The Rosetta probe witnessed the awakening of the icy comet
Professors Esa Kallio from Aalto University and Hannu Koskinen from the University of Helsinki have been analysing the Rosetta probe’s measurements of the comet 67P/Churyumov-Gerasimenko since August 2014. The first water vapour jets from the comet were observed in September 2014, i.e. very early in the comet’s awakening stage. The findings surprised the researchers.
- We were really surprised that the water vapour from the comet was able to disrupt the solar wind significantly, even though the comet was still a long way from the warmth of the Sun. At the start of the measurements, the comet’s distance from the Sun was more than three times the distance between the Earth and the Sun, explains Professor Esa Kallio.
On the basis of the measurements, the Finnish group was also able to estimate that the comet was losing water at a rate of about one kilogramme a second. Professor’s findings were published on 23rd January in the prestigious Science Magazine.
3-D computer simulation of comet 67P/Churyumov-Gerasimenko's charged particle environment and characteristic tail when encountering the solar wind. Water ions, pictured as a blue-white cloud, are blown away upwards from the nucleus of the comet by the solar wind stream. The solar wind, composed of high-energy particles such as electrons and protons, is represented by coloured arrows, changing from white to red with increasing densities. When the solar wind encounters the comet's atmosphere, it is deflected and slowed down around the nose of the comet. Picture: Markku Alho / Aalto University
The research of Professor Kallio’s group focussed on interpreting the material produced by the spacecraft’s Ion Composition Analyzer (ICA). The ICA particle measurement device is one of five sensors in the Rosetta Plasma Consortium and it measures when the comet starts to produce water vapour jets and the electrically charged light particles they generate. The Finnish Meteorological Institute has participated in building the ICA since the mid-1990s under the direction of research manager Dr. Walter Schmidt.
Understanding through modelling
The spacecraft, which has been placed in the comet’s orbit, has eleven scientific measurement devices which take an array of measurements of the comet's development as it nears the Sun.
As they separate the particles form the comet’s tail, and for the first time it will now be possible to measure its growth from its formation to its decline. The ICA was witnessing the awakening of the icy comet by the Sun and the formation of vapour before Rosetta’s Philae lander was released and transmitted new data about the erosion of the comet’s surface.
- The particles leaving the tail give information about the comet’s space weather i.e. the comet’s environment in space where the heat induced by sunlight and the solar wind together erode the surface of the comet, explains Professor Kallio.
Professor Kallio and his research group analyse the measurements from the spacecraft using a three dimensional computer simulation.
- The modelling we use significantly deepens our understanding of the measurement data we receive. You cannot develop a holistic picture of events on the comet simply by taking measurements at individual locations, nor by using a single measurement instrument. The only way is by analysing and combining measurement results and using them to create a model.
In addition to gas generated from the ice, other material also leaves the comet's surface. Professor Kallio’s research group hopes to get some heavy dust particles to examine later. The next phase of the research work is to compare results with those from other measurement instruments.
- We are focussing particularly on the fluctuations in the intensity of erosion during the lifecycle of the comet. The intensity of erosion is thought to increase as the comet approaches the Sun and is presumed to be at its maximum in August 2015. That is why we expect more vapour jets as the summer approaches.
Professor Esa Kallio, Aalto University
tel. +358 (0)50 4205 857, [email protected]
Professor Hannu Koskinen, University of Helsinki
tel. +358 (0)50 4155 356, [email protected]
Research Manager Dr. Walter Schmidt, Finnish Meteorological Institute
tel. +358 (0)29 539 4658, [email protected]
Link to the magazine: http://www.sciencemag.org/content/347/6220/aaa0571.full
An animation based on modelling by Professor Kallio’s research group and other material can be seen here: http://space.aalto.fi/news/pub-science-2015-01-23.html
Rosetta is the cornerstone programme of the European Space Agency. The Rosetta spacecraft is composed of the orbiter and the Philae lander. The Rosetta orbiter will follow the comet 67P/Churyumov-Gerasimenko at least until the end of 2015. As Rosetta orbits the comet it carries eleven scientific measurement instruments which are continuously providing historical data about the comet and its development. In Finland the Finnish Meteorological Institute participated in the construction of the ICA and Aalto University and the University of Helsinki are working on interpreting the measurement data. The measurements are expected to increase our knowledge of the initial moments of the creation of our solar system when the comets were born. Comets are also interesting because comets colliding with the Earth brought water with them and possibly organic molecules.
"Professor Esa Kallio wa Chuo Kikuu cha Aalto na Profesa Hannu Koskinen wa Chuo Kikuu cha Helsinki wamekuwa wakichunguza vipimo vya ""Rosetta"" vya kometi 67P-Gerasimenko tangu Agosti 2014." Mlipuko wa mvuke wa maji kutoka kwa kometi hiyo uligunduliwa mnamo Septemba 2014. mapema sana katika hatua ya kuamka ya kometi. Matokeo hayo yaliwashangaza watafiti. "Kama tulivyoona hapo awali, mvuke wa maji kutoka kwa kometi hiyo ulisababisha ""mvuke wa jua"" kwa kiasi kikubwa, ingawa kometi hiyo ilikuwa bado mbali na joto la jua." Wakati wa uchunguzi huo, kometi hiyo ilikuwa umbali wa mara tatu zaidi ya umbali kati ya dunia na jua, alisema Profesa Esau Kallio. Kwa kuzingatia vipimo hivyo, kikundi cha Finland kiliweza pia kukadiria kwamba kometi hiyo ilikuwa ikipoteza maji kwa kiwango cha karibu kilo moja kwa sekunde. Utafiti huo ulichapishwa Januari 23 katika jarida la Science. Mfano wa kompyuta ya 3D ya kometi 67P-Gerasimenko na mkia wake wa kawaida wakati wa kukutana na upepo wa jua Ioni za maji, zilizoonyeshwa kama wingu jeupe na la bluu, hupeperushwa juu kutoka kwenye kiini cha kometi na upepo wa jua. Upepo wa jua, unaoundwa na chembechembe zenye nishati nyingi kama vile elektroni na protoni, unawakilishwa na mishale yenye rangi, inayobadilika kutoka nyeupe hadi nyekundu kwa kuongezeka kwa wiani. Upepo wa jua unapokutana na angahewa la kometi, hupotoshwa na kupunguza mwendo wake karibu na pua ya kometi. "Kama ilivyoelezwa katika makala ya kwanza ya jarida la ""Ion Composition Analysis"" ya Chuo Kikuu cha Aalto, utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa utafiti wa ion." Kifaa cha kupima chembechembe cha ICA ni moja ya sensorer tano katika Rosetta Plasma Consortium na hupima wakati kometi inaanza kuzalisha maji mvuke jets na chembechembe nyepesi umeme wao kuzalisha. Taasisi ya Utafiti wa Hali ya Hewa ya Finland (FMI) imeshiriki katika ujenzi wa ICA tangu katikati ya miaka ya 1990 chini ya uongozi wa meneja wa utafiti Dk Walter Schmidt. Chombo cha angani kilichowekwa katika mzunguko wa kometi ina vifaa kumi na moja vya kipimo cha kisayansi ambavyo huchukua vipimo vya maendeleo ya kometi inapokaribia jua. Wakati wao kutenganisha chembe kuunda mkia wa kometi, na kwa mara ya kwanza itakuwa sasa inawezekana kupima ukuaji wake kutoka malezi yake kwa kupungua kwake. NASA ilishuhudia kuamka kwa kometi ya barafu na jua na kuundwa kwa mvuke kabla ya Rosetta's Philae lander kutolewa na kupeleka data mpya kuhusu mmomonyoko wa uso wa kometi. - Chembe zinazotoka kwenye mkia hutoa habari kuhusu hali ya hewa ya angani ya kometi yaani. "Kulingana na Profesa Kallio, ""Mzunguko wa kometi katika anga ambapo joto linalotokana na mwangaza wa jua na upepo wa jua pamoja huharibu uso wa kometi.""" Profesa Kallio na kikundi chake cha utafiti huchanganua vipimo kutoka kwa chombo cha angani kwa kutumia uigizaji wa kompyuta wa pande tatu. - modeling sisi kutumia kwa kiasi kikubwa kina ufahamu wetu wa data kipimo sisi kupokea. Hatuwezi kupata picha kamili ya matukio ya kometi kwa kuchukua vipimo katika maeneo tofauti-tofauti, wala kwa kutumia kifaa kimoja cha kupima. Njia pekee ni kwa kuchanganua na kuchanganya matokeo ya kipimo na kutumia yao kujenga mfano. Mbali na gesi inayotokezwa na barafu, vitu vingine pia huondoka kwenye uso wa kometi. Kikundi cha utafiti cha Profesa Kallio kinatumaini kupata chembechembe nzito za vumbi ili kuchunguza baadaye. Awamu inayofuata ya kazi ya utafiti ni kulinganisha matokeo na yale kutoka kwa vyombo vingine vya kupima. - Sisi ni kuzingatia hasa juu ya fluctuations katika nguvu ya mmomonyoko wakati wa mzunguko wa maisha ya kometi. Uharibifu huo unaonekana kuwa unaongezeka wakati kometi hiyo inapokaribia jua na inadhaniwa kuwa imefikia kiwango chake cha juu mnamo Agosti 2015. Hiyo ndiyo sababu tunatarajia mlipuko zaidi wa mvuke kadiri majira ya kiangazi yanavyokaribia. Profesa Esa Kallio, Chuo Kikuu cha Aalto tel. +358 504 855 [email protected] Profesa Hannu Koskinen, Chuo Kikuu cha Helsinki tel. "Kama ilivyoelezwa katika taarifa ya ""Meteorological Institute of Finland"" (FINM), ""Meteorological Institute of Finland"" (FINM) ni shirika la utafiti wa hali ya hewa la Finland, ambalo linaendesha utafiti wa hali ya hewa." "Kama ilivyoelezwa katika makala ya ""Science and Technology"" ya mwaka huu, ""Science and Technology"" ni sehemu ya ""Science and Technology"" ya ""Science and Technology"" ya mwaka huu, ambayo ni sehemu ya ""Science and Technology"" ya mwaka huu." Chombo cha angani cha Rosetta kina orbiter na chombo cha kutua cha Philae. Mzunguko wa Rosetta utafuatilia kometi 67P-Gerasimenko hadi mwisho wa 2015. Rosetta ina vifaa 11 vya kupima vimekuwa vikiendelea kutoa data kuhusu kometi hiyo na maendeleo yake. Taasisi ya Utafiti wa Hali ya Hewa ya Finland (FMI) ilishiriki katika ujenzi wa ICA na Chuo Kikuu cha Aalto na Chuo Kikuu cha Helsinki vinafanya kazi ya kutafsiri data za kipimo. Uchunguzi huo unatarajiwa kuongeza maarifa yetu kuhusu wakati wa mwanzo wa kuundwa kwa mfumo wetu wa jua wakati kometi zilipozaliwa. Kometi pia ni zenye kupendeza kwa sababu kometi zilizogongana na Dunia zilileta maji pamoja nazo na labda molekuli za kikaboni.