
2
1
Dimitrios Diamantaras's profile photo
Add a comment...

Brian Grefenstette

Shared publicly  - 
9
2
Steve Berry's profile photoMarcus Ronaldi's profile photoChris Woodley's profile photo
2 comments
 
The Milky Way Galaxy is generally considered an Sbc-type galaxy. It has a central bulge of stars and spiral arms of gas and stars in a disk. We view the Milky Way essentially edge-on from our perspective near the plane of the disk and 28,000 light years from the Galactic center. In recent decades, Galactic astronomy has benefitted from a tremendous broadening of coverage of the electromagnetic spectrum by ground-based and spaced-based instruments. 
Add a comment...

Brian Grefenstette

Shared publicly  - 
 
Truth. Also relevant for proposal writing.

http://phdcomics.com/comics/archive.php?comicid=1796
5
1
Melvin Orihuela's profile photo
Add a comment...

Brian Grefenstette

Shared publicly  - 
 
NuSTAR’s solar observations are in the news again!
NuSTAR's solar observations are in the news again! There's been pretty good coverage of a NuSTAR contribution to the press conference today at the TESS meeting. Though I'm pretty sure that the scie...
2
Add a comment...

Brian Grefenstette

Shared publicly  - 
 
 
A new view of Comet 67P/C-G taken 20 April 2015 by Rosetta's NAVCAM from a distance of 128 km.

Details: http://blogs.esa.int/rosetta/2015/04/27/cometwatch-20-april/

Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

#Rosetta #67P #cometwatch  
3 comments on original post
1
Add a comment...

Brian Grefenstette

Shared publicly  - 
 
 
Why is The Sun's atmosphere 300x hotter than its surface?
Strong Evidence for Coronal Heating Theory Presented at 2015 TESS Meeting | NASA's EUNIS sounding rocket examined light from the sun in the area shown by the white line (imposed over an image of the sun from NASA's Solar Dynamics Observatory) then separated the light into various wavelengths (as shown in the lined images—spectra—on the right and left) to identify the temperature of material observed on the sun. The spectra provided evidence to explain why the sun's atmosphere is so much hotter than its surface.

April 28, 2015: The sun's surface is blisteringly hot at 10,340 degrees Fahrenheit—but its atmosphere is another 300 times hotter. This has led to an enduring mystery for those who study the sun: What heats the atmosphere to such extreme temperatures? Normally when you move away from a hot source the environment gets cooler, but some mechanism is clearly at work in the solar atmosphere, the corona, to bring the temperatures up so high.

Clear evidence now suggests that the heating mechanism depends on regular, but intermittent explosive bursts of heat, rather than on continuous gradual heating. This solution to the coronal heating mystery was presented in a media briefing on April 28, 2015, at the Triennial Earth-Sun Summit, or TESS, meeting in Indianapolis, Indiana.

This is the inaugural meeting for TESS, which is a first of its kind: uniting the various research groups that study the sun-Earth connection from explosions on the sun to their effects near our home planet and all the way out to the edges of the solar system—a research field collectively known as heliophysics. The overarching goal is to share techniques across disciplines and encourage interdisciplinary collaboration on outstanding heliophysics questions.

The coronal heating mystery is one such outstanding question. Four scientists spoke at the media briefing.

Jim Klimchuk, a solar scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, explained that the new evidence supports a theory that the sun's corona is heated by tiny explosions called nanoflares. These are impulsive heating bursts that individually reach incredibly hot temperatures of some 10 million Kelvins or 18 million degrees Fahrenheit—even greater than the average temperature of the corona—and provide heat to the atmosphere. The research evidence presented by the panel spotted this super hot solar material, called plasma, representative of a nanoflare.

"The explosions are called nanoflares because they have one-billionth the energy of a regular flare," said Klimchuk. "Despite being tiny by solar standards, each packs the wallop of a 10 megaton hydrogen bomb. Millions of them are going off every second across the sun, and collectively they heat the corona."

The first evidence of the presence of this super hot plasma was presented by Adrian Daw, a solar scientist at Goddard and principal investigator of the Extreme Ultraviolet Normal Incidence Spectrograph, or EUNIS, sounding rocket mission. EUNIS flew on a 15-minute flight in December 2013 equipped with an instrument called a spectrograph, which can gather information about how much material is present at a given temperature. The EUNIS spectrograph was tuned into a range of wavelengths useful for spotting material at temperatures of 18 million F, the temperatures that signify nanoflares. The spectrograph unambiguously spotted this extremely hot material in active regions that visibly appeared to be quiet.  In a quiet region, such hot temperatures clearly weren't due to a large explosive solar flare, and so are a smoking gun that something otherwise unobservable was heating up this area.

Daw also reported the results from another experiment launched on sounding rockets in 2012 and 2013 that imaged soft X-rays from the corona. These results, too, confirmed the presence of super hot plasma on the sun.

Iain Hannah, an astrophysicist at the University of Glasgow in Scotland, spoke about NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, which typically examines X-rays from distant stars and black holes. However, it is also capable of observing the much brighter light of the sun—something most astronomical observatories can't do.

"X-rays are a direct probe into the high-energy processes of the sun," said Hannah. 

NuSTAR saw X-rays that are signatures of super hot plasma in non-flaring active regions. While the sounding rocket experiments observed the energy produced by these nanoflares, NuSTAR is also able to look for the X-ray signatures of energetic particles.  Understanding what and how particles are accelerated out from these smaller nanoflare explosions can help scientists understand what processes create them.

Stephen Bradshaw, a solar astrophysicist at Rice University in Houston, Texas, was the last speaker. Bradshaw used a sophisticated computational model to demonstrate why spotting signatures of the nanoflares has been so difficult and how the new evidence will help researchers go forward to improve theories on the details of coronal heating—one day allowing heliophysics researchers to at last solve the coronal heating mystery.

The TESS meeting will occur every three years and is a joint meeting of the Space Physics and Aeronomy Section of the American Geophysical Union and the Solar Physics Division of the American Astronomical Society.

For more information about the TESS meeting, visit:
https://aas.org/meetings/tess2015

Credit: NASA/EUNIS/SDO/Goddard

+NASA Goddard 
+SDO | Solar Dynamics Observatory 
 
#NASA   #Space  #Satellite #Science #Sun #Solar #Atmosphere
#Corona #Heliophysics #EUNIS #Sounding #Rocket
#SolarDynamicsObservatory #SDO   #NuSTAR   #Nanoflares   #GSFC #Goddard
3 comments on original post
1
Add a comment...
Have him in circles
12,783 people
Oscar Cruz's profile photo
Ryan Partridge's profile photo
Chris Visagie's profile photo
Ryan Peterson's profile photo
Tycko Franklin's profile photo
Mark Wheeler's profile photo
Adrian Alexandru's profile photo
Carsten Ritter's profile photo
Jinath Premaratne's profile photo

Brian Grefenstette

Shared publicly  - 
 
Oohh..collections. When did this drop on Google+? Obviously I've been away too long..
1
Daniel Sprouse's profile photoSarah Carlton (Formerly Sarah Pagan)'s profile photo
2 comments
 
It's been maybe a week or two? And I don't think they're irritating. Unlike Facebook, whenever Google plus adds new features, they're not forced. You don't have to use collections.
Add a comment...

Brian Grefenstette

Shared publicly  - 
 
 
On May 5, 1961, Alan Shepard became the first American in space.

While NASA has been sending American astronauts into space for over half a century, it all began with one - Alan Bartlett Shepard, Jr. An American test pilot, Shepard was selected as one of the first seven astronauts by the then newly formed National Aeronautics and Space Administration. Coined the ‘Mercury 7’, NASA’s first batch of carefully selected and trained individuals were to pilot the manned spaceflights of the Mercury program. In January 1961, Alan Shepard was selected from this group to pilot the Freedom 7 mission which would make him not only the first American in space, but the first human to reach this threshold.

Unfortunately, due to delays by unplanned preparatory work, the flight was postponed nearly seven months after the initial planned date. In this time, more specifically less than a month prior to Shepard’s flight, Soviet cosmonaut Yuri Gagarin would leapfrog Shepard to become the first person in space and to orbit the Earth. On May 5, 1961, Shepard piloted the Freedom 7 mission and became the second person, and the first American, to travel into space.

Following his involvement with Mercury and Gemini, Shepard would command America’s third successful lunar landing mission - Apollo 14. The first mission to successfully broadcast color television pictures from the surface of the Moon, Shepard piloted the Lunar Module Antares to the most accurate landing of the entire Apollo program.

Celebrate the career of Alan Shepard by telling Congress to increase NASA's budget: http://www.penny4nasa.org/take-action/

#Penny4NASA #NASA #Space #History #OnThisDay  
2 comments on original post
3
Add a comment...

Brian Grefenstette

Shared publicly  - 
 
 
Milky Way Emerges as Sun Sets over Paranal Observatory in Chile
In this new image dusk reveals a stunning night sky over ESO’s Paranal Observatory, home to the Very Large Telescope (VLT)—the flagship facility for European ground-based astronomy. As the Sun sets on the site The Milky Way is shown in magnificent detail. Although it appears to the naked eye as a clouded haze across the sky, The Milky Way consists of 100–400 billion individual stars strung out along its 100,000 light-year extent.

In this image, The Milky Way is a backdrop to the Unit Telescope number 4, also known as Yepun. Yepun is Venus in the Mapuche language, the language of the indigenous people from the south of Chile.

Yepun is one of four 8.2-meter telescopes that can be used together as one giant telescope, allowing astronomers to detect details up to 16 times finer than would be possible with the individual telescopes. Together, the VLT has stimulated a new age of discoveries, with several notable scientific firsts, including tracking individual stars moving around the supermassive black hole at the center of The Milky Way.

This image was taken by ESO Photo Ambassador John Colosimo.

Credit: ESO/J. Colosimo

+European Southern Observatory (ESO) 

#ESO   #Space   #Astronomy #Science #MilkyWay #Observatory #Paranal   #Telescope #Yepun   #Chile   #Atacama   #Cosmos #Universe
3 comments on original post
1
1
Chris Woodley's profile photo
Add a comment...

Brian Grefenstette

Shared publicly  - 
 
 
Yosemite under moonlight covered in fog
Rogelio: "Yesterday Saturday, around 9pm, feeling well rested I suddenly decided to head for a Yosemite night session...As I entered the park, as I was heading to my first location, I decided to stop at Tunnel View (a popular vista point in the park)...I set the camera, took a couple of pics and told myself "I'm going to come back here later and stay a while shooting... The fog is shifting nicely and The Milky Way will be up higher". I never went back but here's that one picture, Yosemite Valley under the Moonlight, covered in fog."

Credit: Rogelio Bernal Andreo
Rogelio's website: www.deepskycolors.com
Date: April 27, 2015

+Rogelio Bernal Andreo 

#Space #Astronomy #Science #MilkyWay #Galaxy #Earth #Yosemite #Valley #Glacial #Park #California #SierraNevada #Mountains #USA #UnitedStates #Astrophotography   #Art #Cosmos #Universe
27 comments on original post
4
1
Chris Woodley's profile photo
Add a comment...

Brian Grefenstette

Shared publicly  - 
 
 
BLOG: I'm going to be a dad for a second

This has been on my mind for the last few days, as I’ve watched a loud and determined bunch of unhappy people do their best to make happy and successful people feel as bad as they do. Everyone who becomes a fully-functioning adult — every single one of us…
This has been on my mind for the last few days, as I've watched a loud and determined bunch of unhappy people do their best to make happy and successful people feel as bad as they do. Everyone who becomes a fully-functioning adult -- every single one of us -- goes through a time in our lives when we are a shit. The difference between shitty adults and awesome adults is growing out of that.  Take charge of your life, and make changes to make yours...
34 comments on original post
1
Add a comment...
Brian's Collections
People
Have him in circles
12,783 people
Oscar Cruz's profile photo
Ryan Partridge's profile photo
Chris Visagie's profile photo
Ryan Peterson's profile photo
Tycko Franklin's profile photo
Mark Wheeler's profile photo
Adrian Alexandru's profile photo
Carsten Ritter's profile photo
Jinath Premaratne's profile photo
Education
  • Stanford University
    Physics, 2000 - 2004
  • University of California, Santa Cruz
    Physics, 2004 - 2008
Links
Contributor to
Work
Occupation
Scientist
Employment
  • California Institute of Technology
    Staff Scientist, 2012 - present
    I'm a principle mission scientist on a NASA Small Explorer mission, the Nuclear Spectroscopic Telescope ARray (NuSTAR), the world's first focusing hard X-ray telescope. I "do science" (I mostly study supernova remnants like Cassiopeia A) now that NuSTAR is up in space, but I also help to develop and maintain the software down here on the ground that turns the bits and bytes coming down from NuSTAR into pictures and spectra.
  • California Institute of Technology
    Postdoc, 2008 - 2012
  • University of California, Santa Cruz
    Research Assistant, 2004 - 2008
Basic Information
Gender
Male
Relationship
Married
Brian Grefenstette's +1's are the things they like, agree with, or want to recommend.
Where to hang out at Google+, list of hangouts at Google+
gphangouts.com

List of the latest hangouts at Google+ (GooglePlus). Visit them, or announce and schedule your own hangout.

9 Reasons to Switch from Facebook to Google+
www.pcworld.com

Can Google+ steal users from Facebook? Yep. There are good reasons to switch from Facebook to Google+, ranging from ease-of-use to respect f

Group/as - Social network user grouping made easy.
group.as

Easily add users of the most popular social networks to groups. Help people know who to follow!

Simple Google+ Bookmarklet by AJ Batac
ajbatac.com

Simple Google+ Bookmarklet. Drag the link below to your toolbar: Share to Google+. Works on Firefox and Google Chrome. By: AJ Batac. Quantca

The IDL Astronomy User's Library
idlastro.gsfc.nasa.gov

IDL Astronomy Library: a collection of low-level routines, mainly related to astronomy, written in the commercial language IDL

Welcome to Google Docs
docs.google.com

Create and share your work online and access your documents from anywhere. Manage documents, spreadsheets, presentations, surveys, and more

Beachwood BBQ: HopCam
www.beachwoodbbq.com

HopCam Click To Expand HopCam Click To Expand.

YouTube - NASA | Massive Solar Eruption Close-up
www.youtube.com

Create AccountSign In. Home. BrowseMoviesUpload. Hey there, this is not a commercial interruption. You're using an outdated browser, whi

YouTube - Taming Infinity
www.youtube.com

Create AccountSign In. Home. BrowseMoviesUpload. Hey there, this is not a commercial interruption. You're using an outdated browser, whi

Do you think Congress should fully fund the James Webb Space Telescope, ...
gopollgo.com

The best free online polling website for Twitter. Create and share polls and votes with your friends and followers.

Google+: The Complete Guide
mashable.com

This guide has everything you'll ever want to know about Google+. Updated regularly.

Google+ Search
gplussearch.com

Search. Search Public Google+ Content. Everything | Posts Only. Everything | Posts Only. For helpful Google+ tips and information about the