Where do cosmic rays come from?

The Royal High School, Bath

Image (Courtesy of the Hubble Space Telescope): HST Mystic Mountain, Carina Nebula.

The correlation between the number of cosmic ray events and Right Ascension.

Celestial Measures of Location

A mapping system for the night sky. Right Ascension:

• Longitude measured along the celestial equator. • Measured eastward from the vernal equinox.• Expressed in hours, minutes and seconds.

Declination:• Latitude for the night sky.• Measured from the celestial equator.• Expressed in degrees.

Zenith:The imaginary point located directly above a particular location.

Graph: Percentage Change from the Mean No. Events by Right Ascension

Graph Observations

Stations with almost complete sets of data chosen.• Reduces possibility of variation.• Eliminates seasonal effects.• Multiple sources improve reliability

and validity of conclusion.

Observations:• Pattern found within data sets of 5

detectors.• Highest +ve change at 18h RA.• Lowest –ve change at 6h RA.• Only station 7001 around mean.

0022 Amsterdam; St Ignatius Gymnasium

0305 Kennemerland; Gemeentehuis Castricum

1003 Utrecht; Museum Sterrenwacht Sonnenborogh

3102 Zwijndrecht; Walburg College (Hendrik Ido Ambacht)

7001 Enschede; Universiteit Twente 1

8201 Panningen; Bouwens van der Boije College

Sky Map

Possible areas consisting of supernovae (dying stars) around 51.5° declination (facing direction in night sky in Bath) and 18hrs RA.

Non-conclusive evidence of sources.

www.sky-map.org

Graph: Percentage Change from the Mean No. Events by Right Ascension

0hrs RA;Spring Equinox

12hrs RA;Autumn Equinox

18hrs RA;Winter Solstice

6hrs RA;Summer Solstice

Position of the Earth in Orbit

Graph: Percentage Change from the Mean No. Events by Right Ascension

What do we already know?

Majority of cosmic radiation received by detectors are from the zenith (51.5° declination).• At zenith, least obstruction from the atmosphere for cosmic rays to

travel through.

Summer:• Sun rises closer to the zenith.• More daylight hours.

Winter:• Sun rises further away from zenith.• Shorter daylight hours.

51.5° N

Graph: Percentage Change from the Mean No. Events by Right Ascension

Our Hypothesis?

The Sun may have a blocking effect on cosmic radiation from beyond the Solar System.

Supporting Evidence

Mean Average of Hourly Data (RHS Data)

Supporting Evidence

Mean Average of Hourly Data (RHS Data)

For both graphs, the no. cosmic ray events detected are at a minimum at noon.• At noon, the sun is nearer to the zenith and

within range of the detectors.

Confidence intervals to show ranges of uncertainty in data values.• Range of values of y-axis is small; higher chance

of error.

RHS: Trend is present with 95% confidence.

Station 305:• Trend is also present, but 99% confidence

means this trend is more reliable.• Also shows that minimum observed at noon

is likely to be a real effect.

Mean Average of Hourly Data for 2013

RHS

Station 305

?

Outside Research

Philosophical Transactions of the Royal Society of London. Series 1, Mathematical and Physical Sciences © 1975 The Royal Society.• ‘…the basic cosmic ray sources in galactic models are supernova explosions and

particularly cosmic ray acceleration by pulsars arising from these explosions.

American Association for the Advancement of Science (AAAS);‘Science: Evidence Shows That Cosmic Rays Come From Exploring Stars’ (13 February 2013).• ‘Data collected by the Fermi Space Telescope provide conclusive evidence that supernovae are

the source’ of cosmic rays… ‘general consensus among scientists that supernova remnants (the leftovers of a supernova explosion) are the sources of cosmic rays.’

Science Magazine; Issue 25 November 2011: Vol. 334.• ‘[A group of researchers led by M. Ackermann] report observations with NASA's Fermi Large Area

Telescope that are directly related to the origin of cosmic rays. They identified

distributed emission of gamma-rays over the energy range of 1 to 100 GeV in the Cygnus X region of the sky with a “cocoon” of freshly accelerated cosmic rays.’

What can we say about what we already know?

If the sun is nearer to the zenith, then it is likely to be within range of the detectors.

In the summer, we experience more hours of daylight. Thus, the sun is within the range of the detectors for a greater length of time.

If this is so, then the sun would be obstructing more cosmic radiation from being detected.

This means that in the summer, the sun causes less events to be detected.

Conclusions

The sun may be a primary obstruction in the detection of cosmic radiation.

However, the sources of cosmic radiation detected by stations in the Netherlands may be found within areas of the Universe, in the

range of51 – 52° declination and 17 – 19 hours Right Ascension.

Images are featured in this presentation in courtesy ofWikipedia, Google Images, Sky-Map.org and the Hubble Space Telescope.