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Hopeless at maths



 
 
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  #22  
Old March 31st 17, 11:27 AM posted to uk.tech.digital-tv
Brian Gaff
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Posts: 6,879
Default Hopeless at maths

Yes I don't understand where the distance to London comes in in the first
place. this makes it a double problem when it really only needs to be a one
stage one.
Brian

--
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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
wrote in message
...
On Thu, 30 Mar 2017 21:40:31 -0000 (UTC), Tim+
wrote:

Bill Wright wrote:
I'm hopeless at maths, but I'm trying to get something across to an
intelligent child. So, if the distance from here to London (250km) is
represented by the thickness of a hair (0.2mm) h


Why use hair widths as an analogy? Most of us have no idea how thick a
hair
is. Surely the standard unit of length/distance is the double decker bus?
;-)

Now your are just splitting hairs.

G.Harman



  #23  
Old March 31st 17, 11:44 AM posted to uk.tech.digital-tv
pinnerite
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Posts: 92
Default Hopeless at maths

Chris Green wrote:

Mark Carver wrote:

Bugger. So he did. Anyway I thought the SI units for comparative scale
were football pitches, London buses, or Olympic sized swimming pools ?

Exactly! :-)

.... silly analogies 'r us.


Readers of the New Scientist will understand.

--
Mageia 5.1 for x86_64, Kernel:4.4.39-desktop-2.mga5
KDE version 4.14.5 on an AMD Phenom II X4 Black edition.

  #24  
Old March 31st 17, 11:58 AM posted to uk.tech.digital-tv
R. Mark Clayton[_2_]
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Posts: 530
Default Hopeless at maths

On Thursday, 30 March 2017 20:08:54 UTC+1, Roger Mills wrote:
On 30/03/2017 19:39, Bill Wright wrote:
I'm hopeless at maths, but I'm trying to get something across to an
intelligent child. So, if the distance from here to London (250km) is
represented by the thickness of a hair (0.2mm) how far is a light year?
It doesn't have to be a hair; it could be anything familiar and small.

It's 2.5 million light years to the Andromeda Galaxy; that's what we're
discussing.

Help!

Bill


Do you have any familiar small objects that are only about 7,000 Km in
size?


Er the earth? Radius about 6k4m or nearly 8,000 miles in diameter.

'Cos, according to my back of an envelope calculations, that's the
size you'd need to represent a light year if 250Km is represented by 0.2mm
--
Cheers,
Roger
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  #25  
Old March 31st 17, 02:04 PM posted to uk.tech.digital-tv
Roger Mills[_2_]
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Posts: 273
Default Hopeless at maths

On 31/03/2017 11:58, R. Mark Clayton wrote:
On Thursday, 30 March 2017 20:08:54 UTC+1, Roger Mills wrote:
On 30/03/2017 19:39, Bill Wright wrote:
I'm hopeless at maths, but I'm trying to get something across to an
intelligent child. So, if the distance from here to London (250km) is
represented by the thickness of a hair (0.2mm) how far is a light year?
It doesn't have to be a hair; it could be anything familiar and small.

It's 2.5 million light years to the Andromeda Galaxy; that's what we're
discussing.

Help!

Bill


Do you have any familiar small objects that are only about 7,000 Km in
size?


Er the earth? Radius about 6k4m or nearly 8,000 miles in diameter.


Except that Bill said it had to be familiar and SMALL. I know that size
is relative and all that - but I doubt that Bill would consider the
earth to be small.

Problem is that there aren't any answers which meet his criteria!
--
Cheers,
Roger
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  #26  
Old March 31st 17, 05:31 PM posted to uk.tech.digital-tv
Brian Gaff
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Posts: 6,879
Default Hopeless at maths

You know after reading the item below I sort of wondered whether the object
discussed was actually travelling toward us at a significant proportion of
the speed of light, making it seem to have higher energy radiation...
https://www.jpl.nasa.gov/news/news.php?feature=6789

Andromeda's Bright X-Ray Mystery Solved by NuSTAR
Jet Propulsion Laboratory
March 23, 2017

The Milky Way's closest neighbor, Andromeda, features a dominant source
of high-energy X-ray emission, but its identity was mysterious until now.
As reported in a new study, NASA's NuSTAR (Nuclear Spectroscopic Telescope
Array) mission has pinpointed an object responsible for this high-energy
radiation.

The object, called Swift J0042.6+4112, is a possible pulsar, the dense
remnant of a dead star that is highly magnetized and spinning, researchers
say. This interpretation is based on its emission in high-energy X-rays,
which NuSTAR is uniquely capable of measuring. The object's spectrum is
very similar to known pulsars in the Milky Way.

It is likely in a binary system, in which material from a stellar companion
gets pulled onto the pulsar, spewing high-energy radiation as the material
heats up.

"We didn't know what it was until we looked at it with NuSTAR," said Mihoko
Yukita, lead author of a study about the object, based at Johns Hopkins
University in Baltimore. The study is published in The Astrophysical
Journal.

This candidate pulsar is shown as a blue dot in a NuSTAR X-ray image of
Andromeda (also called M31), where the color blue is chosen to represent
the highest-energy X-rays. It appears brighter in high-energy X-rays than
anything else in the galaxy.

The study brings together many different observations of the object from
various spacecraft. In 2013, NASA's Swift satellite reported it as a
high-energy
source, but its classification was unknown, as there are many objects
emitting low energy X-rays in the region. The lower-energy X-ray emission
from the object turns out to be a source first identified in the 1970s
by NASA's Einstein Observatory. Other spacecraft, such as NASA's Chandra
X-ray Observatory and ESA's XMM-Newton had also detected it. However,
it wasn't until the new study by NuSTAR, aided by supporting Swift satellite
data, that researchers realized it was the same object as this likely
pulsar that dominates the high energy X-ray light of Andromeda.

Traditionally, astronomers have thought that actively feeding black holes,
which are more massive than pulsars, usually dominate the high-energy
X-ray light in galaxies. As gas spirals closer and closer to the black
hole in a structure called an accretion disk, this material gets heated
to extremely high temperatures and gives off high-energy radiation. This
pulsar, which has a lower mass than any of Andromeda's black holes, is
brighter at high energies than the galaxy's entire black hole population.

Even the supermassive black hole in the center of Andromeda does not have
significant high-energy X-ray emission associated with it. It is unexpected
that a single pulsar would instead be dominating the galaxy in high-energy
X-ray light.

"NuSTAR has made us realize the general importance of pulsar systems as
X-ray-emitting components of galaxies, and the possibility that the high
energy X-ray light of Andromeda is dominated by a single pulsar system
only adds to this emerging picture," said Ann Hornschemeier, co-author
of the study and based at NASA's Goddard Space Flight Center, Greenbelt,
Maryland.

Andromeda is a spiral galaxy slightly larger than the Milky Way. It resides
2.5 million light-years from our own galaxy, which is considered very
close, given the broader scale of the universe. Stargazers can see Andromeda
without a telescope on dark, clear nights.

"Since we can't get outside our galaxy and study it in an unbiased way,
Andromeda is the closest thing we have to looking in a mirror,"
Hornschemeier
said.

NuSTAR is a Small Explorer mission led by Caltech and managed by JPL for
NASA's Science Mission Directorate in Washington. NuSTAR was developed
in partnership with the Danish Technical University and the Italian Space
Agency (ASI). The spacecraft was built by Orbital Sciences Corp., Dulles,
Virginia. NuSTAR's mission operations center is at UC Berkeley, and the
official data archive is at NASA's High Energy Astrophysics Science Archive
Research Center. ASI provides the mission's ground station and a mirror
archive. JPL is managed by Caltech for NASA.

For more information on NuSTAR, visit:

http://www.nasa.gov/nustar

http://www.nustar.caltech.edu

News Media Contact
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425


2017-083

--
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This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Bill Wright" wrote in message
news
I'm hopeless at maths, but I'm trying to get something across to an
intelligent child. So, if the distance from here to London (250km) is
represented by the thickness of a hair (0.2mm) how far is a light year?
It doesn't have to be a hair; it could be anything familiar and small.

It's 2.5 million light years to the Andromeda Galaxy; that's what we're
discussing.

Help!

Bill



  #27  
Old March 31st 17, 06:05 PM posted to uk.tech.digital-tv
Johnny B Good[_2_]
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Posts: 436
Default Hopeless at maths

On Fri, 31 Mar 2017 09:49:34 +0000, David wrote:

On Fri, 31 Mar 2017 07:26:05 +0100, Mark Carver wrote:

On 30/03/2017 20:53, Paul Ratcliffe wrote:
On Thu, 30 Mar 2017 20:00:32 +0100, Mark Carver

wrote:

So in 2.5 years

2.3635637 x 10^16 metres

2.3635637 x 10^13 km

So 2.3635637 x 10^13 km / 250 x 10^3 = 9.4542548 x 10^7

Yeah, but he said 2.5 million light years, so multiply that by 10^6.


Bugger. So he did. Anyway I thought the SI units for comparative scale
were football pitches, London buses, or Olympic sized swimming pools ?


Perhaps this can help?

https://www.theregister.co.uk/Design/page/reg-standards-converter.html

You might have thought so but I can't really see how. BTW, I was rather
intrigued by the "maximum velocity of a sheep in a vacuum" 'standard' so
tried some test values like 1 mps followed by 186000mps then 3000 Kps
followed by 3999 then 3998 before getting a value of 100%. I knew the
186000mps figure was more approximately the speed of light than the
300000Kps (or 3 x 10^8 m/s) figure given for C which I initially
suspected to be maximum velocity of a sheep in a vacuum before figuring
out that it's a synonym for C/100. I'm assuming this isn't purely an
invention of El Reg...

... apropos of which, there seems to be a dichotomy between the
PhysicsForums article on the subject of "maximum velocity of a sheep in a
vacuum" here https://www.physicsforums.com/thread...y-of-sheep-in-
a-vacuum.303365/ where they state:

"The Vulture Central standard velocity for a sheep in a vacuum is,
therefore, c/(50+0), or 5,995 km/sec."

which is twice that given by the calculator on the register page itself.

As for Bill's original problem, that of giving an intelligent child some
measure or appreciation of the vast distances involved in intergalactic
space, it does rather depend on whether or not said child has grasped the
basic concept of a counting system that uses positional notation and the
limitless power this gives us to express any quantity, including the
rapidly shrinking number of nanometres that seperate us from our
neighbouring Galaxy.

He could hardly do worse than point said child to the "Hitch Hikers'
Guide to The Galaxy", in particular, section on "Space". :-)

--
Johnny B Good
  #28  
Old March 31st 17, 06:31 PM posted to uk.tech.digital-tv
R. Mark Clayton[_2_]
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Posts: 530
Default Hopeless at maths

On Friday, 31 March 2017 14:03:17 UTC+1, Roger Mills wrote:
On 31/03/2017 11:58, R. Mark Clayton wrote:
On Thursday, 30 March 2017 20:08:54 UTC+1, Roger Mills wrote:
On 30/03/2017 19:39, Bill Wright wrote:
I'm hopeless at maths, but I'm trying to get something across to an
intelligent child. So, if the distance from here to London (250km) is
represented by the thickness of a hair (0.2mm) how far is a light year?
It doesn't have to be a hair; it could be anything familiar and small.

It's 2.5 million light years to the Andromeda Galaxy; that's what we're
discussing.

Help!

Bill

Do you have any familiar small objects that are only about 7,000 Km in
size?


Er the earth? Radius about 6k4m or nearly 8,000 miles in diameter.


Except that Bill said it had to be familiar and SMALL. I know that size
is relative and all that - but I doubt that Bill would consider the
earth to be small.


Well it is very small compared to the sun, solar system, milky way or the universe!


Problem is that there aren't any answers which meet his criteria!
--
Cheers,
Roger
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  #29  
Old April 1st 17, 12:43 PM posted to uk.tech.digital-tv
Paul Ratcliffe
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Posts: 2,465
Default Hopeless at maths

On Fri, 31 Mar 2017 10:31:22 -0700 (PDT), R. Mark Clayton
wrote:

Except that Bill said it had to be familiar and SMALL. I know that size
is relative and all that - but I doubt that Bill would consider the
earth to be small.


Well it is very small compared to the sun, solar system, milky way or the universe!


Has anybody got a small piece of fairy cake?
 




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