Skrifennow: April 2019

Saturday 13 April 2019

Ebrenn y'n nos mis-Ebrel 2019

Here is the transcript for the Ebrenn y'n Nos segment for April 2019 for Radyo an Gernewegva, broadcast in #427:

Termyn a wra neyja yn sur ha gwaynten yw, hag yma mis-Ebrel ow talleth.
Nyns yw an nosow mar hir lemmyn, mes hwath yma taklow dhe weles.
Loor nowydh yw orth 5ves mis-Ebrel, an kynsa kwartron an 12ves, loor leun dhe’n 19ves ha’n diwettha kwartron 26ves, ha’n loor nowydh arta dhe’n 4a mis-Me. Meurth yw hwath gweladow yn gorthugher y’n ranneves Taurus, mes pell yw diworth a’n norvys yn y resegva, ha ny via meur gwelys a’n enep yn pellwelell. Yow ha Sadorn yw gweladow yn ebrenn kyns an bora, isel y’n soth-est.

Yma kowas sterennow kodha an Lyrids an mis-ma. An gwella termyn dh’aga gweles yw 22a - 23a mis-Ebrel. Y fydh ogas hag 20 a sterennow kodha pub our ow mos dhyworth an ranneves Lyra, yn north-est an ebrenn.

Imaj: NASA solarsystem.nasa.gov/asteroids-comets-and-meteors/meteors-and-meteorites/lyrids/in-depth

Yma nowodhow drog diworth Meurth. Opportunity yw kellys. Soweth ny sewenis an ragdres dhe gestava orth an wandryell arta wosa an tewedh doust mis-Metheven warlyna.
mars.nasa.gov/news/8413/nasas-opportunity-rover-mission-on-mars-comes-to-end

An wandryell ma o sewen bras yn gwiryonedh, drefenn an ragres derowel o saw dhe dhurya 90 dydh ha viajya 1000 meter. Hi a dhuryas 14 bloedh, ha viajya moy ages 45km. www.jpl.nasa.gov/news/news.php?release=2014-245

www.planetary.org/multimedia/space-images/small-bodies/cometary-nuclei-to-scale.html

http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20190208
Pyth yw ‘bi-lobed contact binary’ yn Kernewek? Planetik dewek kestavek gans dew lapp? Nag yw rond an dhew lapp mes hirbelyek ha plattys yns.
Moy leven yw y enep es po Bennu po Ryugu, yth yw taklenn a’n sort steren lostek na wrussa dos nes dhe’n howl. Yth esa Ultima Thule formys hag y dhew lapp keskwattya yn lent hag yn medhel, hag yth i a wrug glena warbarth.

Bys nessa prys,
Davydh Trethewey

Sunday 7 April 2019

An gwrandryell gwyls

Yth esen vy gwrandryell dres lies bledhen
My re wrug ow batris fest gwaghes yn tien
My re wrug dehweles data termyn hir
Mes ny wrav vy rosya namoy dres an tir

Imaj: www.jpl.nasa.gov

Nag eus nerth vyth genev
Ny wrug howlsplann bos krev
Lowr dhe dhaskarga'n batris
Ha sinella'n norvys

Yth ethen dhe gowdoll a wren vy a-rag
Leveris orth NASA ow rosow o stag
Yn mysk an tewennow ow sedhi ens i
Mes my a wrug rydhhe ow rosow gans bri

mars.nasa.gov/resources/5874/opportunitys-rub-al-khali-panorama

Nag eus nerth vyth genev
Ny wrug howlsplann bos krev
Lowr dhe dhaskarga'n batris
Ha sinella'n norvys

Yth esa an doust war ow fanellys howl
Martesen yth esa an diwedh ow thowl
Hag arta an gwyns a wrug aga glanhe
Nerth o gans ow batris pan hwrug howl krevhe

mars.nasa.gov/news/8420/opportunitys-parting-shot-was-a-beautiful-panorama

Nag eus nerth vyth genev
Ny wrug howlsplann bos krev
Lowr dhe dhaskarga'n batris
Ha sinella'n norvys

Soweth yth esa hi ow kul tewedh
Doust a-dro Meurth ny wren vy godhvos bythkweth
An tewlder a dhuryas an nos hag an jydh
Ow fanellys howl ny wrug ri dhymm nerth vyth

Nag eus nerth vyth genev
Ny wrug howlsplann bos krev
Lowr dhe dhaskarga'n batris
Ha sinella'n norvys

mars.nasa.gov/resources/5617/opportunity-catches-its-shadow

Monday 1 April 2019

New research show elephants first created Cornwall's road network

Researchers at the University of North Cornwall are working on a new project indicating that much of Cornwall's road network was created by elephants trampling the native vegetation.

Elephants lived in the British Isles, including Cornwall during the Ipswichian interglacial (also known as Eemian) epoch between 130,000 years ago and 115,000 years ago, when temperatures were similar to or slightly warmer than at present, before the last glacial period.

See the following link by George Monbiot: www.monbiot.com/2015/06/15/thinking-like-an-elephant/

Historical average temperature on Earth (Wikimedia Commons)

A model of a straight-tusked elephant (Palaeoloxodon antiquus) (Credit: BBC Earth/Apotea)

Elephants will have made tracks over most of Britain, however in much of this area, the tracks would surely have been erased by ice sheets in the Last Glacial Maximum.

Ice sheets in Europe during the Last Glacial Maximum

Cornwall however was not glaciated, so tracks made by elephants in the 130-115kyr BP interglacial could have survived, and may have continued in use by herds of migrating woolly mammoth that visited Cornwall in the summer to graze, and potentially the early Cornish who hunted them.

Woolly mammoth were able to reach their summer pastures in Cornwall by crossing the Channel river - either in sections where it was broad and shallow, or during the spring before the ice melted.

Elephants travelling on their favourite routes in Cornwall would over time create enduring tracks by trampling and browsing of vegetation, and compaction of soil. These routes would be more easily followed by other wildlife, and eventually humans. There would also have been additional resources due to the distribution of plant seeds and improvement of soil nutrients by elephant droppings.

The research used a download of the secondary, tertiary and unclassified road network in Cornwall, from OpenStreetMap. Primary and trunk roads were ignored since they are liable to be on modern alignments.

Were some of these roads built by elephants?

Cornwall was contrasted with Cumbria, since any elephant tracks would be expected to be erased there during the last glacial period.

Cumbria in northern England was covered in thick ice sheets during the last glacial period, so it is presumed that any traces of elephants from the previous interglacial are erased.

Northern Wales was similarly covered by a thick ice sheet.

Modelling of the last glacial period in Wales (Patton et al 2012) researchgate.net/publication/248381136_The_last_Welsh_Ice_Cap_Part_1_-_Modelling_its_evolution_sensitivity_and_associated_climate.

The secondary, tertiary and unclassified roads have various numbers of features in the different areas:

Cornwall - 9730
Cumbria - 9704
Wales - 30775

Using K-means clustering, showing 5 clusters in Cornwall and Cumbria:

there are the Isles of Scilly, and a spurious feature off the map, so there are really 7 clusters here

5 K-means clusters of the minor road network in Cumbria

The numbers of features, total road length, mean and median length in the clusters are:

Cornwall:

0: 1001, 846km, 845m, 455m
3: 2689, 1406km, 523m, 257m
4: 2034, 1375km, 676m, 403m
5: 2597, 1597km, 615m, 293m
6: 1308, 596km, 456m, 215m

Cumbria:

0: 2104, 1202km, 571m, 232m
1: 1754, 802km, 457m, 213m
2: 2468, 1929km, 782m, 344m
3: 1793, 861km, 480m, 213m
4: 1585, 914km, 576m, 241m

Cornwall has 2 clusters (0 and 6 in the far west, and north Cornwall respectively) that are much smaller in terms of number of features than the other 3, indicating that certain clusters, notably the two largest clusters, labelled 3 and 5 have a dense road network which originated when elephants followed river valleys in their migrations in search of food sources.
Cluster 0 in North Cornwall is less dense possibly due to episodic glaciation of Bodmin Moor and surrounding areas erasing elephant tracks.

Cumbria in contrast has relatively evenly sized clusters, apart from cluster 2 which is larger than the rest, correlated with a flatter topography than the rest of the area.
The remaining clusters are similar in number of features and average line length. This is to be expected due to the erasure of the pre-glacial elephant migration routes.

Heatmap of road intersections (10km kernel size)

In Cornwall, there is a strong variation in the regional distribution of road junction density due to differences in the density of the elephant migration routes. It may be supposed that the area between Truro, Redruth and Penryn was highly favourable to elephants during the 130-115kyr BP interglacial.

In Cumbria, there is a lower density of road intersections due to the erasure of previous interglacial elephant migration tracks during the last glacial period.

The secondary, tertiary and unclassified road network in Wales, in 15 clusters to keep the average number of features broadly comparable to the previous work.

Outside the major urban areas, the density of the road junctions are markedly lower in Wales than in Cornwall, indicating elephant tracks were erased in the last glacial maximum.

Conclusion
The relative high density of the Cornish minor road network is shown in this work to originate in tracks created by elephants in the 130-115 kyr BP interglacial, and potentially maintained through the glacial period by seasonally migrant wooly mammoth grazing the tundra vegetation available in Cornwall in the summer during the glacial period. In contrast, in areas that were glaciated including Wales and Cumbria the elephant tracks were erased, resulting in a different road network topology.

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