Category Archives: Cool Stuff

Black hole Temperature Swings

 

Artist concept: ESA

From NASA:

For the first time, scientists have measured rapidly varying temperatures in hot gas emanating from around a black hole. These ultrafast “winds” are created by disks of matter surrounding black holes.

The winds, according to new measurements of a nearby supermassive black hole obtained with NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) telescope, can heat up and cool down in the span of just a few hours. The black hole is located in the active galaxy IRAS 13224-3809 in the constellation Centaurus. Scientists report these findings, using data from NuSTAR and European Space Agency’s XMM-Newton telescope, in the journal Nature.

“We know that supermassive black holes affect the environment of their host galaxies, and powerful winds arising from near the black hole may be one means for them to do so,” says NuSTAR Principal Investigator Fiona Harrison, professor at Caltech in Pasadena. “The rapid variability, observed for the first time, is providing clues as to how these winds form and how much energy they may carry out into the galaxy.”

Full story from Caltech:

http://www.caltech.edu/news/temperature-swings-black-hole-winds-measured…

AG Carinae

 

Dazzling isn’t it? If the name AG Carinae rings a bell, it could be because of this famous star: Eta Carinae.

Thanks to: ESA/Hubble & NASA

ESA’s caption:

This luminous star, AG Carinae, is losing mass at a phenomenal rate. Its powerful winds reach up to seven million km/hour, and exert enormous pressure on the clouds of material already expelled by the star.

These incredible winds have already cleared a region immediately around the star, and sculpted the material further away into the pattern observed in this Hubble Space Telescope image.

AG Carinae is a rare breed of Luminous Blue Variable star that evolved from a star around 50 times the mass of our Sun. They show variable and unpredictable behaviour, experiencing periods of quiescence and outbursts alike. They are also some of the most luminous stars known: tens of thousands to several million times as luminous as the Sun.

It is worth noting that the bright glare at the centre of the image is not the star itself, which is tiny at this scale and hidden within the saturated region. The white cross is also not an astronomical phenomenon but rather an effect of the telescope.

AG Carinae lies 20 000 light-years away in the constellation of Carina. The image was taken with the Hubble’s Wide Field and Planetary Camera 2, and was first released in September 2014.

Hubble Used to Update Hubble Constant

Pretty cool.  The Hubble  Space Telescope have made an independent measurement of how fast the Universe is expanding. The newly measured expansion rate for the local Universe is very consistent with earlier findings.

Credits: NASA, ESA, Suyu (Max Planck Institute for Astrophysics), Auger (University of Cambridge)

Did I say there was cosmic (gravitational) lensing involved?  Here’s what NASA  has to say:

This research was presented in a series of papers to appear in the Monthly Notices of the Royal Astronomical Society.

The new measurement is completely independent of — but in excellent agreement with — other measurements of the Hubble constant in the local Universe that used Cepheid variable stars and supernovae as points of reference [heic1611].

However, the value measured by Suyu and her team, as well as those measured using Cepheids and supernovae, are different from the measurement made by the ESA Planck satellite. But there is an important distinction — Planck measured the Hubble constant for the early Universe by observing the cosmic microwave background.

While the value for the Hubble constant determined by Planck fits with our current understanding of the cosmos, the values obtained by the different groups of astronomers for the local Universe are in disagreement with our accepted theoretical model of the Universe. “The expansion rate of the Universe is now starting to be measured in different ways with such high precision that actual discrepancies may possibly point towards new physics beyond our current knowledge of the Universe,” elaborates Suyu.

The targets of the study were massive galaxies positioned between Earth and very distant quasars — incredibly luminous galaxy cores. The light from the more distant quasars is bent around the huge masses of the galaxies as a result of strong gravitational lensing. This creates multiple images of the background quasar, some smeared into extended arcs.

Because galaxies do not create perfectly spherical distortions in the fabric of space and the lensing galaxies and quasars are not perfectly aligned, the light from the different images of the background quasar follows paths which have slightly different lengths. Since the brightness of quasars changes over time, astronomers can see the different images flicker at different times, the delays between them depending on the lengths of the paths the light has taken. These delays are directly related to the value of the Hubble constant. “Our method is the most simple and direct way to measure the Hubble constant as it only uses geometry and General Relativity, no other assumptions,” explains co-lead Frédéric Courbin from the Laboratory of Astrophysics, Lastro (EPFL), Switzerland.

Using the accurate measurements of the time delays between the multiple images, as well as computer models, has allowed the team to determine the Hubble constant to an impressively high precision: 3.8 percent. “An accurate measurement of the Hubble constant is one of the most sought-after prizes in cosmological research today,” highlights team member Vivien Bonvin, from EPFL, Switzerland. And Suyu adds: “The Hubble constant is crucial for modern astronomy as it can help to confirm or refute whether our picture of the Universe — composed of dark energy, dark matter and normal matter — is actually correct, or if we are missing something fundamental.”

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

GOES 16

This view of the Earth and Moon comes from the American weather satellite GOES-16. This image comes from the Advanced Baseline Imager (ABI) instrument, built by Harris Corporation and can provide an image every 15 minutes.

The (US) National Oceanic and Atmospheric Administration (NOAA) satellite will have company soon as the GOES-17 is in the works.

The NOAA press release – with more images, is located here.

Credit: NOAA

A Bakers Dozen

Wow,very exciting! Congratulations to Einstein@home! The Astrophysical Journal presents 13 of 17 newly discovered pulsars found with the distributed computing project.

“Einstein@Home searched through 118 unidentified pulsar-like sources from the Fermi-LAT Catalog,” says Prof. Dr. Bruce Allen, director of Einstein@Home and director at the Max Planck Institute for Gravitational Physics in Hanover. “Colin has shown that 17 of these are indeed pulsars, and I would bet that many of the remaining 101 are also pulsars, but in binary systems, where we lack sensitivity. In the future, using improved methods, Einstein@Home is going to chase after those as well, and I am optimistic that we will find at least some of them.”

See the entire press release from Einsteinathome.org

I’ve always been a fan of these distributed projects I participated in the SETI project for a long time and now am involved with a couple of the projects at Zooniverse.

Graphic: Einstein@home

Looking At Home

A beautiful sight and one that could be seen by humans in the not too distant future.  This image was taken from the Mars Reconnaissance Orbiter and took a bit of processing, however I suspect at some point in a voyage to Mars the travelers would see this very sight.

I wonder if looking back at this from a craft heading to Mars, if second thoughts come to mind.

earthmoon

About the image from NASA

This composite image of Earth and its moon, as seen from Mars, combines the best Earth image with the best moon image from four sets of images acquired on Nov. 20, 2016, by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter.

Each was separately processed prior to combining them so that the moon is bright enough to see. The moon is much darker than Earth and would barely be visible at the same brightness scale as Earth. The combined view retains the correct sizes and positions of the two bodies relative to each other.

HiRISE takes images in three wavelength bands: infrared, red, and blue-green. These are displayed here as red, green, and blue, respectively. This is similar to Landsat images in which vegetation appears red. The reddish feature in the middle of the Earth image is Australia. Southeast Asia appears as the reddish area (due to vegetation) near the top; Antarctica is the bright blob at bottom-left. Other bright areas are clouds.

These images were acquired for calibration of HiRISE data, since the spectral reflectance of the Moon’s near side is very well known. When the component images were taken, Mars was about 127 million miles (205 million kilometers) from Earth. A previous HiRISE image of Earth and the moon is online at PIA10244.

Credit: NASA/JPL-Caltech/Univ. of Arizona

Edit: the could – well debacle was fixed, tried to get “fancy” – fail lol.

Psyche

Psyche: Journey to a Metal World from School of Earth & Space on Vimeo.

Psyche is a mission proposed by Arizona State University. It is named after 16 Psyche a very interesting minor planet in the asteroid belt.

Arizona State University (School of Earth and Space Exploration) has a very nice web-page outlining the mission and the asteroid – well worth the visit.

The big news is that Psyche HAS been selected as one of the two Discovery missions. The probable launch date is in 2023. Congratulations to ASU!

The other mission is called appropriately named Lucy and it involves what are called fossils of planetary formation, namely Trojan asteroids in Jupiter’s orbit.

Lucy Mission (pdf file).

The NASA announcement about the two missions with very good descriptions of both.

The 2016 Time Adjustment

I wonder if when the new year rang in if the countdown included the extra second that was added to the world clocks. Probably not and while it might not seem like much,  the time change is important to our view of the world thanks to our modern technology even if we don’t realize it.

We have added 27  “leap-seconds” to the clock since the practice started in 1972. Read more about adding leap-seconds.

sdojan1

From (mostly) NASA:   On Dec. 31, 2016, official clocks around the world added a leap second just before midnight Coordinated Universal Time — which corresponds to 6:59:59 p.m. EST. NASA missions also had to make the switch, including the Solar Dynamics Observatory, or SDO, which watches the sun 24/7.

Clocks do this to keep in sync with Earth’s rotation, which gradually slows down over time. When the dinosaurs roamed Earth, for example, our globe took only 23 hours to make a complete rotation. In space, millisecond accuracy is crucial to understanding how satellites orbit.

“SDO moves about 1.9 miles every second,” said Dean Pesnell, the project scientist for SDO at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “So does every other object in orbit near SDO. We all have to use the same time to make sure our collision avoidance programs are accurate. So we all add a leap second to the end of 2016, delaying 2017 by one second.”

The leap second is also key to making sure that SDO is in sync with the Coordinated Universal Time, or UTC, used to label each of its images. SDO has a clock that counts the number of seconds since the beginning of the mission. To convert that count to UTC requires knowing just how many leap seconds have been added to Earth-bound clocks since the mission started. When the spacecraft wants to provide a time in UTC, it calls a software module that takes into consideration both the mission’s second count and the number of leap seconds — and then returns a time in UTC.

Credit: NASA/SDO